taxonID	type	description	language	source
5F4487ACFFA5FFA7FE477EFEFE007914.taxon	type_taxon	Type species Lawrenceoceras collinsi Ulrich, Foerste, Miller & Unklesbay, 1944 from boulders at Point Levis, Levis County, Quebec, Canada (presumably late Floian); by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA7FE477EFEFE007914.taxon	diagnosis	Diagnosis Smooth, slender, cyrtocones with elliptically depressed cross section. Sutures directly transverse, with very shallow, broad dorsal and ventral lobes. Siphuncle small, about 0.1 of conch diameter, on convex side of conch, almost marginal in position. Siphuncular segments cylindrical or nearly so (compiled from Ulrich et al. 1944).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA5FD8D7C8CFAF67805.taxon	description	urn: lsid: zoobank. org: act: C 148361 C- 5535 - 4 AE 5 - 8835 - 282 F 9 C 8 C 3 EC 3 Figs 5 D – E, 6 A, 7 B, 8 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA5FD8D7C8CFAF67805.taxon	diagnosis	Diagnosis Exogastrically curved conch with angle of expansion of conch width of ca 8 ° and slightly depressed conch cross section (rW = 1.12); ornamented with fine directly transverse striae and rugae. Siphuncle small, 0.1 of conch height and near conch margin.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA5FD8D7C8CFAF67805.taxon	etymology	Etymology In honour to the Svalbard Husky “ Ebony ”, from the Latin ‘ hebenus ’, ‘ ebony’.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA5FD8D7C8CFAF67805.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30335; by monotypy. Type locality and horizon Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed Po 123.3, 120.3 m above base of Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA5FFA5FD8D7C8CFAF67805.taxon	description	Description Specimen FMNH-P 30335 is a fragment of a curved phragmocone and part of a body chamber with a length of 31 mm and a conch width of 9 – 13.3 mm (angle of expansion ca 8 °). The preserved part of the body chamber is 8 mm long. The conch surface is ornamented with fine directly transverse striae, 10 – 12 striae occur per mm at a conch height of ca 11 mm. The adoral ca 10 mm of the fragment surface is additionally ornamented with irregularly spaced rugae. Striae form a very shallow hyponomic sinus on the convex side of the conch curvature. The conch cross section is slightly depressed, with a height of 11.1 mm where the width is 12.5 mm (rW = 1.12). The septa are narrowly spaced, ca 10 – 12 chambers occur per distance similar to corresponding conch. At the adapical end of the specimen the septal perforation is positioned ca 0.7 mm from the conch margin positioned on the convex side of the conch curvature and has a diameter of 0.7 mm. The connecting ring is thick and with concave segments. The septal necks are short and loxochoanitic. Comparison Lawrenceoceras ebenus sp. nov. is similar in conch cross section to L. larus sp. nov., but differs from the latter species and other species of this genus in having a distinctively ornamented conch surface.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA7FFA3FDB07D9DFE857F79.taxon	description	urn: lsid: zoobank. org: act: B 0503 E 12 - D 63 A- 4656 - BAE 7 - 8 C 22 CFB 40 D 5 E Figs 5 A – C, 6 B, 7 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA7FFA3FDB07D9DFE857F79.taxon	diagnosis	Diagnosis Exogastrically curved conch with angle of expansion of conch width of ca 3 ° and slightly depressed conch cross section (rW = 1.16); conch surface smooth with fine irregularly spaced growth lines which form shallow hyponomic sinus at convex side of conch curvature; siphuncle small, 0.1 of conch height and near conch margin.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA7FFA3FDB07D9DFE857F79.taxon	etymology	Etymology From the gull genus Larus Linnaeus, 1758, a common companion during fieldwork at Profilstranda.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA7FFA3FDB07D9DFE857F79.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30351. Paratypes Five specimens (FMNH-P 30337, P 30338, P 30339, P 30342, P 30355) from bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian. Type locality and horizon Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed Po 123.3, 120.3 m, above base of Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA7FFA3FDB07D9DFE857F79.taxon	description	Description The holotype is a fragment of a curved phragmocone with a length of 65 mm, its width expands from 13.5 to 16.5 mm over a length of ca 48 mm (angle of expansion ca 4 °). The conch surface is almost smooth, ornamented only with faint irregularly spaced growth lines, which form a very shallow sinus on the convex side of the conch curvature and a broad and shallow, but distinctive hyponomic sinus at the concave side of the conch curvature. The conch cross section is depressed (rW = 1.16 – 1.23) with the dorsum slightly flattened compared with the ventral side. Ten measurements of the relative conch width including the additional material result in a mean value of rW = 1.3 (1 st – 3 rd quantile = 1.24 – 1.33, n = 10). The septa are narrowly spaced, ca 10 chambers occur per distance similar to corresponding conch height and the sutures form a shallow lobe at the lateral flanks (rCL = 0.1). The septal curvature is relatively strong, ca 2 – 3 mm at the adapical end of the specimen. The septal perforation is positioned almost at the margin of the conch on the convex side of the conch curvature and has a diameter of 1.5 mm at a position where the conch height is 13 mm. In specimen FMNH-P 30355 details of the siphuncle and septal necks are preserved. There, the connecting ring is thickened with concave segments and the septal necks are short loxochoanitic. No endosiphuncular and / or cameral deposits are known. Comparison The new species differs from other species of Lawrenceoceras in having a relatively low angle of conch width expansion; it also differs from the type species in having a more depressed conch cross section (rW in L. collinsi is ca 1.06). Lawrenceoceras confertissimum (Whitfield, 1886) from the Fort Cassin Formation, New York, USA has a larger rate of expansion of the conch width (12.5 ° compared with 4 ° in L. larus sp. nov.). Lawrenceoceras australe (Ulrich et al., 1944) from the Odenville Limestone, Alabama, USA differs in having a more depressed conch (rW = 1.34) with a distinctive triangular conch cross section.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA0FD937E5FFB2678B5.taxon	type_taxon	Type species Gomphoceras cassinense Whitfield, 1886 from the Fort Cassin Formation (Floian) at Fort Cassin headland, Vermont, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA0FD937E5FFB2678B5.taxon	diagnosis	Diagnosis Gomphoceroid, breviconic orthocones with circular to depressed conch cross section; phragmocone expanding adorally rapidly; anterior half of mature body chamber slightly contracted. Sutures and growth lines straight and directly transverse; siphuncle small, rSD = 0.15, ventral in position but not marginal; septal necks orthochoanitic, connecting rings thick and layered (from King 1998).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA1FDF77DECFC2D7BF3.taxon	description	urn: lsid: zoobank. org: act: 538 BB 8 F 6 - F 83 E- 47 EA-A 28 F-AD 4 E 316 CDAFC Fig. 5 O – Q	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA1FDF77DECFC2D7BF3.taxon	diagnosis	Diagnosis Small Cyclostomiceras with adult conch width of ca 14 mm, slightly depressed conch cross section; ornamented with shallow, widely spaced, directly transverse annulations.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA1FDF77DECFC2D7BF3.taxon	etymology	Etymology Referring to the type locality.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA1FDF77DECFC2D7BF3.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30336, by monotypy. Type locality and horizon Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed Po 123.3, 120.3 m above base of Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA2FFA1FDF77DECFC2D7BF3.taxon	description	Description Specimen FMNH-P 30336 is a fragment of part of the phragmocone and a nearly complete body chamber. At the base of the body chamber the cross section is slightly depressed, the conch height is 11.8 mm, the width 12.3 mm (rW = 1.08). The maximum conch width is 13.7 mm and reached at ca mid-length of the body chamber. The length of the body chamber is 11 mm, and its aperture is simple transverse and slightly contracted with a width of 13.5 mm (angle of expansion of conch width 6 °). The conch surface is ornamented with widely rounded annuli which have a distance of ca 3 mm in distance (ca 0.25 of corresponding conch height). Additionally, distinct, irregularly spaced growth lines occur. The annuli and the growth lines form a shallow hyponomic sinus at the prosiphuncular side of the conch. The chamber spacing is narrow with a distance between two septa of ca 1.3 mm at an assumed conch height of ca 11 mm. The sutures form a very shallow lateral lobe. The siphuncle is preserved in the last chamber, and has a thickness of ca 1.1 mm and a distance from the conch margin of 0.8 mm and is presumably tubular. Comparison The conch shape and conch dimensions are almost identical to those of Cyclostomiceras minimum (Whitfield, 1886) from the Fort Cassin Formation, Vermont, USA (see Ulrich et al. 1943). However, the new species differs in possessing a weakly ornamented conch surface.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFA1FDDE7D30FAEF7EC3.taxon	type_taxon	Type species Orthoceras brainerdi Whitfield, 1886, from Fort Cassin Formation, Floian, at Fort Cassin headland, Vermont; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFA1FDDE7D30FAEF7EC3.taxon	diagnosis	Diagnosis Slender, gradually expanding orthocones with broadly elliptically depressed cross section; short chambers; sutures directly transverse, slightly sinuous, forming gentle dorsal and ventral lobes; siphuncle large, almost marginal, circular cross section; connecting ring thick, concave segments; septal necks curved orthochoanitic to loxochoanitic; endosiphuncular deposits form endocones with narrow endosiphotube and three endosiphoblades (after Flower 1941; Ulrich et al. 1944: 55; Teichert 1964: K 166).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFA1FDDE7D30FAEF7EC3.taxon	discussion	Remarks Numerous species have been assigned to Proterocameroceras, especially from the Early and Middle Ordovician of Russia (Balashov 1962, 1968) and South China (Xu & Lai 1987); some of them differ strongly from the type species. Proterocameroceras valhallfonnense sp. nov. (see below) is one of these forms. A revision of this genus is therefore desirable, but not within the scope of this monograph.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFBCFDDC7BDBFA947897.taxon	description	urn: lsid: zoobank. org: act: A 94148 C 2 - 2 CBC- 438 E-B 4 C 9 - 36 EAE 5161 A 76 Figs 9 H – I, 10 B – D, 11 C	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFBCFDDC7BDBFA947897.taxon	diagnosis	Diagnosis Slender orthocones with smooth shell and with weakly depressed conch cross section with a relative conch width (rW) of ca 1.1 – 1.2; chambers are relatively widely spaced, ca four – six chambers occur per distance similar to the corresponding conch height; the siphuncle is ca ⅓ of the diameter of the corresponding conch height.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFBCFDDC7BDBFA947897.taxon	etymology	Etymology From Valhallfonna Glacier, referring to the type region of this species.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFBCFDDC7BDBFA947897.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30427. Paratypes Specimens FMNH-P 30277 and P 30429 from type locality and horizon. Type locality and horizon Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFA3FFBCFDDC7BDBFA947897.taxon	description	Description The holotype is the most complete fragment of this species; it is a 21 mm long fragment of a phragmocone which grows from 10 – 12 mm in conch height with an angle of expansion of 5.5 ° (Fig. 9 H – I). It has a slightly depressed conch cross section and a well-preserved smooth conch surface. The chambers have a distance of ca 2.5 mm at a corresponding conch height of 10 mm (rCL = 0.25). The diameter of the siphuncle is 4 mm (rSD = 0.4) with slightly concave siphuncular segments. The connecting ring is poorly preserved but where visible of moderate thickness. The septal necks are loxochoanitic to orthochoanitic with a length of ca 0.28 of the corresponding chamber length. The siphuncle is filled with asymmetric endocones which are more pronounced and reach ca 30 mm toward the aperture at the ventral side and only ca 15 mm at the dorsal side (Fig. 10 C). The shell of the other two specimens is slender, orthoconic with a smooth surface and a slightly elliptically depressed cross section. In specimen FMNH-P 30277 a conch height of 13.5 mm relates to a width of ca 14.5 mm, and in the specimen FMNH-P 30429 the conch height is 17 mm, where the conch width is 20 mm (rW = 1.07, 1.18 respectively). The siphuncle is circular in cross section and positioned close to the conch margin, with a diameter of 5 mm in specimen FMNH-P 30277 and 6 mm in specimen FMNH-P 30429 (rSD = 0.37 and 0.35, respectively). The exact angle of expansion cannot be measured in either specimen because of the fragmentary preservation. In specimen FMNH-P 30277 the preserved septum is obliquely transverse, shifted toward the aperture at the antisiphuncular side of the conch. The suture forms a broad saddle at the lateral flanks, a broad shallow lobe at the dorsum and a pronounced broad u-shaped lobe at the venter. More details of septa and siphuncle are preserved in the specimen FMNH-P 30429, which has a chamber distance of 3 mm (ca six chambers occur per distance similar to the corresponding conch height) and loxochoanitic to orthochoanitic septal necks which are ca 0.7 mm long, where measurable (Figs 10 D, 11 C). The shape of the siphuncular segments and the thickness of the connecting ring cannot be determined with certainty in specimen FMNH-P 30277 because of poor preservation. Comparison The placement of this new species in Proterocameroceras is somewhat provisional, because the endosiphuncular deposits are poorly known and preserved. Characters of the endocones, such as the presence of endosiphoblades (Teichert 1964: K 166) and of an endosiphotube (Ulrich et al. 1944) are explicitly mentioned in the genus diagnosis (see above), but they are not preserved in the material described herein. Furthermore, P. valhallfonnense sp. nov. differs from the type species and from other Early Ordovician species of Proterocameroceras in having relatively widely spaced septa. In P. brainerdi, e. g., ca 10 – 12 chambers occur at a distance similar to the corresponding diameter. Two species assigned to Proterocameroceras from the Middle Ordovician of the Baltica paleocontinent, from Mishina Gora, western Russia, have a septal spacing which is comparable to that of P. valhallfonnense. Of these, P. gdovense Balashov, 1968 differs in having nearly tubular siphuncular segments and a thin connecting ring, and P. mishinagorense Balashov 1968 has a lower angle of expansion. In both species from western Russia the siphuncle is narrower, measuring only ca ⅓ of the conch diameter (Balashov 1968).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBEFFBDFDC37C4FFAEA78E7.taxon	diagnosis	Diagnosis Slender, orthocones with essentially simple, straight, transverse sutures and thin marginal, or nearly so siphuncle; sutures may form ventral lobe; septal necks achoanitic through loxochoanitic to nearly orthochoanitic; siphuncular segments concave, with thick connecting rings; endosiphuncular and cameral deposits unknown; diaphragms may be present in some forms (from Kröger & Evans 2011).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBEFFBDFDC37C4FFAEA78E7.taxon	discussion	Remarks The Rioceratidae were erected to include Rioceras Flower, 1964, Felinoceras Kröger & Evans, 2011, Microbaltoceras Flower, 1964, and Pachendoceras Ulrich & Foerste, 1936. Rioceras and Felinoceras, but not Pachendoceras (which is better interpreted as an ellesmerocerid of different affinity, see discussion in Evans & King 2012, and below), are longitudinally faintly curved with the siphuncle at the concave side of the curvature, and are hence slightly endogastrically curved. The direction of the curvature of the conch is – as well as their loxochoanitic septal necks – the rationale behind classifying the newly erected, slightly endogastrically curved, partly annulated longiconic genera of the Olendisletta Member within the Rioceratidae and not within the closely similar Rudolfoceratidae Ulrich, Foerste, Miller & Unklesbay, 1944 (see also below). Kröger & Landing (2009) revived the Rudolfoceratidae for a group of annulated, breviconic to longiconic ellesmerocerids with slightly exogastrically curved conchs, with thin connecting rings with concave segments (see also Evans 2011). The group with high probability comprises a paraphyletic set of genera which can be phylogenetically positioned basal to the Orthocerida and Dissidocerida Zhuravleva, 1964 (see below). The paraphyletic grouping is also evident by the presence of a spherical protoconch in Ethanoceras gen. nov. and a cup-shaped apex in Svalbardoceras gen. nov. (see below). Further studies and new finds with early ontogenies preserved are needed in order to better resolve the phylogenetic relationships of the genera which are now placed within the Rioceratidae.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFBDFDBD7DBFFCB97CBF.taxon	description	urn: lsid: zoobank. org: act: 7 D 492453 - 6 BC 0 - 4 F 56 - 8 DD 4 - 806 D 508 E 9 DD 4	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFBDFDBD7DBFFCB97CBF.taxon	type_taxon	Type species Ethanoceras solitudines gen. et sp. nov. from the Olenidsletta Member, V 2 trilobite zone, Blackhillsian, Floian; by monotypy.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFBDFDBD7DBFFCB97CBF.taxon	diagnosis	Diagnosis Longiconic orthocones with angle of expansion of ca 5 °, with circular conch cross section; shell surface ornamented with distinctive, narrowly spaced transverse striae; strongly eccentrically positioned siphuncle with relative siphuncle diameter rSD ≈ 0.16; septal necks relatively long, s-shaped orthochoanitic to loxochoanitic; connecting rings are thick and slightly s-shaped in sagittal section; cameral and endosiphuncular deposits not known.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFBDFDBD7DBFFCB97CBF.taxon	etymology	Etymology Referring to Ethan, the name of a Svalbard reindeer, Rangifer tarandus platyrhynchus (Vrolik, 1829), browsing at the Profilbekken area during the summer of 2017.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFBDFDBD7DBFFCB97CBF.taxon	description	Comparison Ethanoceras gen. nov. differs from other Rioceratidae in having a siphuncle that is completely detached from the conch margin. Specimens of Ethanoceras gen. nov. with conch cross section diameter <6 mm can be distinguished from Bactroceras boliviensis Aubrechtová, 2015 in having only a very weak transverse ornamentation and a distinctive septal neck. Nevadaceras conicum Flower, 1968 differs in having a compressed conch cross section and a slightly expanded siphuncle with thin connecting rings. In Michelinoceras toquimense Flower, 1968 the siphuncle is strictly tubular and eccentrically positioned on the convex side of the conch curvature. The shape of the septal necks of Ethanoceras solitudines gen. et sp. nov. is unique among the Rioceratidae and related taxa; it is morphologically transitional to species with relatively long and partly curved septal necks such as Hemichoanella canningi Teichert & Glenister, 1954 and Lebetoceras oepiki Teichert & Glenister, 1954, known from late Tremadocian – early Floian beds of the Emanuel Formation, Western Australia.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	description	urn: lsid: zoobank. org: act: 6627 FF 29 - 392 E- 46 AF- 89 AC-D 4528 B 10385 A Figs 12 I, 13 A, 14 – 15, 16 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	diagnosis	Diagnosis Same as for genus, by monotypy.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	etymology	Etymology From the Latin ‘ solitudine ’, ‘ loneliness’.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30383. Paratypes Twenty-five specimens (P 20265, P 30191, P 30384 to P 30404, P 30406, P 30433, P 30435, P 30436; see Supp. file 1 for list of specimens): twenty-two from bed PO 123.3, and three from bed PO 131 Profilbekken section, adjacent to Hinlopenstretet; 120.3 and 128 m above base of Olenidsletta Member, V 2 trilobite zone, Blackhillsian, late Floian. Five additional microscopic specimens (FMNH-P 30173, P 30174, P 30192, P 30423, P 30463) from bed PO 123.3. Type locality and horizon Profilstranda section, adjacent to Hinlopenstretet, bed PO 131, 128 m above base of Olenidsletta Member, V 2 trilobite zone, Blackhillsian, late Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	description	Description The holotype is a 40 mm long orthoconic fragment of a phragmocone with a diameter of 3.4 – 6.1 mm; it has a circular conch cross section and an apical angle of ca 4 °. This is similar in the entire sample. The total sample has a circular conch cross section and a mean angle of expansion of 4 ° (1 st – 3 rd quantile: 3 ° – 5 °; n = 10) (Fig. 14). The angle of expansion continuously decreases with growth and with maximum values in those fragments with the smallest diameters (Fig. 14). The conch surface is ornamented with very fine but distinctive, narrowly and irregularly spaced striae (Fig. 13 A). In the holotype ca 10 – 12 striae occur per one millimeter; these are directly transverse. The relative chamber length (rCL) varies between 0.3 and 0.6 in the macroscopic specimens and is ca 0.55 in the holotype (Fig. 14). The microscopic fragments have relative chamber lengths of 0.6 – 0.8, indicating a decrease in rCL during ontogeny. The siphuncle is positioned between the conch center and conch margin with a rSP of 0.08 – 0.12, except in the fragments with the smallest diameter preserved, where the maximum rSP is 0.18 at a conch diameter of 2.2 mm (specimen FMNH-P 30463). The measurements indicate a slight shift of the siphuncle from more detached positions in early growth stages toward more marginal positions in later growth stages. The relative diameter of the septal perforation (rSD) varies between 0.16 and 0.21; it is ca 0.16 in the holotype (Fig. 14). The septal necks are uniquely shaped and relatively long: in specimens FMNH-P 30395 and FMNH-P 30394, where the conch diameter is ca 5 mm, the septal perforation is 0.8 mm, and the chamber length is ca 1.8 mm, the length of the septal neck is 0. 4 – 0.5 mm (0.2 – 0.3 of corresponding chamber length). The necks are s-shaped at the dorsal (toward the conch center) side of the connecting ring and have a loxochoanitic distal tip (Figs 15, 16 A). At the ventral (toward the conch margin) and lateral sides the necks are loxochoanitic. The connecting ring is relatively thick. Where the siphuncle is 0.8 mm in diameter, the thickness of the connecting ring is ca 0.13 mm and it is slightly s-shaped, with the maximum diameter of the connecting ring segment within the adapical third of the chamber. The protoconch is preserved in specimen FMNH-P 30173, a slightly curved fragment with a length of 8 mm which shows traces of a very fine transverse striation at its adoral end. The protoconch is spherical with a diameter of 0.9 mm and distinguished from the shaft by a distinctive constriction with a diameter of 0.8 mm. The maximum diameter of the fragment is ca 1.4 mm. The chamber lengths are difficult to evaluate, but apparently the first two or three chambers have a length of 0.5 – 0.6 mm, the fifth and sixth chambers are shortened, with a distance of 0.4 – 0.5 mm only, and the subsequent chambers have a length of ca 0.7 mm.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	discussion	Remarks The single apical fragment with a protoconch preserved can be assigned to Ethanoceras solitudines gen. et. sp. nov. because several fragments of this species exist which preserve intermediate growth stages from different individuals. These pieces can be assembled together, helping to reconstruct the complete early growth of this species. The early growth stages are very similar to those of Bactrites boliviensis in general shape and dimensions, and differ mainly in having a higher rate of expansion at sections just adoral to the protoconch (the shaft), where B. boliviensis is almost tubular and E. solitudines gen. et sp. nov. grows with an angle of ca 4 – 7 °.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBFFFB8FDFB7816FBB67907.taxon	description	Stratigraphic and geographic range V 2 trilobite zone, Olenidsletta Member, Blackhillsian, Floian, Early Ordovician.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBAFFB9FDB07C9EFDEF7945.taxon	description	urn: lsid: zoobank. org: act: 1 B 85 F 4 BE-F 04 C- 4 D 03 - A 909 - 29003 ACF 507 B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBAFFB9FDB07C9EFDEF7945.taxon	type_taxon	Type species Hinlopoceras tempestatis gen. et sp. nov. from Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBAFFB9FDB07C9EFDEF7945.taxon	diagnosis	Diagnosis Longicones with slightly curved endogastric curvature during early ontogeny and orthoconic growth during later ontogeny, with cross section changing from circular in juvenile to compressed in adult growth stages; angle of expansion decreases during growth from ca 14 ° to 10 °; ornamented with distinct transverse growth lines and striae; weak transverse annuli occur during latest growth stages; approximately four chambers occur at a distance similar to the corresponding conch height; siphuncle narrow with diameter ca ⅛ of corresponding conch height, strictly marginally positioned, with slightly concave segments and loxochoanitic septal necks.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBAFFB9FDB07C9EFDEF7945.taxon	etymology	Etymology Referring to Hinlopen Strait, Svalbard, the type region of this genus.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBAFFB9FDB07C9EFDEF7945.taxon	description	Comparison The new genus is unique within the Rioceratidae in having a combination of a relatively large angle of expansion, wide septal spacing, and a distinct transversely lirate ornamentation. The internal characters of this genus are relatively poorly known, because most specimens available have a strongly recrystallized phragmocone. The thin marginal siphuncle is nearly tubular or only very slightly concave, which can best be compared with that of Svalbardoceras gen. nov. The consistently poor preservation of the internal shell of specimens of Hinlopoceras gen. nov. in beds where internal features of Svalbardoceras gen. nov. are better preserved indicates that the septa were originally more fragile and sensitive to early dissolution and / or implosion. Species of Hinlopoceras gen. nov. can be distinguished from species of Svalbardoceras gen. nov. by their distinct ornamentation; in Hinlopoceras gen. nov. the conch is ornamented with transverse bands or striae, in Svalbardoceras gen. nov. the ornament consists of fine irregularly spaced growth lines.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBBFFB7FDF07C5CFCE87827.taxon	description	urn: lsid: zoobank. org: act: 8 D 1729 CE- 0726 - 42 C 1 - 85 C 9 - E 2 AE 55 BDC 1 C 6 Figs 17 D – F, I, 18, 19 B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBBFFB7FDF07C5CFCE87827.taxon	diagnosis	Diagnosis Hinlopoceras gen. nov. with cross section changing from circular in juvenile growth stage to ca 0.9 in adult specimen; angle of expansion decreases during growth from ca 14 ° to 10 °; ornamented with distinct directly transverse, irregularly spaced lirae, 1.5 – 3 lirae occur per millimeter, and with weak, directly transverse annulations in latest growth stages. Siphuncle narrow with diameter 0.15 of corresponding conch height, strictly marginally positioned.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBBFFB7FDF07C5CFCE87827.taxon	etymology	Etymology From the Latin ‘ tempestas ’, ‘ storm’; referring to its wave-like distinct transversely lirate ornamentation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBBFFB7FDF07C5CFCE87827.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30360. Paratypes Fifteen specimens (FMNH-P 30450, P 30357 to P 30359, P 30260 to P 30269, P 30479) all are from type locality and type horizon. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spistbergen, from bed PO 07, 4.0 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFBBFFB7FDF07C5CFCE87827.taxon	description	Description The conch is curved and has a cross section that changes from circular during early growth stages, with diameters less than 10 mm, to slightly compressed (rCW ca 0.9) in later growth stages (Fig. 18). The conch expands in conch height with an angle of 9 ° – 14 ° and in conch width from 9 ° to 13 °. The conch curvature also decreases adorally, with specimens> 10 mm in conch height having a nearly orthoconic conch with an angle of expansion of ca 10 ° (Fig. 18). The conch ornament consists of distinct, directly transverse lirae which are relatively widely spaced and form a shallow hyponomic sinus on the concave side of the conch curvature (Figs 17 D, 19 B). In specimen FMNH-P 30268 the distance between lirae is 0.3 mm to 1 mm where the conch height is 7 mm, and sometimes several subordinate finer lirae occur between two more pronounced lirae. Two specimens have the siphuncle preserved; in the holotype the siphuncle is marginally positioned at the concave side of the conch curvature, and 0.4 mm wide where the conch cross section is 2.9 mm. In specimen FMNH-P 30365 the siphuncle has a diameter of 1.2 mm where the conch cross section is 7.2 mm. The chamber length is known from two specimens only; in the holotype the chamber length is 0.7 mm at a corresponding conch height of 3 mm, and in FMNH-P 30269 the septa have a distance of 1 mm where the conch is 3.7 mm in diameter. The largest fragments (specimens FMNH-P 30358, FMNH-P 30362) have maximum conch heights of 16.4 mm and 17 mm, respectively, and are ornamented additionally with a weak transverse annulation, which is more pronounced adorally. The distance between the rounded annuli is ca 3 mm and ca seven lirae occur per cycle of annulation. Comparison See comparison of Hinlopoceras venti gen. et sp. nov.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB5FFB2FD9A7D7EFB607823.taxon	description	urn: lsid: zoobank. org: act: BFD 524 AB- 81 E 0 - 4 B 03 - 9467 - 42 F 127845 E 61 Figs 17 G – H, J, 18, 19 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB5FFB2FD9A7D7EFB607823.taxon	diagnosis	Diagnosis Hinlopoceras gen. nov. with cross section changing from circular in juvenile growth stage to slightly compressed (rW ≈ 0.8) in adult specimen; angle of expansion decreases during growth from ca 14 ° to 11 °; ornamented with distinct irregularly spaced directly transverse lirae which are more pronounced during later growth stages. Siphuncle narrow with rSD = 0.12, strictly marginally positioned and with loxochoanitic septal necks.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB5FFB2FD9A7D7EFB607823.taxon	etymology	Etymology From Latin ‘ ventus ’, ‘ wind’; referring to its wave-like faint transversely lirate ornamentation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB5FFB2FD9A7D7EFB607823.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30266. Paratypes Two additional specimens from the type locality: FMNH-P 30267 from bed PO 7.5 and FMNH-P 30262 from bed PO 07, 4.5 m and 4.0 m above the base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian. Type locality and horizon From Profilstranda section, adjacent Hinlopenstretet, Spitsbergen, from bed PO 7.5, 4.5 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB5FFB2FD9A7D7EFB607823.taxon	description	Description The conch is curved in growth stages less then ca 10 mm, and almost orthoconic in later growth stages; its conch height increases at an angle of 14 ° in early growth stages and 11 ° – 13 ° in later growth stages (Fig. 18). The degree of compression increases during growth, with specimens> 10 mm in conch height with rW ≈ 0.9 or less (Fig. 18). The ornament consists of transverse lirae which are less pronounced and faint during early growth stages; conch almost smooth in growth stages with conch height <7 mm; at conch height> ca 9 mm the lirae are well expressed, with a distance of ca 0.3 – 0.6 mm (specimens FMNH-P 30266, P 30267). In specimen FMNH-P 30262 the distance between two major lirae is 0.7 mm with one subordinate lira in between at a conch height of ca 14 mm (Fig. 19 A). The siphuncle is preserved in the adapical part of specimen FMNH-P 30266, where the conch diameter is 3.4 mm and the siphuncular diameter is 0.4 mm. Comparison Hinlopoceras venti gen. et sp. nov. differs from H. tempestatis gen. et sp. nov. mainly in its less pronounced ornamentation, which is faint during early growth stages and consists of irregularly spaced transverse lirae of different strength in growth stages with conch height larger than ca 8 – 9 mm. Hinlopoceras tempestatis gen. et sp. nov. has pronounced lirae throughout its entire growth (except the very adapical ca 10 mm, Fig. 17 I) and a clear differentiation between primary and secondary lirae exists throughout its growth. Little is known about the internal characters of H. venti gen. et sp. nov. because all specimens of the sample have a strongly recrystallized phragmocone. The general similarity of this species with H. tempestatis gen. et sp. nov., however, suggests a similar chamber spacing, siphuncular position and shape.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB0FFB3FD8D7D7BFBE47B22.taxon	description	urn: lsid: zoobank. org: act: AE 232 B 80 - 8 CB 8 - 45 F 8 - A 9 BA- 80620 CD 0 D 41 C	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB0FFB3FD8D7D7BFBE47B22.taxon	type_taxon	Type species Svalbardoceras sterna gen. et sp. nov.; Early Ordovician, late Floian, Olenidsletta Member, Valhallfonna Formation Öland, Spitsbergen.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB0FFB3FD8D7D7BFBE47B22.taxon	diagnosis	Diagnosis Weakly curved endogastric longicones with angle of expansion 5 ° to 7 °; shell ornamented with shallow, irregularly spaced undulations, which are more pronounced in later growth stages, and with fine but distinct irregularly spaced directly transverse, imbricate growth lines; three to four chambers occur per distance similar to the corresponding conch cross section; thin marginal siphuncle with rSD ≈ ⅛ to ¹ / 6, siphuncle marginally, or nearly so, positioned at concave side of conch curvature; septal necks loxochoanitic to orthochoanitic; connecting ring relatively thick with slightly concave segments, almost tubular, endosiphuncular and cameral deposits not known.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB0FFB3FD8D7D7BFBE47B22.taxon	etymology	Etymology Referring to Svalbard, the type region of this genus.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB0FFB3FD8D7D7BFBE47B22.taxon	description	Comparison This new genus is unique within the Rioceratidae in having a combination of relatively wide septal spacing, a thin marginal siphuncle and an ornamentation with shallow, irregularly spaced undulations that are more pronounced in later growth stages. The similarly annulated and weakly curved Felinoceras Kröger & Evans, 2011 differs in having a narrower septal spacing and a distinctive annulation throughout its growth. Semiannuloceras Evans, 2005 differs in possessing, in addition, a longitudinal ornamentation. The conch of Rioceras Flower, 1964 is smooth throughout its entire growth.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB1FFB1FDEE7E79FC857B22.taxon	description	urn: lsid: zoobank. org: act: F 4069 C 31 - 5 F 45 - 44 C 0 - A 05 D- 03223749 C 9 DE Figs 12 B, 16 C – D, 19 D, 20 – 21, 22 E – G, 23 A, C, E, G	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB1FFB1FDEE7E79FC857B22.taxon	diagnosis	Diagnosis Slightly curved longicones with compressed conch cross section; with shallow irregularly spaced undulations that are more pronounced in later growth stages and with fine, irregularly spaced, directly transverse imbricate growth lines which form a shallow hyponomic sinus at prosiphuncular side of the conch; thin marginal siphuncle with rSD ≈ 0.13, siphuncle positioned at concave side of conch curvature; septal necks orthochoantic to loxochoantic, connecting ring nearly tubular, weakly concave.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB1FFB1FDEE7E79FC857B22.taxon	etymology	Etymology Referring to the laridid genus Sterna Linneaus, 1758, birds which were common companions during our field work at Profilstranda, Ny Friesland.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB1FFB1FDEE7E79FC857B22.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30368. Paratypes Forty-four specimens (P 30368 to P 30382, P 30437 to P 30449, P 30451 hasta P 30462, P 30465, P 30466, P 30468 to P 30470; see Suppl. file 1 for list of specimens) from type locality, two from bed PO 07, fortytwo from bed PO 7.5, 4 m and 4.5 m above the base base of the Olenidsletta Member, Valhallfonna Formation, V 1 a trilobite zone, Blackhillsian, Floian. Two additional specimens (FMNH-P 30169, FMNH-P 30172) from bed PO 7.5 are apical fragments. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed PO 7.5, 4.5 m above the base of the Olenidsletta Member, Valhallfonna Formation, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB1FFB1FDEE7E79FC857B22.taxon	description	Description The conchs are slightly curved with an angle of expansion of conch width <ca 9 ° (mean angle of expansion = 6.7 °, 1 st – 3 rd quantile: 5.7 – 7.8; n = 12), and of conch height <12 ° (mean angle of expansion = 7 °, 1 st – 3 rd quantile: 6.6 – 9.3; n = 14). The conchs reach their largest angle of expansion in growth stages with conch heights of 10 – 17 mm (Fig. 20). The conch cross section is compressed with a mean rW = 0.89 (1 st – 3 rd quantile: 0.86 – 0.92; n = 29) (Fig. 21). The conch surface is ornamented with growth lines or growth bands and weak irregularly spaced annulations, which are more pronounced in specimens with conch height> 10 mm. Annulation and ornamentation are slightly obliquely transverse, shifted toward aperture at antisiphuncular side and form a shallow hyponomic sinus at the prosiphuncular side. In some specimens, e. g., FMNH-P 30379, the conch surface appears to be finely imbricated (Fig. 22 E). The siphuncle is marginal, positioned at the concave side of the conch curvature with a mean rSD = 0.13 (1 st – 3 rd quantile: 0.11 – 0.15; n = 4). The sutures are directly transverse with an rCL between 0.27 and 0.36 (Fig. 21). The septal necks are loxochoanitic to orthochoanitic. The connecting ring is relatively thin and forms slightly concave segments, which can vary within one specimen from nearly tubular to slightly s-shaped (Fig. 23 E – G). The largest known specimen is a fragment of a phragmocone, FMNH-P 30446, with a maximum diameter of 22 mm. Two specimens preserve the apical parts of the conch. In the apical 0.5 mm FMNH-P 30169 reaches 1.7 mm in diameter; increasing to 2.2 mm at a distance 2 mm from the apex, and then respectively 3 mm at 5 mm and 6 mm at 17 mm. The conch has a slightly compressed cross section. The extreme ca 0.5 mm of the apex of specimen FMNH-P 30169 was broken during preparation, is poorly preserved and the presence or absence of a cicatrix is not possible to determine. Comparison Svalbardoceras sterna gen. et sp. nov. differs from S. skua gen. et sp. nov. in having a compressed conch cross section. Svalbardoceras sterna gen. et sp. nov. is similar to Bactroceras morguesi Kröger & Evans, 2011 with respect to the angle of expansion and the slight conch curvature, but the latter differs in having a circular conch cross section and in not being annulated.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB3FF8EFD977E79FC937E6D.taxon	description	urn: lsid: zoobank. org: act: 9385 D 872 - 8656 - 4 B 53 - 9 CA 8 - 05 F 7575 BEB 6 F Figs 16 B, 19 C, 20 – 21, 22 A – D, 23 B, D, F	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB3FF8EFD977E79FC937E6D.taxon	diagnosis	Diagnosis Slightly curved longicones with circular conch cross section; shell ornamented with shallow, irregularly spaced undulations that are more pronounced in later growth stages and with fine, irregularly spaced, directly transverse growth lines or bands; thin, nearly marginal siphuncle with relative siphuncle diameter of ca 0.16 of corresponding conch cross section, siphuncle positioned at concave side of conch curvature; septal necks orthochoanitic; connecting ring relatively thick with slightly concave segments, weak hyposeptal and episeptal deposits occur.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB3FF8EFD977E79FC937E6D.taxon	etymology	Etymology Referring to Stercorarius skua (Brünnich, 1764), a bird which was a common companion during our field work at Profilstranda, Ny Friesland.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB3FF8EFD977E79FC937E6D.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30272. Paratypes Nine specimens from type locality, one from bed PO 123 (FMNH-P 30271), eight from bed PO 123.3 (FMNH-P 30263, P 30264, P 30273, P 30275 to P 30277, P 30408, P 30471), 120 – 120.3 m above the base of the Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed PO 123.3, 120.3 m above the base of the Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFB3FF8EFD977E79FC937E6D.taxon	description	Description The conchs are slightly curved with angle of expansion of <ca 7 ° (mean angle of expansion = 4.8 °, 1 st – 3 rd quantile: 3.3 – 4.8; n = 7), which decreases with conch size from ca 11 ° to 5 ° (Figs 20, 22 A – D). The conch cross section is invariantly circular. The conch surface is ornamented with fine growth lines or growth bands (Fig. 29 C) and annulations, which are slightly obliquely transverse, and shifted toward the aperture at the antisiphuncular side. The sutures are slightly obliquely transverse and shifted toward the aperture at the antisiphuncular side. The relative chamber length (rCL) decreases with increasing conch cross section (Fig. 21), ranging from ca 0.25 to more than 0.3. The siphuncle is marginally positioned, very slightly removed from the conch margin (Fig. 23 B), at the concave side of the conch curvature with a mean rSD of 0.16 (1 st – 3 rd quantile: 0.13 – 0.19; n = 4). The septal necks are orthochoanitic. The connecting ring is moderately thick and forms slightly concave siphuncular segments (Fig. 23 F). Weak epi-, and hyposeptal deposits occur in the extreme apical part of specimen FMNH-P 30274 at a conch height of ca <2.8 mm. In one specimen part of the body chamber is preserved (specimen FMNH-P 30276); the body chamber is> 26 mm long and the conch diameter at the position of the last septum is 5.5 mm. Comparison See above, under Svalbardoceras sterna gen. et sp. nov.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8CFF8FFDDA7B24FE717BDF.taxon	diagnosis	Emended diagnosis Slender orthoconic to weakly cyrtoconic shells with usually faint ornamentation consisting of transverse growth lines or low striae; siphuncle marginal, narrow; dorsomyarian muscle scars; septal necks orthochoanitic to hemichoanitic, connecting rings thin and homogeneous, slightly expanded into chambers; embryonic shell moderately large, subspherical and with constriction; cicatrix absent (slightly modified from King & Evans 2019).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8CFF8FFDDA7B24FE717BDF.taxon	discussion	Remarks The diagnosis of the Bactroceratidae King & Evans, 2019 is emended with respect to the statement of a presence or absence of endosiphuncular and cameral deposits, which follows a discussion of the type genus of this family (see below). A statement about the presence or absence of deposits is removed from the diagnosis herein.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8DFF8DFD887EF6FC137EE1.taxon	type_taxon	Type species Bactroceras avus Holm, 1898; Middle Ordovician, late Darriwilian Stage, Seby Limestone Formation; Öland, Sweden; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8DFF8DFD887EF6FC137EE1.taxon	diagnosis	Diagnosis Slender, orthocones or weakly curved cyrtocones with sub-circular or circular conch cross section; apical angle low, typically below 10 °; surface sculpture with straight, transverse growth lines or annulations, and / or striae; hyponomic sinus broad and shallow; phragmocone chambers rather deep, concavity at least 0.3 of conch height; sutures straight and transverse; distance between two sutures between 0.25 and 0.5 of corresponding conch cross section; siphuncle marginal or slightly removed from shell margin; diameter of the siphuncle between ¹ / 7 and ¹ / 20 of corresponding conch cross section; septal necks orthochoanitic to hemichoanitic; siphuncular segments tubular to slightly expanded; connecting rings thin and homogeneous (adopted from Aubrechtová 2015).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8DFF8DFD887EF6FC137EE1.taxon	discussion	Remarks One of the diagnostic characters of Bactroceras, given in Aubrechtová (2015), is the absence of endosiphuncular deposits. This is a slight emendation of previous diagnoses of the genus by Aubrechtová (2015) adopted by King & Evans (2019). In Kröger & Evans (2011) the diagnosis reads “ endosiphuncular deposits unknown ” and in the original diagnosis of Bactroceras of Holm (1898) no statement about endosiphuncular deposits is given. With the discovery of endosiphuncular deposits, herein, in a species which is very similar to the type species of Bactroceras, the subtle emendation by Aubrechtová (2015) becomes crucial. Accepting it would require the erection of a new genus, which would be identical to Bactroceras, but which would differ in the known presence of endosiphuncular deposits. Alternatively, the original genus diagnosis could be revived again, so that potentially species with endosiphuncular deposits can be included. Here the latter solution of the problem is suggested, because it is very difficult, and often impossible, to definitively make a statement on the absence of endosiphuncular deposits. A sufficiently large sample of apical fragments to contain individuals that grew large enough to have developed endosiphuncular deposits is required. This character (the absence of deposits) would render the genus very difficult to practically apply to species, or it would increase the risk that it becomes a wastebasket taxon for inadequately known fragments (e. g., Ormoceras Stokes, 1840). And more generally, the absence of a feature, such as endosiphuncular deposits, whose presence theoretically cannot be ruled out, is a diagnostic character that can be falsified, even if the chances of falsification are low. Therefore, the original diagnosis of Holm (1898) is here taken as a reference. Thoraloceras Kröger & Evans, 2011, which is a troedsonellid with a marginal siphuncle with endosiphocones, similar to Bactroceras, and which occurs in Tremadocian strata of the Montagne Noir, differs from the latter mainly in having a wider siphuncle (¼ of the conch cross section) and a smooth conch surface.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8FFF87FDCD7BB9FCF378C8.taxon	description	Figs 12 E, H, J, 13 C, 24 – 27, 28 A – B, 29 B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8FFF87FDCD7BB9FCF378C8.taxon	diagnosis	Diagnosis Bactroceras with a large shell diameter (> 45 mm), ornamented with transverse striae, and with concavity of septa of 30 %; siphuncle tubular, marginal; diameter of siphuncle ⅛ to ¹ / 7 of the corresponding conch diameter; connecting ring very thin (after Aubrechtová 2015).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8FFF87FDCD7BB9FCF378C8.taxon	materials_examined	Material examined Sixty-eight specimens (see Supp. file 1 for list of specimens); one from bed PO 7, two from bed PO 7.5, two from bed PO 123.3, and 62 from bed PO 131, 4 m, 4.5 m, 120.3 m, and 128 m above base of Olenidsletta Member, V 1 – V 2 trilobite zone, Blackhillsian, Floian. An additional number of 15 microscopic specimens from bed PO 131.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8FFF87FDCD7BB9FCF378C8.taxon	description	Description The conchs are straight and expand gradually with a low angle of expansion, ca 4 ° (mean 3.7 °; 1 st – 3 rd quantile: 2.7 – 4.5; n = 37) (Fig. 24). The conch cross section is invariantly circular. The largest specimen in the sample is a fragmentary body chamber with a maximum diameter of ca 48 mm and a length of 92 mm (specimen FMNH-P 30179). At the base of the body chamber, where the diameter is 38 mm, a narrow paired dorsomyarian muscle scar is preserved (Fig. 25 A). The conch surface is ornamented with striae, which are directly transverse and run parallel to the sutures (Figs 13 C, 25 B – D). The striae are very slightly shifted toward the apex at the prosiphuncular side, forming a very shallow ventral sinus. The striae have partly an imbricated profile in well preserved specimens and are rounded in less well preserved and smaller specimens. The spacing of the striae increases with growth in relation to the conch diameter (Fig. 24), reaching densities between 1 – 20 lirae per one millimeter. The relative chamber length varies between 0.6 in the smallest preserved growth stages with diameters of less than 5 mm and 0.2 in the largest specimens with diameters> 35 mm. The diameter of the septal foramen is ca ¹ / 6 of corresponding conch cross section (mean rSD = 0.17; 1 st – 3 rd quantile: 0.15 – 0.19; n = 55) (Fig. 26). The rSD decreases with conch diameter toward 0.15 at a maximum conch diameter of 43 mm (Fig. 26). The siphuncle is eccentric, positioned between the center of the conch and the conch margin in early growth stages with conch cross section diameters <6 mm, and it is nearly marginal in later growth stages (Fig. 26). The septal necks are orthochoanitic and the siphuncular segments are tubular and have a thin connecting ring (Fig. 27). The siphuncles of specimen FMNH-P 30215 from bed PO 131, and specimens FMNH-P 30243 and FMNH-P 30259 from bed PO 7.5 (Figs 27 A – D, 28 A – B), contain an irregular conical continuous endosiphuncular lining, which adapically fills the entire siphuncle but thins out adorally within a length of ca 20 – 30 mm at conch diameters of up to 38 mm. The conch apex consists of a nearly spherical protoconch with a mean diameter of 1.1 mm (1 st – 3 rd quantile: 1.1 – 1.2; n = 15) and a mean length of 1 mm (1 st – 3 rd quantile: 1.0 – 1.1; n = 15), which is distinguished from a shaft by a shallow, often very indistinct constriction (Figs 12 J, 29 B). The spherical initial part is smooth, without a cicatrix (Fig. 12 H), and the following ca 5 – 10 mm of the initial part of the conch is nearly smooth. In some well-preserved specimens a faint, narrow, transverse ornamentation is visible, which becomes more pronounced during growth. The shaft and the following ca 5 – 10 mm are almost straight and have a very low angle of expansion or are tubular. At a distance of 25 mm from the apical tip the conch is only 2.7 mm wide in specimen FMNH-P 30165. The caecum is elongated; in specimen FMNH-P 30176 it is ca 0.4 mm long and 0.3 mm wide, directly marginal and reaches only through the adoral half of the initial chamber, which is 0.7 mm long. Septal crowing occurs in specimen FMNH-P 30176 between the second to fourth septum with a distance between 0.4 and 0.5 mm, and the subsequent four chambers have a length of 0.7 – 0.9 mm (Fig. 29 B).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF8FFF87FDCD7BB9FCF378C8.taxon	discussion	Remarks The assignment of the specimens described above to B. boliviensis is justified herein by the combination of the distinctively pronounced transverse ornamentation, a relatively wide siphuncle, and a relatively large adult size. The relative siphuncular diameter of the Olenidsletta Member specimens is on average slightly wider than that of the holotype and syntype of B. boliviensis. However, the range of measurements of the two types is well within the range of our specimens (see Fig. 24). Another species of Bactroceras with a similarly wide siphuncle (rSD = ¹ / 6) is B. wilsoni Flower, 1968 from the Antelope Valley Limestone, Nevada, USA, which differs, however, in lacking the distinctively striated ornamentation. The types of B. angustisiphonatum (Rüdiger, 1889) differ from the Bactroceras specimens of the Olenidsletta Member in having a very narrow siphuncle with an rSD of ca ¹ / 12 (Holm 1898: 9) to ¹ / 11 (Rüdiger 1889: 37). Additionally, the ornamentation of B. angustisiphonatum, as originally described by Rüdiger (1889: 37), is weak; Rüdiger (1889) referred to it as “ Anwachsstreifen ”, i. e., growth lines (this is in contrast to his use of the term “ Ringlinien ”, i. e., transverse striae, e. g., Rüdiger 1889: 38). The relatively weak ornamentation, with growth lines only, of the original material of B. angustisiphonatum is also explicitly mentioned in Holm (1898: 9). Bactroceras sandbergeri (Barrande, 1867) differs also in having a siphuncle with a diameter of <0.1 of the corresponding conch cross section (Aubrechtová 2015). Evans (2005) described an assemblage of ca 40 specimens from the Olenidssletta Member, collected by R. A. Fortey and D. L. Bruton, under “ B. angustisiphonatum (Rüdiger, 1891) ” (sic!). The assemblage came from “ the top of division V 2 ” (Evans 2005: 28), with high probability from exactly the same horizon as most of the specimens assigned to B. boliviensis herein. Bactroceras boliviensis is distinctive within the orthocones of the Olenidssletta Member and occurs in great numbers at 128 m above the base of the member at Profilstranda. The specimens from the Olenidssletta Member described by Evans (2005) are therefore with high probability in large part conspecific with the specimens described herein under B. boliviensis. Our measurements add to the knowledge of the variability of this assemblage, and specifically the dimensions and characters of the apical parts are almost identical (compare Evans 2005: text-fig. 8 e). However, B. boliviensis co-occurs with Ethanoceras solitudines gen. et sp. nov., which differs in having a less pronounced ornamentation and a non-marginal, eccentrically positioned siphuncle throughout its entire growth. This makes the distinction between Bactroceras and Ethanoceras difficult or impossible in specimens with diameters <6 mm and without well preserved outer shell or extreme apical parts. Therefore, we measured only specimens with a well-preserved shell surface. Our results differ slightly from the measurements of Evans (2005: text-fig. 8) in having a strictly marginal siphuncle position in B. boliviensis in specimens with diameters> ca 6 – 7 mm. This difference is potentially a result of unrecognized specimens of Ethanoceras solitudines gen. et sp. nov. in the sample of Evans (2005). Stratigraphic and geographic range The types and previously only known specimens of B. boliviensis are from the Pircancha Formation, Bolivia, Baltograptus minutus graptolite zone, which is time equivalent to the lower part of the Didymograptus bifidus graptolite zone (see Gutiérrez-Marco & Martin 2016). The D. bifidus graptolite zone reaches into the upper part of the V 1 division of the Olenidsletta Member (Cooper & Fortey 1982). The specimens described herein are from V 1 – V 2 trilobite zones; hence the species is known from the Blackhillsian, late Floian of Bolivia and Spitsbergen.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	description	urn: lsid: zoobank. org: act: A 0 C 49 BC 7 - 0551 - 4 BD 0 - ABC 5 - 77 A 446 BBF 5 D 1 Figs 12 D, 29 A, C – D, 30	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	diagnosis	Diagnosis Bactroceras with smooth shell or very faint transverse ornamentation; angle of expansion relatively low, ca 5 °; siphuncle slightly expanded within chambers, marginal; diameter of siphuncle ca ¹ / 5 of the corresponding conch diameter during early growth stages, increasing during ontogeny.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	etymology	Etymology From the Latin ‘ fluvius ’, ‘ river’, referring to the type locality of this species.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30177. Paratypes One additional specimen from type locality and horizon and 18 specimens from Profilbekken river basin, locality PR-phosphatic, adjacent to Hinlopenstretet, Spitsbergen, uppermost Olenidsletta Member, V 3 trilobite zone, Dapingian. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, topmost exposed layer ca 153 meters above the base of the Olenidsletta Member, V 3 trilobite zone, Dapingian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	description	Description The holotype is an apical part of a phragmocone with a length of 32 mm, with a maximum measurable diameter of 3.3 mm, and a subspherical protoconch with a diameter 1.1 mm (Fig. 29 C – D). The conch surface is apparently smooth and the conch cross section circular. The protonconch is clearly distinguished from the subsequent shaft by a constriction with a diameter of 0.9 mm at a distance of ca 1 mm from the apical end of the shell. The conch is weakly curved with a concave curvature at the ventral (prosiphuncular) side and grows within the first 2 mm only to a conch diameter of 1.1 mm. A diameter of 1.3 mm is reached at a distance 5 mm from the apical end of the shell. The siphuncle is marginal throughout the entire length of the holotype, it is tubular to slightly expanded within the chambers and has a diameter of 0.6 mm at the adoral end of the specimen (rSD = 0.18). The septal necks are short orthochoanitic with a length of ca ⅓ of the length of the siphuncular segment. The chamber spacing varies greatly depending on the growth stage. The first chamber has a length of 0.6 mm, the next three chambers, which are roughly at the position of the constriction and initial shaft, are very short, with lengths of 0.25 – 0.35 mm, and the subsequent chambers have a length of 0.5 – 0.7 mm. At a conch diameter of 3.3 mm the chamber length is 1.2 mm (rCL = 0.37) and the septum curvature is 0.7 mm deep. The caecum is slightly elongated and reaches through the adoral half of the initial chamber with a length of 0.35 mm and a maximum diameter of 0.3 mm. The septal perforation of the first septum has a diameter of 0.2 mm. In specimens FMNH-P 30168 and FMNH-P 30177 (holotype) the sutures of the initial growth stages are well preserved. They run directly transverse and form a shallow ventral lobe in the vicinity of the ventral siphuncle (Fig. 12 D). Only two specimens with diameters >> 3 mm are available. Specimen FMNH-P 30200 is a natural sagittal section through a phragmocone with a diameter of 2.2 – 7.5 mm and a length of 34 mm (angle of expansion 9 °), a siphuncular diameter of 1.5 mm (rSD = 0.21) and a chamber height of 3.8 mm (rCL = 0.51) at the adoral end of the fragment. The largest specimen (FMNH-P 30167) is a straight, ca 97 mm long fragment of a phragmocone with partly imploded septa with circular conch cross section, a smooth conch surface and a diameter of 12 – 19 mm (angle of expansion 4.4 °) (Fig. 29 A). The specimen has a marginal siphuncle with a 4.5 mm wide siphuncle at a corresponding conch cross section of 14.5 mm (rSD = 0.31) and a septal distance of 7.5 mm at the same position on the conch (rCL = 0.51). The septal necks are 1.7 mm long where the siphuncular segment is 7.5 mm long, and the septa have a curvature of 5 mm where the diameter of the septa is 14 mm.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	discussion	Remarks The sample of specimens of Bactroceras fluvii sp. nov. consists of 18 microscopic specimens with diameters <3 mm or slightly larger, one specimen with a maximum diameter of 7.5 mm and a single specimen with conch diameters of 12 – 19 mm. The large specimen differs from the microscopic specimens in its large relative siphuncle size (rSD = 0.31) and in its deep septal curvature (Fig. 30). Because no transitional growth stages are known, the combination of the two size classes and the assumption of large ontogenetic changes is somewhat speculative. However, because a similar increasing rSD is known from Bactroceras mourgesi Kröger & Evans, 2011, which also has a slightly expanded siphuncle, the assumption of a similar change in the phragmocone dimensions in B. fluvii gen. et sp. nov. is not unrealistic.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF85FF85FDA87DC0FACA7841.taxon	description	Comparison This new species of Bactroceras is similar to B. mourgesi, from the Tremadocian of the Montagne Noire, in having a slightly expanded siphuncle with a diameter of ca 0.2 of the conch diameter and in having slightly curved early growth stages. Bactroceras fluvii gen. et sp. nov. differs from B. mourgesi in its concave curvature on the prosiphuncluar side in early growth stages and in having a lower angle of expansion. Bactroceras boliviensis differs in its distinctively striated conch and in being nearly tubular and straight immediately adoral of the protoconch. Additionally, the siphuncle of B. boliviensis is nearly tubular. Other species of Bactroceras have a narrower siphuncle (compare Aubrechtová 2015).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF85FDDA7A1BFB427C17.taxon	type_taxon	Type species Cyptendoceras ruedemanni Ulrich & Foerste, 1936; from Fort Cassin Formation, Floian Stage, from near Fort Cassin, Vermont, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF85FDDA7A1BFB427C17.taxon	diagnosis	Diagnosis Straight, slender, depressed conchs with short camerae; sutures with ventral lobe, in some forms also dorsal lobe; siphuncle ventral with tubular or faintly concave segments; short septal necks; endosiphuncular rod; cameral deposits adjacent to siphuncle are present (adopted from Flower 1964).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF85FDDC7D99FB197E8C.taxon	diagnosis	Emended diagnosis Straight longicones with siphuncle marginal or submarginal, relatively wide with concave or convexoconcave segments; septal necks short, loxochoanitic to orthochoanitic; connecting rings relatively thick; endosiphuncular deposits form thick ventral rod which merges adapically into a complete siphuncular filling, diaphragms unknown; cameral deposits epi- and hyposeptal, concentrated on prosiphuncular side.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF85FDDC7D99FB197E8C.taxon	discussion	Remarks The diagnosis of the Cyptendoceratidae largely follows Zhuravleva (1994), but is more restricted following the emendation of the Baltoceratidae by Kröger et al. (2007), in which rod-bearing smooth longicones with tubular siphuncles, such as Rangeroceras Hook & Flower, 1977, Rhabdiferoceras Flower, 1964 and Veneficoceras Hook & Flower, 1977, are now included within the Baltoceratidae. The family now contains rod-bearing smooth and annulated forms with concave siphuncular segments and includes four genera: Cyptendoceras Ulrich & Foerste, 1936, Amsleroceras Hook & Flower, 1977, Catoraphiceras Ulrich & Foerste, 1936, and Hemichoanella Teichert & Glenister, 1954.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF82FD49798DFBF4789A.taxon	description	Fig. 9 F – G	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF82FD49798DFBF4789A.taxon	materials_examined	Material examined Specimen FMNH-P 30426, from Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed PO 07, 4 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF82FD49798DFBF4789A.taxon	description	Description The specimen is a fragment of a slightly crushed 30 mm long portion of a body chamber with the last septum preserved. The conch is smooth, straight and slender and has an elliptically depressed cross section with a height of 18 mm and a width of 22 mm (rW = 1.22). The preserved septum forms a suture that is slightly oblique across the flanks of the conch shifted toward the aperture at the antisiphuncular side of the conch; it forms shallow lateral saddles, is almost transverse dorsally, and forms a deep, broad u-shaped ventral lobe. The siphuncle is marginally positioned and elliptically depressed with a septal perforation 8 mm in height and 9 mm in width (rSD = 0.4). No details of the septal necks or the connecting ring are preserved.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF87FF82FD49798DFBF4789A.taxon	discussion	Remarks The specimen is assigned to Cyptendoceras because of the presence of the characteristic u-shaped ventral lobe. However, neither the septal spacing, nor the details of the septal necks and connecting ring are known, which precludes a species level determination of the specimen.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF80FF83FD497C31FD057B22.taxon	description	Figs 12 A, 31 C	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF80FF83FD497C31FD057B22.taxon	materials_examined	Material examined Specimens FMNH-P 30166 and FMNH-P 30472, from Profilbekken river basin, locality PR-phosphatic, adjacent to Hinlopenstretet, Spitsbergen, uppermost Olenidsletta Member, V 3 trilobite zone, Dapingian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF80FF83FD497C31FD057B22.taxon	description	Description The larger specimen, FMNH-P 30166, is a fragment of a phragmocone with smooth shell, a circular or slightly compressed conch cross section with diameters 31 – 38 mm and a length of 82 mm (angle of expansion ca 5 °). The siphuncle is marginally positioned, is subcircular or slightly depressed in cross section with a height of 11.5 mm, where the conch height is 36 mm (rSD = 0.32). The septa are imploded and crushed. Where visible they are 5 mm apart at a conch height of 34 mm (rCL = 0.15) with the sutures forming a distinct ventral lobe. The septal necks are loxochoanitic with a length of 1.2 – 1.7 mm where the siphuncular segment is 5 mm long (0.24 – 0.34 of chamber length). The connecting ring is slightly concave and poorly preserved, making an estimation of its thickness impossible (Fig. 31 C). The second specimen, FMNH-P 30472 (Fig. 12 A), is a 20 mm long apical portion of a phragmocone with a smooth outer surface and a slightly compressed conch cross section. This fragment is slightly curved with the siphuncle marginally positioned at the concave side of conch curvature. The siphuncle is empty and apparently circular in cross section, with a diameter of 1.4 mm where the conch height is 4 mm. The extreme apex is cup-shaped without constriction and grows from its extreme tip toward a conch height of 1.3 mm within the apical 1 mm; at a distance of 2 mm from the tip the conch is 1.7 mm high, at a distance of 5 mm the conch height is 2.3 mm. The angle of expansion between 1 mm from tip toward the adoral end of the specimen is ca 7 °.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF80FF83FD497C31FD057B22.taxon	discussion	Remarks These specimens are assigned to Cyptendoceras because they combine a relatively wide marginal siphuncle and (in the larger specimen) concave segments, loxochoanitic septal necks and a ventral sutural lobe, although the preserved parts of the siphuncle are empty. Most species of Cyptendoceras have a narrower chamber spacing and a slightly depressed cross section. In C. mesleri Ulrich, Foerste, Miller & Unklesbay, 1944 only five chambers occur in a distance similar to conch height, which is comparable to the rCL of specimen FMNH-P 30166. However, neither C. mesleri nor the specimens described above allow for detailed comparison and the fragmentary character of the available specimens do not allow for a species level determination.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF81FF83FDDE7E7AFC667900.taxon	type_taxon	Type species Catoraphiceras lobatum Ulrich & Foerste, 1936; probably from the Powell horizon (late Floian – early Dapingian Stage), Wells Creek basin, northeast of Erin, Tennessee, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF81FF83FDDE7E7AFC667900.taxon	diagnosis	Diagnosis Annulated orthocones whose sutures form ventral lobes; cross section is depressed to circular; siphuncles are moderately large (rSD = 0.25 – 0.35) and somewhat removed from the venter; septal necks are short; connecting rings are thin; some species develop ventral rods and cameral deposits (adopted from Hook & Flower 1977).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF81FF83FDDE7E7AFC667900.taxon	discussion	Remarks The genus was previously placed within the Protocycloceratidae.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF82FF80FE227D0AFC8F7E38.taxon	type_taxon	Type species Hemichoanella canningi Teichert & Glenister, 1954, from Emanuel Formation, stage III (Bendigonian – Chewtonian, see Legg 1978; Floian), Emanuel Creek, Kimberley Division, Western Australia; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF82FF80FE227D0AFC8F7E38.taxon	diagnosis	Diagnosis Orthoconic longicones with circular conch cross section; sutures with deep, narrow siphonal lobe; siphuncle marginal, nearly tubular with rSD ≈ 0.3; septal necks hemichoanitic, connecting ring thick (compiled from Teichert & Glenister 1954 and Furnish & Glenister 1964).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF82FF80FE227D0AFC8F7E38.taxon	discussion	Remarks The genus is provisionally placed within the Cyptendoceratidae because of the presence of a relatively wide siphuncle with relatively long septal necks and concave, relatively thick connecting rings (see additional remarks below in chapter Cladistic Analysis).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	description	urn: lsid: zoobank. org: act: F 8 F 91097 - 8 EF 4 - 454 F- 8317 - F 4 AA 1 A 270616 Figs 32 C, 33 A – B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	diagnosis	Diagnosis Hemichoanella with ca three directly transverse annulations at distance similar to conch diameter and ornamented additionally with finely transverse striae; conch cross section circular; angle of expansion ca 5 °; relatively wide marginal siphuncle with rSD of 0.36; septal necks hemichoanitic.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	etymology	Etymology From ‘ hidden’, in Latin ‘ occultus ’, because of its Catoraphiceras - like external morphology.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30420; by monotypy. Type locality and horizon From Profilstranda section, adjacent Hinlopenstretet, Ny Friesland, Spitsbergen; bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	description	Description The holotype is a ca 17 mm long fragment of a phragmocone with a slightly compressed or circular conch cross section with a conch height of 7 – 8.4 mm (angle of expansion ca 5 °). The conch is annulated with ca three directly transverse annulations at a distance similar to the corresponding conch cross section. Additionally, it is ornamented with ca 10 fine striae that run parallel to the annuli. The sutures are directly transverse at the flanks and at the antisiphuncular side and are not exposed at the prosiphuncular side. The chambers have a distance of ca 2.1 – 2.5 mm (3 – 4 chambers per corresponding conch cross section). The septal position does not correspond with the position of the annuli, some septa occur in the valleys, others in the rings of the annuli. The siphuncle is marginal and relatively large with a diameter of ca 3 mm at the adoral end of the specimen (rSD = 0.36). The connecting ring is not preserved. The septal necks are hemichoanitic, 0.6 – 1 mm long.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF83FF9FFDB37E1CFAA97BB0.taxon	discussion	Remarks The internal characters of this species are similar to those of H. canningi Teichert & Glenister, 1954, hitherto the only known species of Hemichoanella ‚ which, however, has a smooth shell. Externally H. occulta sp. nov. is similar to species of Catoraphiceras, which differ in having shorter, orthochoanitic septal necks. Notocycloceras yurabiense Teichert & Glenister, 1954 differs in having subholochoanitic septal necks. Anthoceras warburtoni Teichert & Glenister, 1954, A. arrowsmithense Stait & Laurie, 1985, and Notocycloceras yurabiense Teichert & Glenister, 1954 differ in having subholochoanitic septal necks. The siphuncle of Anthoceras xerxes (Billings, 1865) is wider (rSD = 0.43). The Siberian forms A. angarense Balashov, 1960 and A. bajkitense Balashov, 1960 differ in having less well pronounced annulations and a narrower septal spacing, with ca 10 chambers per distance similar to the corresponding conch diameter, and A. sibiricum Balashov, 1962 has an extremely wide siphuncle with an rSD of ca 0.5.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9FFD9B7EEEFEB67F35.taxon	description	Figs 9 C, 31 A – B, 32 B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9FFD9B7EEEFEB67F35.taxon	materials_examined	Material examined Specimen FMNH-P 30431, from Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9FFD9B7EEEFEB67F35.taxon	description	Description The specimen is a 20 mm long, nearly tubular fragment of a phragmocone with a circular conch cross section, 20 mm in diameter. Eight chambers occur in the length of the fragment and the sutures are straight and directly transverse. The conch surface is poorly preserved but was apparently smooth. The chambers are internally imploded and crushed, preserving only a small part of the siphuncle. This is 7 mm in diameter and positioned between the conch center and conch margin at a distance of ca 4 mm from the conch margin. The septal necks are orthochoanitic and 0.7 mm long, where the septal distance is 3 mm. The connecting ring is relatively thin compared to the septa and septal necks and concave on the dorsal side (the side directed toward the conch center), but convex on the ventral side.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9FFD9B7EEEFEB67F35.taxon	discussion	Remarks The combination of a large, eccentric, but not marginal siphuncle with relatively narrowly spaced septa, partly concave connecting rings and short orthochoanitic septal necks are arguments to place this specimen in the Cyptendoceratidae. A combination of ventrally expanded and dorsally contracted siphuncular segments is not known from other cyptendoceratids. However, the limited information available from this species, based on a single relatively small fragment, does not allow for a better determination.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9FFDCB7A6CFBB27C9D.taxon	discussion	Remarks In the cladistic analyses (see below), Troedssonella Kobayashi, 1935 was not recovered within the same clade as other typical troedssonellids such as Buttsoceras Ulrich & Foerste, 1933, Tajaroceras Hook & Flower, 1977 and Moridunoceras Evans, 2005. Therefore, the Troedssonellidae may be polyphyletic and Troedssonella is perhaps more closely related to the Orthoceratidae instead. Since Troedssonella is the type genus of the family, this would require an emendation of the family and a new family for Buttsoceras and allied genera. However, because of the unclear relationships between many Floian dissidocerids, including the Rangeroceratidae and the Polymeridae, we refrain from establishing another family here, but point out the necessity for further studies on these relationships.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9CFDC87835FB977BBA.taxon	type_taxon	Type species Orthoceras? adamsi Butts, 1926, from the Odenville Limestone (late Floian – early Dapingian), near Odenville, St. Clair County, Alabama, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9DFF9CFDC87835FB977BBA.taxon	diagnosis	Diagnosis Slender orthocones with circular or subcircular cross section, and large subcentral siphuncles; siphuncular segments are tubular and composed of short, straight necks and thin, homogeneous connecting rings; a lamellar lining within the siphuncle thickens apically and either fills the siphuncle completely or leaves a narrow cavity dorsad of center that may be crossed by diaphragms; both hyposeptal and episeptal cameral deposits are known to develop (adopted from Hook & Flower 1977).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9EFF9DFDEB7D12FD0E791F.taxon	description	urn: lsid: zoobank. org: act: D 6 C 02 A 7 F- 2 CAF- 44 FC-A 243 - 52 AB 01 FCEB 2 C Figs 9 A – B, D – E, 11 B, 34 – 35	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9EFF9DFDEB7D12FD0E791F.taxon	diagnosis	Diagnosis Smooth orthocones with elliptically compressed conch cross sections, widely spaced chambers (relative chamber length up to ca 0.6); with large siphuncles (rSD = 0.25) which are slightly expanded into the chambers and are eccentrically positioned (rSP = 0.21); septal necks are short orthochoanitic; continuous endosiphuncular lining and episeptal deposits are present.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9EFF9DFDEB7D12FD0E791F.taxon	etymology	Etymology From Buldrebreen, a glacier near Olenidsletta, Ny Friesland, Svalbard close to the type locality of the specimen.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9EFF9DFDEB7D12FD0E791F.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30421. Paratypes Four specimens (FMNH-P 30422, P 30423, P 30428, P 30430) from type locality and horizon. Type locality and horizon Profilstranda section, adjacent Hinlopenstretet, Spitsbergen, from bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9EFF9DFDEB7D12FD0E791F.taxon	description	Description The holotype, FMNH-P 30421, is a 44 mm long, nearly straight fragment of a phragmocone with a smooth conch surface and a compressed conch with a height of 16.7 – 17.3 mm and a width of 14.8 – 16 mm (rW ≈ 0.9, angle of expansion of conch height 2 °) (Fig. 9 E). The angle of expansion is 5 ° in specimen FMNH-P 30430, which has a conch height of 21 – 23 mm. The conch surface is almost smooth with faint, irregularly spaced growth lines which may form striae with a distance between 1 and 2 mm in the holotype. The growth bands or growth lines are obliquely transverse, shifted adorally at the antisiphuncular side of the conch (visible in specimen FMNH-P 30423 and in holotype, Fig. 9 D – E). The diameter of the septal perforation of the holotype is ca 0.25 of the corresponding conch height and positioned between the center and conch margin with an rSP of 0.21. This is identical to the mean of the rSP of all five measurements from the available specimens (mean se = 0.21; minimum measured rSP = 0.21, maximum measured rSP = 0.21; n = 5). The mean relative siphuncular diameter of all measured specimens is 0.25 (range of rSD: 0.23 – 0.28; n = 6) (Fig. 34). The sutures are directly transverse. The relative chamber length varies between 0.26 and 0.58 in four measured specimens (FMNH-P 30421, P 30422, P 30423, P 30430) and decreases with conch height (Fig. 34). The septal necks are short, orthochoanitic, and in the holotype 0.6 mm long where the corresponding chamber length is ca 5 mm. The connecting ring is thin, and its segments expand slightly into the chambers (Figs 11 B, 35 A). The siphuncle is completely filled with endosiphuncular deposits in the holotype at a conch height of 14 mm and 16 mm, leaving only a questionable 0.6 mm central canal. At a conch height of 17 mm the ventral half of the siphuncle is completely filled with a massive endosiphuncular deposit. In the holotype, episeptal deposits are developed at the pro-siphuncular (ventral) side of the conch. Comparison This species is unique among species of Buttsoceras with regard to its elliptically compressed conch cross section. The type species of Buttsoceras, B. adamsi, differs in having a nearly circular to slightly depressed conch cross section and a transversally striated conch surface. The center of the siphuncle of this species is at a position with a distance of ca 0.35 of the conch height from the conch margin; this is more eccentric than in the specimens of Buttsoceras sp. of the Croisaphuill Formation (late Floian Stage), Scotland, UK (compare Evans 2011).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9FFF9AFD9E7CB6FEA17BBA.taxon	type_taxon	Type species Orthoceras lamarcki Billings, 1859, from the Fort Cassin Formation (Floian Stage), Township of Godmanchester, Huntingdon County, southwest Quebec; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9FFF9AFD9E7CB6FEA17BBA.taxon	diagnosis	Diagnosis Nearly straight, annulated longicones with circular or subcircular cross section and straight sutures; camerae narrow, about 6 – 7 over a length similar to conch cross section; siphuncle located between center and ventral conch margin; siphuncular segments concave; septal necks short, loxochoanitic to orthochoanitic; connecting ring comparatively thick; siphuncular deposits wedge out adorally at steep angle to ventral side; diaphragms in apical portions of siphuncle; epi-and hyposeptal cameral deposits more strongly developed on ventral side (adopted from Kröger & Landing 2009).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9FFF9AFD9E7CB6FEA17BBA.taxon	discussion	Remarks The genus Protocycloceras is type genus for the Protocycloceratidae Kobayashi, 1935. Based on the cladistic analysis (below) this family is abandoned. The genus clusters consistently with other members of the Troedsonellida, such as Buttsoceras (see below). The close relationship between the two genera is also suggested by the combination of diaphragms and endosiphuncular linings, which is unknown in any other genus.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF98FF99FDF67D11FCC27827.taxon	description	Figs 36 I, 37 A – B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF98FF99FDF67D11FCC27827.taxon	diagnosis	Diagnosis Slightly curved longicones with prominent undulation; conch cross section circular-subcircular; ribs directly transverse, rounded, concave interspaces; ribs and interspaces similar in size and shape; one rib and a concave interspace correspond to one chamber; sutures directly transverse; approximately 4 – 5 chambers over a length similar to conch cross section; siphuncle eccentric between center of conch and ventral conch margin; siphuncular diameter approximately one third of conch cross section; siphuncular segments concave; septal necks short, loxochoanitic to orthochoanitic; connecting ring thick; endosiphuncular rod in ventral part of siphuncle, fills entire siphuncle in more adapical part; rod wedges out adorally with steep angle toward the venter; diaphragms in adapical portions of siphuncle; epi- and hyposeptal deposits present (from Kröger & Landing 2009).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF98FF99FDF67D11FCC27827.taxon	materials_examined	Material examined Specimen FMNH-P 30409, from Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed PO 3.7, 0.7 m above base of Olenidsletta Member, and specimen FMNH-P 30418 from bed PO 04, 1 m above base of Olenidsletta Member, both V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF98FF99FDF67D11FCC27827.taxon	description	Description Specimen FMNH-P 30418 consists of a portion of a phragmocone and 3 mm of the basal part of the body chamber. In total, the length of the specimen exceeds 24 mm. The conch cross section is slightly subcircular with a diameter of 6.5 – 8.0 mm. The exact angle of expansion is unknown. The surface is ornamented with rounded, directly transverse ribs, which run parallel to the sutures and are very slightly shifted toward the apex at the prosiphuncular side, forming a very shallow ventral sinus (Fig. 36 I). Approximately one rib and one valley occur per chamber, and ca four ribs occur in a distance similar to corresponding conch cross section. The three adoral chambers counted from body chamber toward apex measure 1 mm, 1.4 mm, and 1.7 mm (rCL = 0.25 – 0.21) and probably represent adult septal chambers. The siphuncle is at least 2.2 mm in diameter (rSD = 0.28); the distance from the ventral conch margin cannot be measured with certainty but is approximately 1.4 – 1.8 mm (rSP = 0.18 – 0.25). The siphuncular segments are strongly concave and the connecting rings are thick. The septal necks of the two adoralmost chambers are preserved and are relatively long (ca 0.6 – 0.7 mm) and loxochoanitic (Fig. 37 A). An interpretation of the endosiphuncular structure is difficult because of the state of preservation of the specimen, but episeptal and mural cameral deposits are visible in the polished section of the specimen. A second specimen, FMNH-P 30409, is a naturally weathered sagittal cut of a phragmocone, exposing the siphuncle and the central parts of the septa. The conch is straight and slender. The conch cross section is only known from the ventral parts and does not allow any inference on the cross-section shape. The surface is weakly annulated with ca one undulation per chamber. The chambers have a distance of ca 1.2 – 0.7 mm. The siphuncle is 0.8 mm in diameter, with weakly concave segments and orthochoanitic septal necks, and has no endosiphuncular deposits. Episeptal cameral deposits are present in specimen FMNH-P 30409.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF98FF99FDF67D11FCC27827.taxon	discussion	Remarks The morphological characters of the two specimens, including shape and spacing of annulation, spacing of septa, siphuncular position and relative thickness and the preserved details of the connecting ring and septal necks all are within the well documented (Kröger & Landing 2009; Evans 2011) variability of P. lamarcki. This justifies the assignment of these fragments to P. lamarcki, herein. It should be noted, however, that specimen FMNH-P 30418 probably represents an adult specimen (based on adult septal crowding). With an adult size of only 8 mm it is clearly smaller than many specimens measured from the Fort Cassin Formation, New York, USA, which reach conch diameters of more than 30 mm (Kröger & Landing 2009) and from the Durness Group, Scotland, UK (Evans 2011), which reach diameters of ca 25 mm. Stratigraphic and geographic range Widespread in North America (see details in Kröger & Landing 2009), Scotland, UK (see review in Evans 2011), and Spitsbergen, herein, Floian Stage.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9BFF96FDB67D7EFD117F2E.taxon	description	urn: lsid: zoobank. org: act: C 3 D 57 CD 1 - 2758 - 40 A 3 - 8596 - 6865 D 77 F 3620 Figs 36 B – C, E – H, 37 C, 38	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9BFF96FDB67D7EFD117F2E.taxon	etymology	Etymology From the Latin ‘ minor ’, ‘ relatively small’, referring to the relatively small size of this species of Protocycloceras.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9BFF96FDB67D7EFD117F2E.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30411. Paratypes Five additional specimens (FMNH-P 30410, P 30412 to P 30415) all from type horizon and locality. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstratet, Spitsbergen, bed PO 131, 128 m above base of Olenidsletta Member, V 2 trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF9BFF96FDB67D7EFD117F2E.taxon	description	Description The holotype is a fragment of a body chamber and part of the phragmocone with a nearly circular conch cross section of 9.5 mm in diameter (Fig. 36 B, E – F). The preservation does not allow precise measurement of the angle of expansion. The preserved part of the body chamber is 12 mm long. The conch is annulated, with annulations running parallel to the sutures with a distance of ca 2 mm and a chamber length of ca 2 mm (ca 4 – 5 chambers and annulations per corresponding cross section diameter). The siphuncle is nearly tubular, has a diameter of 2.1 mm (rSD = 0.22), and is located ca 0.7 mm from the conch margin (rSP = 0.07) (Fig. 37 C). The holotype has two complete septa preserved with a distance of 2.2 mm at a corresponding conch cross section of 9.5 mm (rCL = 0.23). The septal necks are poorly preserved but appear to be orthochoanitic and with a length of ca 0.5 mm. The conch cross section is circular to subcircular and grows with an angle of expansion of ca 3 ° in the two other measured specimens (FMNH- P 30410, FMNH-P 30414). The septal perforation was measured in FMNH-P 30412 and FMNH-P 30415 with some inaccuracy because of poor preservation and varies from 0.29 to 0.34 in the two specimens. The conch surface in all specimens is ornamented with ribs and transverse striae. The ribs are directly transverse and run parallel to the sutures; they are very slightly shifted toward the apex at the prosiphuncular side, forming a very shallow ventral sinus. The ribs are more sharply rounded than the valleys, ca one rib and one concave interspace occur per chamber, and ca 3 ribs occur per distance similar to corresponding conch cross section. The relative spacing of the annulation increases with increasing conch diameter (Fig. 38). Additionally, the surface is ornamented with ca 15 – 20 fine transverse striae or growth lines per annulation. The largest specimen in the collection has a diameter of ca 12 mm (specimen FMNH-P 30415). Comparison The siphuncle is more eccentric (rSP ≈ 0.1 in P. minor sp. nov. compared with 0.25 in P. lamarcki) and thinner (ca ⅓ of the conch cross section in P. lamarcki) than in P. lamarcki. The position and dimensions of the septal perforation are similar to those of Castelloceras arennigense Evans, 2005, from the Bohaul Member of the Ogof Hên Formation, Moridunian Regional Stage (Floian), which is slightly older than division V 2 of the Olenidsletta Member. However, the details of the siphuncle are not known from that species, which precludes further comparison.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF97FDC77D99FAAB7995.taxon	type_taxon	Type species Eosomichelinoceras huananense J. - Y. Chen, 1974, from the Middle Ordovician of Southwest China; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF97FDC77D99FAAB7995.taxon	diagnosis	Diagnosis Smooth or transversally striated, slender, orthoconic baltoceratids with narrow, tubular siphuncle. Siphuncle is eccentric with rSP of more than 0.2, and with rSD ≈ 0.2 or less. Septal necks are orthochoanitic. Endosiphuncular or cameral deposits are not known (adopted from Kröger et al. 2007).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF95FDED7B0CFBC47FB7.taxon	description	urn: lsid: zoobank. org: act: C 53 AC 527 - FC 9 D- 4433 - A 853 - 5 BF 9 AE 4 C 2 B 6 C Figs 12 C, F – G, 13 B, 28 C, 33 C – E, 39 – 40	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF95FDED7B0CFBC47FB7.taxon	diagnosis	Diagnosis Eosomichelinoceras with circular to slightly compressed conch cross section; conch in early growth stages slightly curved; shell surface ornamented with narrowly spaced transverse striae which form shallow hyponomic sinus at concave side of conch curvature; siphuncle eccentric, at convex side of conch curvature with rSP of 0.36, relative siphuncle diameter (rSD) ca 0.16 of corresponding conch cross section; septal necks loxochoanitic during earliest growth stages, orthochoanitic during later ontogeny; ca three chambers per length similar to corresponding conch cross section; connecting ring thin, tubular or slightly expanded.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF95FDED7B0CFBC47FB7.taxon	etymology	Etymology From ancient Greek ‘ Βορέας’, ‘ north wind’.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF95FDED7B0CFBC47FB7.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30279. Paratypes Fourty-one specimens (FMNH-P 30171, P 30182, P 30193, P 30278, P 30280 to P 30318, P 30434; see Supp. file 1 for list of specimens) from type horizon and one specimen from bed PO 131, 128 m above base of Olenidsletta Member, all from type locality. Additionally, two microscopic fragments (FMNH-P 30170, FMNH-P 30184) from type horizon and one (FMNH-P 30182) from bed PO 131. Type locality and horizon From Profilstranda, adjacent to Hinlopenstretet, Spitsbergen, bed PO 123.3, 120.3 m above the base of the Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF95FF95FDED7B0CFBC47FB7.taxon	description	Description Conch with circular to slightly compressed cross section, exogastrically curved in juvenile growth stages, becoming nearly straight in growth stages with diameter> 10 mm. The holotype (specimen FMNH-P 30279) is a fragment of a phragmocone which growths within a length of 53 mm from 3.2 to 10 mm (angle of expansion ca 7 °). The largest conch cross section diameter known is 11.5 mm (specimen FMNH-P 30297), which is a completely preserved, nearly straight body chamber with a length of 28 mm and an angle of expansion of ca 5 °. The low angle of expansion of this fragment indicates that a diameter of ca 12 mm is probably the adult size of this species (see also Fig. 39). The ornamentation consists of fine striae, which run slightly obliquely transverse, which are deflected adorally on the convex side of the conch and form a shallow, but distinct hyponomic sinus at the concave side of the conch curvature (Fig. 13 B). The holotype is ornamented with 7 – 10 transverse striae in a length of 1 mm where the conch is 9 mm in diameter. Six random measurements from the holotype and other specimens result in a mean distance of 0.11 mm between striae. The sutures are directly transverse with a mean relative chamber length of 0.28 of the corresponding cross section. The chamber length is 2.0 – 2.5 mm at 8 – 9 mm conch diameter in the holotype. The septal perforation has a mean relative diameter of 0.16 in all measured specimens (rSD 1 st – 3 rd quantile: 0.13 – 0.16; n = 26). The siphuncle is eccentrically positioned, with rSP ≈ 0.36 on the convex side of the conch curvature (1 st – 3 rd quantile: 0.32 – 0.38; n = 5) (Fig. 40). The septal necks are short loxochoanitic in specimen FMNH-P 30193 at 7 mm diameter conch diameter and orthocoanitic in larger fragments with a larger conch diameter (Figs 28 C, 33 C – E). The connecting ring is thin with tubular or slightly expanded segments. No endosiphuncular or cameral deposits known. The extreme apical part is preserved in specimens FMNH- P 30171, FMNH-P 30182, and FMNH-P 30184 (Fig. 12 C, F – G). The initial ca 1.5 mm in both specimens are set apart from the subsequent shell in being distinctly bent in growth direction toward the convex side of the curvature of the subsequent shell, which is the prosiphuncular side. The initial ca 1.5 mm differs also in lacking the fine transverse striation of the subsequent conch parts. The protoconch has a very distinctive stump-like form with a diameter of 1 mm (specimen FMNH-P 30182) and 1.4 mm (specimen FMNH-P 30184), and a length of 0.9 mm (specimen FMNH-P 30182) and 0.7 mm (specimen FMNH-P 30184). The shaft is endogastrically curved and starts at a diameter of 1.2 mm (specimen FMNH-P 30184) and 0.9 mm (specimen FMNH-P 30182), respectively. The conch grows toward 2.8 mm within ca 17 mm in FMNH-P 30184, and reaches 2.3 mm within ca 15 mm in FMNH-P 30182. A second distinct change in growth pattern occurs at a diameter of ca 1.5 – 1.7 mm and is best seen in specimen FMNH-P 30171. There, the conch curvature abruptly decreases and the angle of expansion increases (Fig. 12 C). Stratigraphic and geographic range 120.3 m (PO 123.3) and 128 m (PO 131) above base of Olenidsletta Member, V 2 trilobite zone, Blackhillsian, Floian. Comparison Eosomichelinoceras borealis sp. nov. is unique among Eosomichelinoceras in having a slightly curved juvenile conch and a relatively wide angle of expansion of ca 7 °. The type species differs additionally in having a wider chamber spacing. In addition, in Eosomichelinoceras guizhouense Yang, 1978 the siphuncle is more central in position; in Eosomichelinoceras ordosoense Chen & Zou, 1984 additionally the siphuncle is more eccentrically positioned. Eosomichelinoceras baldisii Kröger et al., 2007 differs from the new species in having a compressed conch cross section. Apical parts of species assigned to Eosomichelinoceras are only known so far from specimens from the Olenidsletta Member, making a comparison of this growth stage with other species impossible at present.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF97FF95FE49794BFC317D82.taxon	type_taxon	Type species Cycloplectoceras miseri Ulrich, Foerste, Miller & Furnish, 1942, from the Smithville Formation (Floian Stage), north of Smithville, Lawrence County, Arkansas, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF97FF95FE49794BFC317D82.taxon	diagnosis	Diagnosis Small discoidal conch with nearly circular whorls in cross section; whorls are in contact and slightly impressed dorsally; extremely small umbilical perforation; surface ornamented with strong annulations and prominent growth lines, which form v-shaped ventral sinuses; sutures simple and nearly straight; siphuncle near the ventral wall of the conch (from Ulrich et al. 1942).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	description	urn: lsid: zoobank. org: act: 17 CC 19 A 8 - 797 C- 4718 - AE 09 - C 6 DEEF 037258 Fig. 41 C – D	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	diagnosis	Diagnosis Strongly ribbed Cycloplectoceras with rapidly enlarging conch with WER of ca 3.7 and LER of ca 2, with adult size> 30 mm.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	etymology	Etymology From Hinlopen Strait, referring to the type region of this species.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30327; by monotypy. Type locality and horizon From Profilstranda section, Ny Friesland, Svalbard, bed PO 131, 128 m above base of Olenidsletta Member, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	description	Description Specimen FMNH-P 30327 is a fragment of a phragmocone consisting of ca two whorls with a total diameter of 26 mm. The conch grows with a WER of 3.66 and a LER of 2. The whorl is 13 mm wide and high at a conch diameter of 26 mm and is slightly flattened on the lateral flanks and venter; a 0.3 mm deep imprint zone is present at the dorsum. The conch is strongly annulated with ribs than run obliquely transverse across the flanks and forming a deep and broad ventral lobe. Prominent growth lines or striae are present, ca 8 per one millimetre, and are parallel to the ribs. The siphuncular perforation has a diameter of 1.4 mm and is positioned at a distance of 1.3 mm from the venter (rSP = 0.1). The septal spacing is relatively narrow; where the conch is 22 mm in diameter the sutures have a distance of 2 mm apart over the venter.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF90FF92FDEB7E1CFB797DB7.taxon	discussion	Remarks This specimen is assigned to Cycloplectoceras because it is a ribbed tarphycerid with rapidly enlarging whorls, both in whorl height and in whorl width. The conch cross section is nearly circular, similar as in known species of Cycloplectoceras. Pionoceras Ulrich et al., 1942 is another annulated tarphycerid with high WER and rapid growth of the whorl width. Pionoceras, however, differs in having broadly subtrapezoidal whorl cross sections and a very broad venter. The fragment described above is, however, relatively small, and ontogenetic growth changes are frequent among tarphycerid species, and especially among species of Pionoceras. It is therefore possible that this specimen represents a fragment of a larger individual, which if fully preserved would exhibit an adult morphology with an aspect of Pionoceras. More material is required to fully document the ontogeny, and consequently to further support the generic assignment of this species. Cycloplectoceras hinlopense sp. nov. differs from C. miseri Ulrich, Foerste, Miller & Furnish, 1942 in being larger (the adult size of C. miseri is only 20 mm). The other known species of Cycloplectoceras, C. funatum Ulrich, Foerste, Miller & Furnish, 1942, has a smaller rate of increase in relative conch width (LER = ca 1.2, compare Ulrich et al. 1942: pl. 6 fig. 7) and is less strongly annulated.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF91FF90FDB17E1DFD7F78EA.taxon	type_taxon	Type species Deltoceras planum Hyatt, 1894, from strata of the St. George Group (Lower Ordovician) at Port au Choix, north side, western Newfoundland, Canada; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF91FF90FDB17E1DFD7F78EA.taxon	diagnosis	Emended diagnosis Rapidly expanding evolute conch possessing whorls with a compressed cross section with very shallow or lacking zone of impression; adoral portion of conch divergent from preceding whorl at maturity; no conspicuous shell sculpture; sutures form weak lateral lobes; siphuncle subventral in position (adopted from Evans 2011).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF91FF90FDB17E1DFD7F78EA.taxon	discussion	Remarks The exact location of the only known specimen of the type species is given in Hyatt (1894: 450) as “ Port au Choix, north side ” without specifying wether this relates to the Port au Choix peninsula or the town of Port au Choix. Deltoceras is listed under doubtful taxa in Teichert (1964), but Evans (2011) revived the genus and provided a concise diagnosis adopted from Ulrich et al. (1942), which is used herein. The genus diagnosis is slightly emended and expanded, herein, from being exclusively without dorsal impression zone to also having a very shallow impressive zone, in order to include Deltoceras beluga sp. nov. We justify this emendation also based on the poor knowledge on the details of the single specimen of the type species, which may also during earlier growth stages have a slightly involute conch curvature. The emphasis of this genus now is the combination of strongly compressed smooth whorls with a subventrally positioned siphuncle.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF92FFEEFDAA7DA1FCE87B93.taxon	description	urn: lsid: zoobank. org: act: 197 BA 0 EF- 574 D- 4 EEF-ADC 3 - DF 120829 D 7 C 5 Figs 41 A, 42 – 43, 44 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF92FFEEFDAA7DA1FCE87B93.taxon	diagnosis	Diagnosis Discoidal, slightly involute conch with moderately expanding whorls with relative whorl width (rW) of ca 0.7 – 08 and with slightly flattened venter. Ornamented with fine growth lines, which form broad lateral lobe and deep hyponomic sinus.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF92FFEEFDAA7DA1FCE87B93.taxon	etymology	Etymology From the Beluga whale Delphinapterus leucas (Pallas, 1776) a common guest offshore of Profilstranda in the Hinlopen Strait, Svalbard.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF92FFEEFDAA7DA1FCE87B93.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30321. Paratypes Two additional specimens, FMNH-P 30322 and FMNH-P 30326, from type locality and horizon. Type locality and horizon From Profilstranda section, Ny Friesland, Svalbard, from bed PO 07, 4 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFF92FFEEFDAA7DA1FCE87B93.taxon	description	Description The holotype is a complete specimen of ca 2.5 volutions, with a conch diameter of 42 mm and an apertural conch width and height of 12 mm and 15 mm, respectively (WWI = 0.8) (Fig. 42). The relative whorl width (rW) varies between 0.7 and 0.8 in the holotype. The conch grows with a WER of 2.78 – 1.96 between the first and last whorl and thus decreases with increasing diameter (Fig. 43). The whorls are rounded at the flanks with greatest width at ca the first third of the conch height from dorsum, ventral side slightly flattened and dorsum with shallow zone of impression (Fig. 44 A). Zone of impression ca 1 mm deep at aperture. The conch surface is ornamented with irregularly spaced fine growth lines which form a broad lobe across the flanks and a deep, rounded, V-shaped hyponomic sinus. Hyponomic sinus at aperture of holotype ca 10 mm deep. The completely preserved body chamber has a length of 250 ° at the dorsum and 220 ° at the distal end of the hyponomic sinus. The septa form a broad lateral sinus and have a ventral distance of ca 4 mm at a conch diameter of 28 mm. The umbilical window is ca 3 mm in diameter in the holotype. Comparison Besides the type species only one other species of Deltoceras was known. This second species, D. vangeni Ruedemann, 1906 from the Chazy Group, Valcour Island, New York, USA, has a nearly circular cross section and probably is an estonioceratid. The new species differs from the type species of Deltoceras in having a conch cross section with a slightly flattened venter and a shallow impression zone at the dorsum. Because the early volutions of the type species are not known and the three specimens known from the Olenidletta Member are relatively small compared with the type specimen, the possibility exists that the Olenidsletta Member specimens are conspecific with D. planum and represent earlier growth stages. The assignment of Deltoceras to the Estonioceratidae (see Evans 2011) or alternatively into the Tarphyceratidae (herein) is questionable and depends on a better knowledge of the type species. Here we place the genus provisionally in the Tarphyceratidae because of an assumed shallow dorsal impression during earlier growth stages in D. planum.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFECFFEFFDD97D0AFABF7B22.taxon	description	Gen. et sp. indet. A Fig. 45 E – F	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFECFFEFFDD97D0AFABF7B22.taxon	materials_examined	Material examined Specimen FMNH-P 30342, from Profilstranda section, Ny Friesland, Svalbard, bed PO 7.5, 4.5 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFECFFEFFDD97D0AFABF7B22.taxon	description	Description The specimen is a slightly curved, ca 19 mm long part of a body chamber, with a circular conch cross section with a diameter of 10.5 mm at the position of the last septum and 11 mm at the adoral end. The body chamber is simple conical, without constriction, and with a very shallow hyponomic? sinus at the concave side of the curvature. The conch surface is nearly smooth, ornamented only with very fine directly transverse growth lines. The shell is relatively thick, 1 mm at the base of the body chamber. The suture is directly transverse, and the septum has a concavity of ca 1.5 mm. The septal perforation is ca 1 mm in diameter and positioned ca 0.5 mm from the convex margin of the conch.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFECFFEFFDD97D0AFABF7B22.taxon	discussion	Remarks The body chamber is strongly curved but lacks an impression zone, and with the exception of the last septum the phragmocone is not preserved, which shows that the curvature is exogastric and the siphuncle is positioned close to the conch margin. The available characters indicate that the fragment is part of an estonioceratid, but a more specific determination is impossible with the material at hand.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEDFFECFDB97EBBFB887920.taxon	type_taxon	Type species Nautilus versutus Billings, 1865 (part), from Gargamelle Cove, Pointe Riche Peninsula, western Newfoundland, Canada (lower Table Head Formation, Darriwilian, see Stouge 1984); by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEDFFECFDB97EBBFB887920.taxon	diagnosis	Diagnosis Thickly subdiscoidal to subglobular conchs with rapidly enlarging, depressed whorls; mature body chamber may become evolute; ornamented with growth lines, which slope apicad from the umbilical shoulder to the hyponomic sinus, growth lines may become fasciculate, and costae may develop which are not, however, prominent, and are not ordinarily evident on the internal mold; straight transverse sutures or faint ventral saddles may develop; siphuncle initially ventral, dorsal by the completion of the second volution (adopted from Flower 1968: 44).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEDFFECFDB97EBBFB887920.taxon	discussion	Remarks The type specimens (originally described as Nautilus versutus, referred to L. whiteavesi Hyatt, 1894 by Hyatt 1894: 475) have been listed as collected from the St. George and / or Table Head Group of western Newfoundland in Ulrich et al. (1942: 78). However, Flower (1979: 223) stated “ after extensive collecting of coiled cephalopods, both from the St. George Group and in the Table Head limestone, it is clear that there is no true Litoceras in the St. George Group nor in any known late Canadian faunas. Specimens very close to L. versutum have been obtained in the Table Head limestone, from which I have obtained at least 35 large coiled cephalopods; all but one belong to Litoceras ”.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	description	urn: lsid: zoobank. org: act: 847 E 0904 - 7 D 05 - 46 EF- 81 F 3 - EDA 8 A 5 F 740 A 7 Figs 44 B, 46 – 47	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	diagnosis	Diagnosis Litoceras with relatively slender, rapidly enlarging conch, with WER of 2.3; with reniform, depressed conch cross section and WWI of ca 1.3; ornamented with fine growth lines which run obliquely across the flanks and form broad hyponomic sinus; the siphuncle is relatively wide, ca 0.25 of apertural height, and at a distance of 0.25 of the corresponding apertural height from the dorsum.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	etymology	Etymology Referring to the Profilbekken River near the type locality.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30329; by monotypy. Type locality and horizon From Profilstranda section, Ny Friesland, Svalbard, PO 131, 128 m above base of Olenidsletta Member, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	description	Description This specimen is a tectonically distorted fragment of a phragmocone and parts of a ca 180 ° long body chamber with a conch diameter of 86 mm (Fig. 46). The base of the body chamber is at a conch diameter of 58 mm, where the conch has ca three volutions, a whorl height of 21 mm, an apertural height of 20 mm and a conch width of 28 mm. The WER of the conch at the base of the body chamber is 2.3 (see Fig. 47 for comparison). In cross section the whorls are reniform and show a very broad, almost flattened venter and rounded flanks. The conch surface is ornamented with pronounced growth lines and is otherwise smooth or with very low ribs. The septal perforation at the base of the body chamber is subcentrally positioned at a distance of ca 5 mm from the dorsal margin and has a diameter of ca 5 mm. The sutures are simple and directly transverse.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEEFFEDFD907C7FFD0479C7.taxon	discussion	Remarks This specimen falls within the range of variability of Trocholitoceras walcotti with respect to the IZR, WWI, and general conch cross section shape (see Fig 47); however, at a comparable conch size it has a much larger WER than T. walcotti and the siphuncle is wider and subcentrally positioned, as seen in Litoceras. Litoceras calciferum (Billings, 1865), L. insolens (Billings, 1865), L. versutum (Billings, 1865), and L. huygenae Flower, 1968 have broader whorls. In L. whiteavsi Hyatt, 1894 the rounded flanks are more convex. Litoceras avus Barrande, 1870 (see Flower 1979) and L. adamsi Flower, 1968 have a similar WER (2.3), but the whorl cross section and exact position of the siphuncle is not known from the former, and the whorl cross section is wider in the latter. Litoceras was previously restricted to the Middle Ordovician. Notably, several specimens of Litoceras with comparatively high whorls, which are still wider than those of L. profilbekkenense sp. nov., occur in basal Whiterockian strata in Nevada, USA (Flower 1968). These strata are only slightly younger than division V 2 of the Olenidsletta Member (Fortey 1980; Fortey & Droser 1999; Loch & Ethington 2017), where L. profilbekkenense sp. nov. occurs. Therefore, L. profilbekkenense sp. nov. may be seen as a morphological and stratigraphical link between the predominantly Floian Trocholitoceras and the predominantly Middle Ordovician Litoceras.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEAFD9F7E1DFDA178D7.taxon	type_taxon	Type species Trocholitoceras walcotti Hyatt, 1894, from the Fort Cassin Limestone (late Floian Stage), Fort Cassin, Addison County, Vermont, USA; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEAFD9F7E1DFDA178D7.taxon	diagnosis	Diagnosis Moderately large, subdiscoidal, involute conchs with a ca 180 ° long body chamber; umbilical perforation very small; ornamented with prominent, partly fasciculate growth lines and low ribs which form a deep rounded ventral sinus; sutures directly transverse and nearly straight except on dorsal side where they form a shallow lobe; siphuncle small, subcentral during early adolescence, dorsal or nearly so at maturity (from Ulrich et al. 1942: 80).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEBFDE97DCEFA8E7EAA.taxon	description	Figs 41 B, 44 D, 47	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEBFDE97DCEFA8E7EAA.taxon	diagnosis	Diagnosis Trocholitoceras with moderately expanding whorls with WER decreasing during growth from ca 2 to 1.7; whorl cross section moderately involute with average IZR 0.26, and depressed with WWI decreasing with conch size from more than 2 to less than 1.5; conch surface ornamented with prominent transverse growth lines and low rounded ribs at mature body chamber which curve apicad on the lateral side and form a deep, rounded hyponomic sinus; siphuncle subcentral in earliest growth, subdorsal during later growth; mature conch with diameter ca 90 mm with 4 – 5 volutions (compiled from Ulrich et al. 1942: 80 – 81).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEBFDE97DCEFA8E7EAA.taxon	materials_examined	Material examined Three specimens (FMNH-P 30325, FMNH-P 30328, FMNH-P 30333) from Profilstranda section, Ny Friesland, Svalbard, bed PO 131, 128 m above base of Olenidsletta Member, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEBFDE97DCEFA8E7EAA.taxon	description	Description The most complete specimen is FMNH-P 30328 with a presumed conch diameter of more than 80 mm and the last volution slightly evolute (Fig. 41 B). At a conch diameter of 42 mm the whorl is 20 mm wide, 19 mm high, with an apertural height of 12 mm, and an impression zone with a depth of 6 – 7 mm. The depression of the whorl decreases with increasing diameter, with WWI nearly 2.5 at an apertural height of 6 mm to 1.5 at an apertural height of 20 mm. The WER is 1.96 at a conch diameter of 42 mm (Fig. 47). The IZR varies between ca 0.1 and 0.4 (Fig. 47). The whorl cross section has broadly rounded flanks and venter (Fig. 44 D). The conch surface is ornamented with prominent transverse growth lines. The siphuncle is 2 mm distant from the dorsal margin in specimen FMNH-P 30325, where the apertural height is 6.5 mm, while its and diameter is ca 1 mm. In specimen FMNH-P 30328 the siphuncle is nearly marginal at whorl heights greater than 8 mm and has a diameter ca ¹ / 10 of the apertural height.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE8FFEBFDE97DCEFA8E7EAA.taxon	discussion	Remarks Measurements taken from the median cross section of the types of T. walcotti and T. latum (Ulrich et al. 1942: text-fig. 22) reveal a large overlap in WER, IZR, and in the relative whorl width (WWI, Fig. 47) between both species. This is especially relevant in the case of the WWI, because T. latum was originally distinguished from T. walcotti based on the broader and lower whorls of the former (Ulrich et al. 1942: 83). The wide overlap suggests synonymy between the two species, with T. walcotti having priority. The two specimens from the Olenidsletta Member are slightly less involute, have less depressed whorls at growth stages less than 20 mm, but fall within the variability of the WER of T. walcotti and are also similar in whorl cross section shape, ornamentation and position of the siphuncle. Altogether this similarity justifies the assignment of these specimens to T. walcotti. Trocholithoceras walcotti (and T. latum) were previously known from the Fort Cassin Limestone, Vermont and the St. Armand Limestone, Quebec.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE9FFE9FEB97BE1FDEA795D.taxon	description	Figs 44 C, 48	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE9FFE9FEB97BE1FDEA795D.taxon	diagnosis	Diagnosis Trocholitoceras with relatively narrow whorls and prominent ribs throughout entire growth; sutures directly transverse with dorsal lobe; siphuncle located close to the dorsal wall in mature portions of the phragmocone (compiled from Ulrich et al. 1942: 82).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE9FFE9FEB97BE1FDEA795D.taxon	materials_examined	Material examined Six specimens (FMNH-P 30323, P 30324, P 30330, P 30332, P 30344, P 30347), all from Profilstranda section, Ny Friesland, Svalbard, bed PO 131, 128 m above base of Olenidsletta Member, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE9FFE9FEB97BE1FDEA795D.taxon	description	Description Specimen FMNH-P 30323 (Fig. 48 A – B) is the most complete specimen assigned this species; it is a fragment of a phragmocone, which is partly heavily recrystallized and part of a 140 ° long continuously growing body chamber, and which grows with a WER of 2.03. At the base of the body chamber the conch diameter is 37 mm and the whorl is 16.5 mm wide and 11 mm high (rW = 1.05). The slightly depressed cross section has flattened flanks, a rounded venter and a shallow imprint zone (0.6 mm at whorl height 11 mm) (Fig. 44 C). The conch is ornamented with prominent ribs which run obliquely transverse across the whorl and form a deep hyponomic sinus over the venter; ca 20 ribs occur per volution and the distance of the ribs is ca 4 mm at the base of the body chamber. Additionally, the conch surface is finely striated with ca 5 striae per mm, which run parallel to the ribs. The annulation appears to be constant in amplitude and relative spacing over the entire preserved part of the specimen. On the imprint of the inner shell a wrinkle layer is visible (Fig. 48 A). The septal perforation is ca 2.9 mm in diameter and positioned sub-dorsally, ca 1.5 mm from the dorsum at the base of the body chamber. The chamber distance is visible in specimen FMNH-P 30324, which is a small fragment of a phragmocone with a conch diameter of 22 mm, where at a conch width of 12 mm the septal distance is ca 2 mm at the venter. The sutures are straight and directly transverse. In specimen FMNH-P 30332 the whorl width is 15 mm where the whorl height is 13 mm (rW = 1.15).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE9FFE9FEB97BE1FDEA795D.taxon	discussion	Remarks In the type material of T. juvenicostatum, from the St Armand limestone (Middle Ordovician, see Salad Hersi et al. 2007 for age constraint of St. Armand limestone), Quebec, Canada, described by Ulrich et al. (1942), the rW decreases from 1.2 at a whorl height of 6.5 mm to 0.91 at a whorl height of 12 mm, and the conch grows with a WER of 2.5. This is slightly different from our material. However, the type material of T. juvenicostatum is slightly tectonically distorted and the measurements therefore reflect some preservation effects. Also, little is known about intraspecific variation of this species. The assignment of the specimens from the Olendisletta Member to T. juvenicostatum is justified by the presence of prominent ribs, the general similarity of the conch growth rate, shape of the whorl cross section and the subdorsal position of the siphuncle. The other species of Trocholitoceras with prominent ribs, T. phillipsburgense Ulrich, Foerste, Miller & Furnish, 1942, differs in having a nearly smooth surface in early volutions. Trocholitoceras juvenicostatum was previously known from the St. Armand limestone (Middle Ordovician) of Quebec.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE9FD9C7CD2FCCD7F0B.taxon	description	urn: lsid: zoobank. org: act: 46 CA 8144 - 915 D- 4392 - 90 B 9 - 7 F 123 D 2 BE 411	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE9FD9C7CD2FCCD7F0B.taxon	type_taxon	Type species Nyfrieslandoceras bassleroceroides gen. et sp. nov.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE9FD9C7CD2FCCD7F0B.taxon	diagnosis	Diagnosis Slightly curved slender conch with compressed conch cross section; ornamented with distinct irregularly spaced growth lines, which form hyponomic sinus at convex side of conch curvature; chambers are narrowly spaced, ca nine per distance similar to corresponding conch height; sutures form broad lateral lobe; siphuncle thin and nearly marginal at convex side of conch curvature, with slightly expanded segments; septal necks short, thickened achoanitic.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE7FE3F7A82FD747BE9.taxon	description	urn: lsid: zoobank. org: act: 9 E 26 DE 1 D- 597 E- 4248 - BC 5 C- 6 CB 9461 B 66 D 2 Figs 8 D, 45 A – B, 49 B – C	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE7FE3F7A82FD747BE9.taxon	diagnosis	Diagnosis As for genus, by monotypy.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE7FE3F7A82FD747BE9.taxon	etymology	Etymology Referring to Bassleroceras Ulrich & Foerste, 1936 because of its superficial similarity with this genus.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE7FE3F7A82FD747BE9.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30353. Paratype Specimen FMNH-P 30356 from type horizon and locality. Type locality and horizon From Profilstranda section, Ny Friesland, Spitsbergen, bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFEBFFE7FE3F7A82FD747BE9.taxon	description	Description The type specimen is a 62 mm long fragment of a phragmocone and a complete body chamber (Fig. 45 A – B). The conch is slightly curved with a marginal siphuncle on the convex side of the conch curvature. The preserved portion of the phragmocone has a height of 13 – 18 mm and a width of 11 – 13 mm (9 ° angle of expansion of conch height). The body chamber is simple tubular, 30 mm long and has a height of 18 – 20 mm and a width of 13 – 14 mm (4 ° angle of expansion of conch height). The body chamber is moderately compressed (with ratio conch width / conch height ca 0.7), but the more adapical parts of the fragment are less compressed (rW ≈ 0.85). The conch surface is ornamented with prominent irregularly spaced growth lines which form a distinct hyponomic sinus on the convex, prosiphuncular side of the conch curvature. The siphuncle is thin (rSD = ¹ / 16), nearly marginal, and slightly expanded within the chambers. The septal necks are thickened and very short orthochoanitic or achoanitic (Figs 8 D, 49 B – C). The sutures are obliquely transverse, form wide lateral lobes and bent forward on the convex side of the shell. Approximately nine chambers occur per length similar to the corresponding conch height at the base of the body chamber. The chamber length is 2 mm at a conch height of 18 mm. Cameral and / or endosiphuncular deposits not known. Comparison This species is externally similar to a slender Bassleroceras Ulrich & Foerste, 1936, but differs in having an expanded siphuncle with peculiar, very short or achoanitic, thickened septal necks, known otherwise only from Richardsonceras Foerste, 1933 and Richardsonoceroides Chen, 1987. The former genus is strongly curved and has a contracted adult body chamber. The latter genus is less compressed, smaller and more curved. Nyfrieslandoceras bassleroceroides gen. et sp. nov. can be conveniently classified within the Phthanoncoceratidae because of its combination of characteristic septal necks, nearly tubular siphuncle and exogastric conch curvature.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE7FD997EA0FDF87995.taxon	description	urn: lsid: zoobank. org: act: D 66 D 41 DD- 0 A 41 - 4110 - BFF 7 - 1 E 014 ED 180 FA	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE7FD997EA0FDF87995.taxon	type_taxon	Type species Olenidslettoceras farmi gen. et sp. nov., from 120.3 m (PO 123.3) above base of Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE7FD997EA0FDF87995.taxon	diagnosis	Diagnosis Slender, depressed, exogastric cyrtocones. Angle of expansion larger in apical portions. Adoral portions of mature specimens less curved and with low angle of expansion. Chambers narrowly spaced. Thin siphuncle positioned near conch margin at convex side with thick connecting rings which are tubular at the dorsal side and concave at the ventral side. Septal necks are very short, thickened, and orthochoanitic to suborthochoanitic.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE7FD997EA0FDF87995.taxon	description	Comparison See discussion of type species.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	description	urn: lsid: zoobank. org: act: 8 AE 46041 - CAE 1 - 4 ABB- 8082 - A 21 AD 56 CB 9 E 5 Figs 5 F – G, 6 D, 8 C, 50 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	diagnosis	Diagnosis As for genus, by monotypy.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	etymology	Etymology Referring to M / S Farm, the transport vessel of Henningsen Transport & Guiding A / S that brought the specimen back from Profilstranda to Longyearbyen; Spitsbergen.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	materials_examined	Type material Holotype Specimen FMNH-P 30380. Paratype One additional specimen, FMNH-P 30345, from type horizon and locality. Type locality and horizon From Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed PO 123.3, 120.3 m above base of Olenidsletta Member, V 2 a trilobite zone, Blackhillsian, Floian	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	description	Description The holotype is a 47 mm long fragment of a phragmocone with part of the body chamber preserved (Fig. 5 F – G). The conch is exogastrically curved, more so in the apical parts of the specimen. The preserved part of the body chamber is ca 15 mm long. The conch cross section is elliptically depressed, it grows in width from 9.5 mm to 14 mm and in height from 7.6 mm to 10.8 mm at a length of 36 mm (expansion of width 7 °, of height 5 °, rW ≈ 1.3). The surface of the holotype is relatively poorly preserved but is presumed originally smooth, with weak growth lines. The second specimen has a well-preserved conch surface and shows weak growth lines which run directly transverse and form a shallow and wide sinus at the antisiphuncular side of the conch. The second specimen is a fragment of a phragmocone, which grows in width from 8.7 to 11 mm and in height from 7.2 mm to 9.2 mm (expansion of width 11 °, and height 9 °) at a length of 13 mm. The corresponding rW is 1.21 and 1.19, respectively. The chamber spacing is narrow, seven to ten chambers occur at a distance similar to the conch height. The siphuncle is close to the conch margin, has thick connecting rings which are tubular at the dorsal side (the side directed toward the conch center) and concave at the ventral side (Fig. 6 D). The septal necks are short, thickened and orthochoanitic to suborthochoanitic (Figs 8 C, 50 A).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE5FFE5FDE77B0CFBAF7BB7.taxon	discussion	Remarks The curvature of the conch of this species is relatively weak compared with the other cyrtocones from the Olenidsletta Member (e. g., Lawrenceoceras larus sp. nov., Valhalloceras floweri). The species can be distinguished from the superficially similar Valhalloceras floweri by its weaker curvature and relatively low angle of expansion. The septal necks are very similar to the necks of Middle Ordovician species of Richardsonoceroides and Richardsonoceras (see Kröger et al. 2009 b: fig. 9.10 – 11). The new genus differs from Richardsonoceroides in having a depressed conch cross section and siphuncular segments with a concave ventral and tubular dorsal shape. Olenidslettoceras farmi gen. et sp. nov. is provisionally placed within the Phtanoncoceratidae because of its combination of characteristic septal necks, the presence of a partly tubular siphuncle and exogastric conch curvature.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE5FDF47EEFFDBE7C2C.taxon	type_taxon	Type species Valhalloceras floweri Evans & King, 1990 from the Olenidsletta Member, Blackhillsian, Floian; by original designation.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE5FDF47EEFFDBE7C2C.taxon	diagnosis	Diagnosis Small exogastrically curved conch with subtriangular conch cross section, venter obtusely rounded; lateral sides more acutely curved, and dorsum broadly rounded; siphuncle narrow, subventral with orthochoanitic septal necks; connecting rings thickened and differentiated; siphonal diaphragms present; sutures form weak dorsal and ventral lobes with lateral saddles; shell surface smooth with weak sinus over venter (from Evans & King 1990).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE5FDF47EEFFDBE7C2C.taxon	discussion	Remarks Evans & King (1990) placed this genus within the Phthanoncoceratidae. However, the type species of this family, Phthanoncoceras oelandense Evans & King, 1990, has strongly concave siphuncular segments, thickened connecting rings and relatively long, loxochoanitic septal necks, which is in contrast to the orthochoanitic necks and nearly tubular connecting rings known from Valhalloceras. Therefore, Valhalloceras would by definition be better placed within the Graciloceratidae (see Sweet 1964 for the diagnosis of the Graciloceratidae). However, this placing is ambiguous too, because the figured features of the connecting ring and septal necks of the type specimen of Valhalloceras are from relatively small apical parts of the phragmocone, with details of the connecting ring and septa of later growth stages either not, or poorly, preserved (see Evans & King 1990: pl. 1 figs 8, 10 – 11). The few specimens of Valhalloceras present in our collection suggest that in parts of the phragmocone from later ontogenetic growth stages the connecting rings are thick and concave (see below). If this is the case (David Evans, pers. com., agrees with this opinion) and the connecting rings in Valhalloceras are concave during later growth stages, the species is intermediate among Oncoceratida, such as graciloceratids with tubular rings and bassleroceratids with concave rings. Hence, Valhalloceras compares closely to Proterocameroceras valhallfonnense sp. nov. with its ambiguous connecting ring shape, a species that is morphologicallly transitional between bassleroceratids, such as Lawrenceoceras, and oncocerids, such as Richardsonoceras Foerste, 1933.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE2FDC8797AFBCC7CBA.taxon	description	Figs 5 H – N, 6 C, 8 B, 50 B	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE2FDC8797AFBCC7CBA.taxon	diagnosis	Diagnosis As for genus, by monotypy.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE2FDC8797AFBCC7CBA.taxon	materials_examined	Material examined Specimen FMNH-P 30343 from Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, bed PO 123.3, 120.3 m above base of Olenidsletta Member, V 2 a trilobite zone, and specimens FMNH-P 30340, P 30346, P 30348, and P 30350 from bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE2FDC8797AFBCC7CBA.taxon	description	Description Specimen FMNH-P 30343 is the externally most complete specimen (Fig. 5 H – I). It is a slightly crushed curved conch with a length of more than 30 mm which grows from 7.3 mm in height and 9.5 mm in width to 10 mm in height and 14 mm in width at a length of 15 mm (width expands with 17 °, height with 10 °). The cross section is depressed (rW: 1.3 – 1.5) and nearly elliptical at the adapical end of the specimen. The surface is ornamented with irregularly spaced fine growth lines, which run almost transversally at the ventral side and form a shallow broad sinus at the dorsal side. The internal characters of specimen FMNH-P 30343 are not preserved. Three specimens with similar relative conch shape (rW: 1.3 – 1.6) occur in bed PO 131 and are better preserved internally. In specimen FMNH-P 30340 from bed PO 131 at the Profilstranda section, the septal necks are orthochoanitic and the connecting rings are thickened and concave (figs 6 C, 50 B). The septal perforation is 1.7 mm in diameter and the connecting ring at approximately midlength between two chambers is 1.4 mm in diameter (0.11 – 0.14 of corresponding conch height). Approximately six chambers occur at a distance similar to the corresponding conch height.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE7FFE2FDC8797AFBCC7CBA.taxon	discussion	Remarks The type specimen of this species comes from a coastal outcrop between Lundehuken and Papegoyneset, adjacent to Hinlopenstretet, from a level near the top of V 2 in the terminology of Fortey (1980) (see Evans & King 1990). This is only a few kilometers south of the Profilstranda section, and at a level almost identical to beds PO 131, where the majority of our specimens of V. floweri were collected (see Fig. 1). Evans & King (1990) described and discussed Valhalloceras floweri in detail based on a single specimen, which expands laterally with an angle of 12 ° and dorsally with an angle of 19 °, and which has a relative conch width (rW) of 1.4. Both values are closely similar to the specimens described herein. The specimens are also almost identical in conch cross section shape, conch curvature, in relative septal spacing and in the shape of the septal necks. However, the only available median section from specimens from our collection shows a siphuncle with contracted segments. This difference can be an effect of different preservation. In the type specimen, the septa and partly the connecting rings are strongly recrystallized and partly only traces of the former outlines are preserved (Evans & King 1990: pl. 1 figs 8, 10 – 11). Alternatively, the difference can be true and reflect different growth stages and ontogenetic change, because the figured siphuncle in the type is from a corresponding conch height of ca 7 mm, compared with the specimen figured herein (Fig. 50 B) with a corresponding conch height of ca 14 mm. Depending on the interpretation of the differences, the genus Valhalloceras has tubular to concave or exclusively concave segments, respectively. In the former interpretation the genus would be transitional between Oncocerida and Ellesmerocerida and in the latter it would be a bassleroceratid, similar to Lawrenceoceras, but with orthochoanitic, instead of loxochoanitic septal necks. More material is needed to definitively solve this problem. Here we place the genus provisionally within the Phthanoncoceratidae, because the presence of tubular connecting rings during early growth stages is assumed to be real.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE0FFE3FD527811FC8F7903.taxon	description	Fig. 45 C – D	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE0FFE3FD527811FC8F7903.taxon	materials_examined	Material examined Specimen FMNH-P 30354, from Profilstranda section, Ny Friesland, Spitsbergen, bed PO 131, 128 m above base of Olenidsletta Member, V 2 b trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE0FFE3FD527811FC8F7903.taxon	description	Description Specimen FMNH-P 30354 is a 30 mm long fragment of a phragmocone and part of a body chamber. The preserved part of the body chamber is 14 mm long and has a compressed conch cross section with rW = 0.9 at a height of 10 mm. The angle of expansion is not known with precision, but the conch is longiconic and its width grows less than 1 mm at the preserved length of 30 mm. The shell surface is smooth. The conch is nearly orthoconic or slightly curved with the siphuncle presumably near or at the conch margin. The direction of conch curvature is difficult to determine, because the specimen is slightly distorted taphonomically, but presumably the siphuncle is at the concave side of the conch curvature. The sutures are obliquely transverse and bent forward on the convex side of the shell. Approximately five to six chambers occur per length similar to the corresponding conch height. The chamber length is 1.8 mm at a conch height of 9.5 mm (0.19 of corresponding conch width).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE0FFE3FD527811FC8F7903.taxon	discussion	Remarks This specimen is relatively well preserved externally, but the position of the siphuncle, its shape and the shape of the septal necks are unknown, which precludes any further determination. Based on the relatively narrow septal spacing and the almost straight slender conch form, the specimen is either a fragment of a bassleroceratid or a proterocameroceratid.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE1FFE3FD557C9BFB917DB6.taxon	description	Figs 11 A, 45 G, 49 A	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE1FFE3FD557C9BFB917DB6.taxon	materials_examined	Material examined Specimen FMNH-P 30424, from Profilstranda section, Ny Friesland, Spitsbergen, bed PO 4.8, 1.8 m above base of Olenidsletta Member, V 1 a trilobite zone, Blackhillsian, Floian.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE1FFE3FD557C9BFB917DB6.taxon	description	Description The specimen is a relatively well-preserved fragment representing a weakly exogastrically curved slender phragmocone with a length of 72 mm and a conch height of 17 – 23 mm (Fig. 45 G). Only the left part of the conch is preserved. Based on the preserved position of the siphuncle, the conch width can be reconstructed: the reconstructed width is ca 18 – 28 mm at either end of the preserved portion. The conch cross section, hence, is slightly compressed. The surface is ornamented with distinct, straight, transverse, rounded lirae (ca six per mm at the adapical end of the specimen) and irregularly spaced growth lines. Additionally, the conch is very weakly and irregularly undulated with a distance between two subsequent undulations between 3 and 5 mm. The ornamentation is slightly oblique, shifted toward the aperture at the antisiphuncular side of the conch. At the adoral end of the specimen the chamber distance is 7 mm. The septal perforation has a diameter of ca 7 mm at the adoral end of the specimen (rSD = 0.4) and is eccentrically positioned, with a distance of the siphuncle of ca 3 mm from the conch margin. The septal necks are long orthochoanitic to hemichoanitic and the shape of the connecting ring was presumably tubular or nearly so (Figs 11 A, 49 A).	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
5F4487ACFFE1FFE3FD557C9BFB917DB6.taxon	discussion	Remarks Given the high number of longiconic orthocones with a relatively wide subcentral, tubular siphuncle and orthochoanitic septal necks within the Baltoceratidae, Troedssonellidae, and Proterocameroceratidae in Floian and Dapingian strata, a high-level classification of this specimen is not possible until more material is available. The relatively long septal necks of this specimen are similar to those of Hemichoanella, but the siphuncle is marginal in the latter genus. More material is needed, specifically to evaluate the presence or absence of endosiphunular deposits in apical portions of the shell.	en	Kröger, Björn, Pohle, Alexander (2021): Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities. European Journal of Taxonomy 783 (1): 1-102, DOI: 10.5852/ejt.2021.783.1601, URL: http://dx.doi.org/10.5852/ejt.2021.783.1601
