taxonID	type	description	language	source
466F6C33625EFFB9968541D3FC9F35E5.taxon	type_taxon	Type species. Pseudomonticlarella varia Smirnova, 1987	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB9968541D3FC9F35E5.taxon	diagnosis	Diagnosis. Small, equibiconvex, striate, somewhat ligate; outline variable from rounded-triangular to rounded or pyriform; maximum width at midvalve; 3 to 5 lateral folds or plicae; anterior commissure with lateral folds resembling Monticlarella; ventral sulcus broadly arcuate with trapezoidal linguiform extension; ventral umbo long with pointed and slightly incurved beak; foramen small, hypothyrid. Hinge teeth long, deeply inserted; dental plates subparallel to weakly ventrally divergent; strong socket ridges; elongated hinge plates supported by strong, low septum. From Manceñido et al. 2002, p. 1314.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB9968541D3FC9F35E5.taxon	discussion	Discussion. This diagnosis is for the genus established by monotypy. Therefore, it is also the diagnosis for the type species, Pseudomonticlarella varia Smirnova. It does not require emendation in the light of the new Spitsbergen material. Occurrence. Upper Volgian – Lower (? Upper) Ryazanian.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB6968547EAFBB033E6.taxon	description	(Figs. 3.1 – 3.12, 4) 1987 Pseudomonticlarella varia new species — Smirnova, p. 33, pl. 4, figs. 1, 2, 5 – 7, text-fig. 1. 2002 Pseudomonticlarella varia Smirnova — Manceñido et al., p. 1314, fig. 891.3 a – 3 p.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB6968547EAFBB033E6.taxon	materials_examined	Material and occurrence. Seep 7 (PMO 227.419), seep 13 (PMO 227.416 – 418), seep 10 [damaged specimen, anterior commissure not present, PMO 224.923?].	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB6968547EAFBB033E6.taxon	description	Description. Small (less than 1 cm in length, width, and thickness), smooth rhynchonellide that shows traces of capillate ornament in places. However, the decortication of specimens makes it difficult to verify the ornament of the shell exterior. The anterior commissure is bisulcate with weakly developed sulcii at the commissure; central sulcus shallower than lateral sulcii. The following internal characters may be visible from external examination, either through translucent shell or because of decortication: dental lamellae in the ventral umbo; a median septum extending at least half the length of the dorsal valve. Internal characters were also determined from serial sections (Fig. 4): a small septalium-like structure is present due to the concave ventral surface of the hinge plates (Fig. 4, sections 0.3 – 0.4 mm); crura develop on the inner margins of the hinge plates (sections 0.5 – 0.7); crura arch ventrally (sections 0.7 – 1.1). Dental lamellae were not seen in the serial sections (ventral valve umbo of the sectioned specimen was damaged, Fig. 3.1 – 3.4), but observed from the external examination of specimens.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33625EFFB6968547EAFBB033E6.taxon	discussion	Discussion. The general outline and profile of the specimens from Spitsbergen are similar to those of specimens figured by Smirnova (1987, pl. 4, figs. 1 – 2) from the Russian Platform, in particular that in pl. 4, fig. 1. This specimen appears to be smooth, developing costae at the anterior margin. The Russian Platform specimens reach maximum lengths close to 6 mm (Smirnova 1987, p. 42) so are smaller than the Spitsbergen material that reach 8 mm in length. Smirnova provided serial sections of two specimens of Pseudomonticlarella varia (1987, fig. 1 a – b). Both series of sections show a septalium and crura that arch ventrally anteriorly. These are features that are shared with the Spitsbergen specimen (Fig. 4). The internal structures (from the initial section through the brachiopod) were traced for 4.12 mm in specimen No. 139 / 584 (Smirnova 1987, fig. 1 a) and for 1.45 mm in specimen No. 139 / 590 (fig. 1 b). In the Spitsbergen specimen the internal structures were traced to section 1.2 mm (i. e., 1.2 mm from the initial section through the specimen). It was thought originally that these diminutive specimens could be juveniles of the form referred herein to Ptilorhynchia mclachlani sp. nov. However, posteriorly the ventral valve of Pseudomonticlarella varia lacks any developing or incipient costae, which are often present posteriorly on specimens of Ptilorhynchia mclachlani. Also, posteriorly, the dorsal valve of Pseudomonticlarella varia is weakly sulcate (possibly enhanced by some decortication). This sulcate condition does not appear to characterize specimens of Ptilorhynchia mclachlani. In addition, Ptilorhynchia mclachlani and Pseudomonticlarella varia are not co-occuring. Obviously they should cooccur if they are conspecific (although this could reflect a collecting failure). The specimens of Pseudomonticlarella varia all occur with similar maximum dimensions and there are currently no other intermediate-sized forms between these and larger-sized species such as Ptilorhynchia mclachlani. Stratigraphic and geographic distribution. Upper Volgian – Lower (? Upper) Ryazanian of Spitsbergen and originally described from the Upper Volgian of the Russian Platform (Smirnova 1987).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB6968546DBFD0A3567.taxon	type_taxon	Type species. Ptilorhynchia plumasensis Crickmay, 1933	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	description	Figs. 3.13 – 3.32, 5 2011 v. partim ‘ Lacunosella ’ sp. — Hammer et al., p. 21, table 2, fig. 7 R. 2011 v. partim ‘ Monticlarella ’ sp. — Hammer et al., p. 21, table 2.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	materials_examined	Material and occurrence. Holotype: PMO 224.882; paratypes: PMO 227.431, PMO 227.432, PMO 224.871 – 873, PMO 224.875, PMO 224.883, PMO 217.199, PMO 224.914 (crushed). Juvenile specimens: PMO 224.876 – 879, PMO 227.433. All specimens from seep 9. Type locality. Knorringfjellet, central Spitsbergen, N 78 ° 18 ’ 49.9 ” E 16 ° 10 ’ 58.9 ”.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	etymology	Etymology. For the late Mr. Archie McLachlan, Department of Geology, Queen Mary College, University of London (see Middlemiss 1997, p. 169).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	description	Dimensions of the holotype. PMO 224.882 — Length 17.1 mm, width 18.9 mm, thickness 11.6 mm.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	diagnosis	Diagnosis. Subtriangular in outline, generally evenly biconvex in profile. Valve surface smooth except for ornament of costae which may be traceable over most of the length of the valves but are most strongly developed at the anterior commissure. Number of costae on valves variable, with typically 3 – 4 costae in the sulcus of the dorsal valve and 4 – 5 on the corresponding fold of the ventral valve. Dental lamellae present in ventral valve. Welldeveloped septalium in dorsal valve, outer hinge plates horizontal from which inner socket ridges are deflected. Crura develop at top of Y-shape of septalium, where inner and outer hinge plates meet. Anteriorly crura arch ventrally.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336251FFB396854766FBEE3486.taxon	discussion	Discussion. The beak of the ventral valve is frequently damaged / incomplete in the specimens. As a result, the dental lamellae are usually clearly visible in the umbo of the ventral valve. Juvenile specimens have costae developed over both valves, some larger specimens have costae developed primarily in the sulcus of the ventral valve and at the anterior margin. The material from Spitsbergen shows variability in outline and number of costae. The costae are traceable over most of the length of the valves. Owen (1972) described a variable species that he referred to Ptilorhynchia jeletzkyi from the latest Jurassic of British Columbia which is very similar to the material from Spitsbergen. Owen (1972, p. 2) comments on Ptilorhynchia jeletzkyi “ The shell surface is smooth, exhibiting no sign of striae, but often developing strong marginal plicae which originate midway between the umbones and anterior commissure. These plicae number from one to four ... ”. However, these strong plicae are not obvious in figured specimens (Owen 1972, pl. 1, figs. 1 – 4) or a specimen referred herein to Ptilorhynchia jeletzkyi from the Upper Jurassic (Kimmeridgian – Tithonian?) of Alaska (Fig. 6.5 – 6.8). This specimen is slightly damaged at the anterior commissure and the lateral margin, but does show the generally smooth shell ornament and the development of marginal costae (3 costae on the dorsal fold, 2 in the ventral sulcus). The number of costae in the sulcus (at the anterior commissure) in Ptilorhynchia jeletzkyi ranges from one to 4 or 5 (Owen 1972, fig. 4, pl. 1, figs. 1 c, 2 – 4). Ptilorhynchia jeletzkyi is reported from the Buchia fisheriana and B. piochii zones (i. e., Upper Tithonian, in part equivalent to the Upper Volgian). In Ptilorhynchia mclachlani, the specimens may show well-marked costae which may extend across most of the length of the specimen (e. g. Fig. 3.29). This costate shell ornament is not typical of Ptilorhynchia, which tends to show costation developed at the shell margin (e. g. species figured by Dagys 1968; Owen 1972; Owen & Manceñido 2002; and P. jeletzkyi herein, Fig. 6.5 – 6.8, and a specimen identified as P. aff. plumasensis from the Middle Jurassic of Alaska, Fig. 6.1 – 6.4 close to the type species from the Middle Jurassic Hinchman Formation (Callovian) of California (Crickmay 1933; see also Owen 1972). MacFarlan et al. (2011) claim the type horizon for P. plumasensis to be the Upper Jurassic Knoxville Formation, but their reason for this revised assignation was not given). Most of the specimens from Spitsbergen display four costae on the dorsal fold and three costae in the ventral sulcus. Due to the distinctive nature of the costation it is considered desirable to refer the Spitsbergen material to a new species rather than to the morphologically similar P. jeletzyki. The weakly costate Ptilorhynchia mclachlani resembles some species referred to Ptilorhynchia by Dagys (1968). Of these, the Spitsbergen specimens are closest to P. lenaensis in the nature of the costation of the anterior commissure but the overall size of the latter is smaller, and the number of costae on the fold and sulcus fewer than in the Spitsbergen specimens. Matching closely in outline and costation is P. anadyrensis Dagys (1968, pl. 4, figs. 3, 4) although the nature of the costation appears more angular at the anterior commissure when compared to Ptilorhynchia mclachlani. The specimens of these species figured by Dagys appear to all be decorticated. The age assignment of P. lenaensis is Valanginian (Dagys 1968) so it is slightly younger in age than the Spitsbergen specimens while P. anadyrensis was given as of uncertain age, referred questionably to the Bathonian – Callovian (Dagys 1968, table 1, p. 145). A single rhynchonellide specimen (internal cast of a ventral valve, approximately 8 mm x 8 mm) from undifferentiated Berriasian – Valanginian of the Barents Sea (Århus et al. 1990) identified as Ptilorhynchia sp., was tentatively referred to this genus. MacFarlan et al. (2011) described Ptilorhynchia pugnaciformis from the Lower Cretaceous of the Misool Archipelago, eastern Indonesia. Like other species of Ptilorhynchia already discussed, the number of costae for this species is considered to be variable (between 3 – 6 per valve; MacFarlan et al., table 1). The posterior profile of the dorsal valve in P. pugnaciformis is not as rounded as it is in P. mclachlani or P. jeletzkyi; in pugnaciformis the profile may be cynocephalous and therefore resembling, at least in profile, Homoeorhynchia Buckman. Small multicostate specimens are considered juveniles of Ptilorhynchia mclachlani. These specimens had been tentatively referred to Monticlarella by Sandy in Hammer et al. (2011); they have a similar outline to Monticlarella triloboides (Quenstedt) in Childs (1969, pl. I, figs. 5 – 7). However, the nature of the costation is consistent with Ptilorhynchia mclachlani and the broad uniplicate fold develops more strongly as the brachiopod approaches maturity, with a concomitant deflection of the lateral commissure (Fig. 3.21 – 3.24, 3.29 – 3.32 cf. for juveniles, Fig. 3.13 – 3.20, 3.25 – 3.28). Dental lamellae and a median septum can be readily discerned in the majority of the smaller specimens; characters that if present in Monticlarella are typically poorly developed (e. g. Owen 1968; Manceñido et al. 2002, p. 1316). (From the palaeobiographic point of view, Monticlarella has not been recorded from Boreal faunas of the Russian Platform or Siberia, whereas several species have been referred to Ptilorhynchia from these regions.) Serial sections were taken of one of the smaller-sized specimens of Ptilorhynchia mclachlani to clarify the relationships among the material (Fig. 5 B). The serial sections show remnants of a dental lamella on the right side of the specimen (Fig. 5 B, section 0.1), a well-developed septalium (0.3 – 0.7) and crura that arch ventrally towards the anterior of the brachiopod (1.0 – 1.6). The crura develop as discrete structures at the junction between the outer hinge plates and the inner hinge plates of the septalial structure (0.5 – 1.0). These serial sections are very similar in overall aspect to those taken from the larger specimen (Fig. 5 A) and both are considered Ptilorhynchia mclachlani. In comparing the serial sections of Ptilorhynchia mclachlani (Fig. 5) with Ptilorhynchia jeletzkyi (Owen 1972, fig. 1) there are similarities in the development of the septalium and the crura on the inner margins of the hinge plates, and the crura then arch ventrally anteriorly. The larger Spitsbergen specimen (Fig. 5 A) did not capture the dental lamellae of the ventral valve, and this is also true when comparing the serial sections of species referred to Ptilorhynchia by Dagys (1968). The presence of well-developed dental lamellae in the ventral valves of the Canadian (Owen 1972), Siberian (Dagys 1968) and Indonesian (MacFarlan et al. 2011) material is a difference from the Spitsbergen material. The ventral umbo of the larger specimen selected for serial sectioning (Fig. 3.21 – 3.24) was damaged, with the outline of dental lamellae visible, and their traces can also be determined in the duplicate cast taken of this specimen. In addition, dental lamellae are clearly visible in the damaged ventral umbones of other specimens. Traces of dental lamellae were not seen in the serial sections and acetate peels (for specimen in Fig. 5 A). This specimen was decorticated and the calcite shell of the dental lamellae apparently lost through decortication or weathering in the umbonal region of the ventral valve. Most of the external shell of the specimen was absent too. Of the serial sections of species described by Dagys, P. lenaensis Dagys (1968, fig. 43) and P. anadyrensis Dagys (1968, fig. 39) appear closest to those of Ptilorhynchia mclachlani (Fig. 5) based on the development of the septalium, hinge plates, and derivation of the crura from the inner margins of the hinge plates. It should be noted that plates 2 and 5 in Dagys 1968 were printed in the wrong order. The taxonomic descriptions and caption for plate 5 refers to P. glabra, P. lenaensis and P. obscuricostata. However, these species are figured on plate 2. Serial sections of the Spitsbergen material (Fig. 5) lack the falciform crura characteristic of the genus Lacunosella recorded from Greenland (Owen 1976, fig. 3). Stratigraphic and geographic distribution. Upper Ryazanian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336254FFB196854704FDBB3103.taxon	description	Fig. 6.9 – 6.17 1968 Ptilorhynchia obscuricostata new species — Dagys, p. 63, pl. 5, fig. 6, 7, text-fig. 42. 2011 v. partim ‘ Lacunosella ’ sp. — Hammer et al., p. 21, table 2.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336254FFB196854704FDBB3103.taxon	materials_examined	Material and occurrence. Seep 3 (PMO 224.915), seep 9 (PMO 224.881, PMO 224.880), seep 12 (PMO 224.884).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336254FFB196854704FDBB3103.taxon	description	Description. Wide triangular outline. Biconvex profile. Broad flat-topped uniplication of the anterior commissure. Smooth shelled with weak or incipient costae developed at the anterior margin, primarily in the fold / sulcus of the anterior commissure. A few growth lines are present. Median septum and dental lamellae are visible. Other internal structures have not been investigated.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336254FFB196854704FDBB3103.taxon	discussion	Discussion. The generally smooth and uniplicate form with the development of costae only towards the margin of the valves was one reason why this material was tentatively referred to ‘ Lacunosella ’ (Hammer et al. 2011), due to its resemblance to L. groenlandica Owen (1976; and in Harper et al. 2005). However, the smooth shell, presence of costae at the valve margins, and broad uniplication of the anterior commissure are also characteristic of Ptilorhynchia obscuricostata (Dagys 1968). Even in the absence of serial sections of the present material, some useful observations can be made. The Spitsbergen specimens do not appear to show the massive shell-thickening of the ventral umbo that Owen observed in serial sections of L. groenlandica (Owen 1976, fig. 3). The presence of distinct dental lamellae in the umbo of the ventral valve is consistent with Ptilorhynchia, but of course not diagnostic of this genus as they are present in many rhynchonellide genera. In L. groenlandica Owen dental lamellae are massively overgrown (Owen 1976, fig. 3). A median septum is present in the dorsal valve of the Spitsbergen material whereas Lacunosella lacks a median septum (e. g. Owen 1976, fig. 3; Manceñido & Owen 2002, p. 1208). Stratigraphic and geographic distribution. Upper Volgian – uppermost Ryazanian, Spitsbergen and Lower Volgian of northern Siberia (Dagys 1968).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB1968540FDFD263308.taxon	type_taxon	Type species. Terebratula depressa var. cyrta Walker, 1868	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB19685418FFBC83740.taxon	description	Fig. 7.5 – 7.8 1976? v. “ Cyrtothyris ” maynci new species — Owen, p. 13, pl. 2, fig. 1 a – c, pl. 3, fig. 4 a – c, text-fig. 7. 2011 v. partim ‘ Cyrtothyris ’ sp. — Hammer et al., p. 20, table 2.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB19685418FFBC83740.taxon	materials_examined	Material and occurrence. Seep 3 (PMO 224.870, PMO 224.904?, PMO 224.919?), seep 8 (PMO 227.428?).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB19685418FFBC83740.taxon	description	Description. Rounded, circular, to gently elongate outline, equibiconvex lateral profile, rectimarginate anterior commissure.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB19685418FFBC83740.taxon	discussion	Discussion. The material from Spitsbergen reaches larger maximum dimensions than “ Cyrtothyris ” maynci described from Greenland (Owen 1976). Broken ventral umbones hamper identification (e. g. Fig. 7.5 – 7.8) and referral to Cyrtothyris must be considered tentative. Owen commented that the Greenland form has an incipient uniplicate anterior commissure. The Spitsbergen specimens show a rectimarginate anterior commissure to possibly weakly uniplicate (Fig. 7.8, anterior commissure damaged). The Greenland material is from the Falskebugt Member (Harper et al. 2005) of Valanginian age whereas the Spitsbergen specimens are from the Upper Volgian. Cyrtothyris has not been recorded from the Upper Jurassic and these specimens may represent a new form. Some of the Spitsbergen brachiopods are morphologically close to Cyrtothyris and Rouillieria. Species referred to these two genera may be morphologically very similar and details of the ventral umbo and profile can be important in distinguishing between them (as discussed by Middlemiss 1976). Several specimens from seep 9 are now considered to be Seductorithyris septemtrionalis; these have an erect beak and lack the produced ventral beak of Cyrtothyris, and are typically less inflated in profile than the latter. However, one specimen from seep 9 (Fig. 7.1 – 7.4; PMO 224.895) with a suberect ventral umbo and incipiently uniplicate anterior commissure, is referred to Cyrtothyris aff. cyrta (Walker). Middlemiss (1976) considers that this species has a rectimarginate to uniplicate anterior commissure. Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336256FFB196854545FC8837F0.taxon	type_taxon	Type species. Terebratula praelonga J. de C. Sowerby in Fitton, 1836	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAF96854284FBEE3433.taxon	description	Fig. 7.9 – 7.20 1976 v. aff. “ Praelongithyris ” borealis new species — Owen, p. 11, pl. 2, fig. 2, text-fig. 6. 2011 v. ‘ Praelongithyris’ sp. — Hammer et al., p. 20, table 2.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAF96854284FBEE3433.taxon	materials_examined	Material and occurrence. Seep 1 (PMO 224.886?, PMO 224.912, PMO 224.907, PMO 224.908?), seep 9 (PMO 227.424 – 425, PMO 224.888 – 890, PMO 224.898), seep 12 (PMO 224.887?, PMO 224.935 – 936).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAF96854284FBEE3433.taxon	description	Description. Elongate rounded to sub-pentagonal outline with dorsal valve longer than wide, evenly biconvex profile with dorsal valve flatter, euseptoidum present, elongate adductor muscle scars. Rounded beak ridges. Lateral commissure gently arched, anterior commissure rectimarginate to incipiently or broadly uniplicate.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAF96854284FBEE3433.taxon	discussion	Discussion. The elongate outline and biconvex profile are comparable to “ Praelongithyris ” borealis Owen. As with Cyrtothyris discussed above, the Spitsbergen specimens reach larger dimensions than the material from Greenland. A uniplicate specimen with an elongate-oval outline (Fig. 7.17 – 7.20) resembles Moutonithyris moutoniana (d’Orbigny). A juvenile specimen (Fig. 7.13 – 7.16) is similar in outline to Cyrtothyris cyrta (Middlemiss 1976, pl. 7, fig. 5) although the profile of the latter has a less inflated dorsal valve; however, the generalized rounded outline is typical for juveniles of many terebratulide species. Praelongithyris? aff. borealis is similar in outline to Taimyrothyris kropotkini (Moisseiev) figured by Dagys (1968, pl. 23, fig. 3). The material recorded by Dagys reaches larger maximum dimensions than the largest Spitsbergen specimen, being L 48; W 34; T 29 mm (Dagys 1968, p. 128) and is more inflated in profile. It is difficult to be certain as to the affinities of the Spitsbergen material without the aid of details of internal structures. However the Spitsbergen specimens, where decorticated, show no trace of crural plates (that would be expected) adjoining the floor of the dorsal valve, typical of the Boreiothyrididae (as in Taimyrothyris, Dagys 1968, fig. 76) and it is concluded that the material is not referable to Taimyrothyris. Dagys recorded Taimyrothyris kropotkini from the Lower Volgian and questionably from the Callovian – Oxfordian. Owen (1976) recorded “ Praelongithyris ” borealis from the Valanginian of Falskebugt, Wollaston Forland, East Greenland. The Spitsbergen material comes from the Upper Ryazanian. Stratigraphic and geographic distribution. Upper Ryazanian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAF96854787FD0E35B3.taxon	type_taxon	Type species. Terebratula michalkowii Fahrenkohl, 1856	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAC96854452FBC8343E.taxon	description	Figs. 7.21 – 7.24, 8.1 – 8.8, 9 1964 cf. Rouillieria michalkowii (Fahrenkohl) — Makridin, p. 249, text-figs. 83, 84, pl. XVI, figs. 7, 8, pl. XVII, figs. 1 – 3. 2011 v. partim ‘ Praelongithyris’ sp. — Hammer et al., p. 20, table 2.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAC96854452FBC8343E.taxon	materials_examined	Material and occurrence. Seep 8 (PMO 227.420, PMO 224.925?, PMO 224.927, PMO 224.930?), seep 13 (PMO 227.421 – 423, PMO 224.901 – 902, PMO 224.905).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAC96854452FBC8343E.taxon	description	Description. Elongate-oval to subtriangular to subpentagonal outline, evenly biconvex profile. Lateral commissure straight to gently ventrally arched. Broad, weak uniplication of the anterior commissure. Serial sections were prepared from one specimen (Fig. 9) which show traces of a pedicle collar (Fig. 9; sections 0.5, 0.7), cardinal process (sections 2.8 – 3.4), and flat and broad hinge plates with ventrally directed crural bases (sections 3.2 – 5.0). The crura develop anteriorly at an acute angle from the hinge plates in a “ v ” - shaped configuration (sections 5.0 – 5.4). Crural processes are high-arched (sections 7.5 – 8.5). The transverse band is flat topped.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336248FFAC96854452FBC8343E.taxon	discussion	Discussion. The material is referred to the loboidothyridoid genus Rouillieria Makridin. However, it has not been possible to determine the length of the flanges of the brachidium with certainty. The flanges of the brachidium were tentatively traced anteriorly to section 18.8 (Fig. 9). Sparry calcite infilling of the brachiopod made tracing the flanges difficult and it is unclear if this represents the maximum length of the loop. The serial sections do not show the exceedingly long anterior flanges on the brachidium seen in Makridin (1964, fig. 83). The sectioned Spitsbergen specimen (Figs. 8.5 – 8.8, 9) is approximately half the length of the largest representatives figured by Makridin and this may account for the possibly shorter flanges. Some species referred to Rouillieria (Makridin 1964) do not appear to attain such large proportions as the type species. Middlemiss (1976, text-figs. 27, 29) provided serial sections of species referred to Rouillieria from the Claxby Ironstone Formation (Valanginian – Hauterivian), Nettleton, Lincolnshire, England — R. tilbyensis (Davidson) and R. walkeri (Davidson). These serial sections show similarities to the Spitsbergen specimen (Fig. 9) in the presence of a cardinal process, relatively flat to flat hinge plates, ventrally projecting crural bases, high arching crural processes, and a high-arched transverse band. The strongly concave juvenile hinge plates considered significant by Middlemiss (1976) have not been observed in the Spitsbergen sections. The Spitsbergen material is similar in outline to the elongate, tear-drop shaped loboidothyridoids Atelithyris crestensis Smirnova, Boreiothyris pelecypodaeformis (Moisseiev), Moisseevia sokolovi Makridin and Spasskothyris rjasanensis Smirnova. Atelithyris crestensis from the Lower Hauterivian of the Russian Platform (Smirnova 1975) tends to have a more oval outline compared to the other species and has a deflected uniplicate anterior commissure. The development of the hinge plates and crural bases is similar to Rouillieria (in Makridin 1964) but lacks the long anterior flanges of the brachidium seen in Rouillieria. However, it would appear that Atelithyris could be derived from Rouillieria. Compared with the other taxa discussed here, Spasskothyris rjasanensis is more elongate in outline and has a broad uniplicate anterior commissure. The internal morphology is distinct, and it is distinguished “ from all Jurassic and Early Cretaceous genera of long-flanged terebratulids by the development of inner hinge plates ... ” (Smirnova 1975, p. 346). However, these inner hinge plates appear to be strongly keeled crural bases, at least initially. The development of these inner hinge plates in Spasskothyris is quite different from that in the Boreiothyrididae, such as in Boreiothyris, where the hinge plates meet in the medial plane of the dorsal valve (see serial sections in Dagys 1968). The internal structures of Moisseevia sokolovi Makridin are unknown but judging from external morphology it appears very close to the genus Rouillieria. Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624BFFAB968546DCFBC8337B.taxon	description	Fig. 8.9 – 8.16 1971 b aff. Rouillieria ovoides (J. Sowerby) — Ager, p. 394, pl. 14, pl. 15, fig. A.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624BFFAB968546DCFBC8337B.taxon	materials_examined	Material and occurrence. Seep 8 (PMO 224.924, PMO 224.926, PMO 224.931 – 932), seep 13 (PMO 224.906, PMO 227.426).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624BFFAB968546DCFBC8337B.taxon	description	Description. Quadrate outline, equally biconvex profile, rectimarginate anterior commissure.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624BFFAB968546DCFBC8337B.taxon	discussion	Discussion. The material is homoeomorphic with other material described herein from Spitsbergen, Uralella? cf. janimaniensis Makridin and Seductorithyris septemtrionalis gen. et sp. nov. From Uralella? cf. janimaniensis it may be distinguished by its smaller size, more rounded hinge line and lesser inflated profile, especially with respect to the dorsal valve. Seductorithyris septemtrionalis has a rounder hinge line, rounder outline, and narrower apical angle of the ventral beak when compared to Rouillieria aff. ovoides; the latter has a more quadrate outline. The Spitsbergen material does not show a posterior shallow sulcation or groove in the dorsal valve. This does appear to be a variable feature (Ager 1971 b; Middlemiss 1976). A rounded keel to the posterior of the ventral valve is considered characteristic (Ager 1971 b; Middlemiss 1976). Ager (1971 b, p. 395) considered some variability in external morphology acceptable within Rouillieria ovoides but questioned the validity of the total number of species referred to Rouillieria by Makridin (i. e., he wondered if there might be fewer, more variable species). The R. ovoides material described by Ager (1971 b) was collected from Spilsby Sandstone Formation glacial erratics in Norfolk, England. Kelly (in Kelly & Rawson 1983) noted that glacial erratics of grey glauconitic Spilsby Sandstone (Kelly’s “ Lithology 2 ” of four erratic lithotypes) contained the ammonite Paracraspedites oppressus Casey, bivalves, and ‘ nests’ [preserved biocoenoses? / clumps sensu Kidwell et al. 1986] of R. ovoides. These erratics are considered to come from the upper Middle Volgian part of the succession (Kelly in Kelly & Rawson, 1983). Middlemiss (1976) discussed the differences between species of Rouillieria from the Claxby Ironstone Formation, Lincolnshire, England. Rouillieria walkeri (Davidson) typically has a sulcate anterior commissure and R. tilbyensis (Davidson) is typically uniplicate, whereas the Spitsbergen material is rectimarginate, more like R. ovoides. There are other subtle morphological differences between R. ovoides and R. tilbyensis (Middlemiss 1976, pp. 69 – 70) and the latter can also be confused with Cyrtothyris cyrta. Smirnova (1975, 1997) referred Sowerby’s Rouillieria ovoides (in Ager 1971 b) to Okathyris, described from the Russian Platform (Smirnova 1975). However, she did not give in detail the reasons for this assignation. The hinge plates of Rouillieria ovoides figured by Ager (1971 b, fig. 1) are narrow compared with R. michalkowii (Makridin 1964, fig. 83). Ager did show that the flanges of the brachidium for R. ovoides from England extended at least 17.8 mm beyond the crest of the transverse band (located 20.4 mm from the posterior of the sectioned specimen), indicating long loop flanges. These flanges are proportionately more comparable in length with those recorded for Rouillieria (Makridin 1964, fig. 83) whereas the loop flanges for Okathyris are shorter (Smirnova 1975, figs. 1, 3). In serial sections of Okathyris chevkinensis Smirnova (1975, fig. 1) and O. sokolovi Smirnova (1975, fig. 3) the loop flanges anterior of the transverse band are approximately 6 – 7 mm in length. The brachidial flanges for Rouillieria cf. michalkowii (Fig. 9 herein) are also shorter than those for the genus in Makridin (1964) and have already been discussed under that species. Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAB9685419FFBC8365B.taxon	description	Fig. 8.17 – 8.20 1975 aff. Rouillieria rasile new species — Smirnova, p. 350, pl. X, fig. 3.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAB9685419FFBC8365B.taxon	materials_examined	Material and occurrence. Seep 8 (PMO 224.929).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAB9685419FFBC8365B.taxon	discussion	Discussion. One damaged specimen that has a similar outline to the specimen figured by Smirnova (1975). The Spitsbergen specimen has a slightly more shouldered appearance at the hinge line compared to Smirnova’s figured specimen. The long, very wide ventrally concave hinge plates and apparently relatively small crural bases (Smirnova 1975, fig. 8) do point to this species as having internal structures that are atypical of Rouillieria. However, in the diagnosis for Rouillieria Lee et al. (2006, p. 2098) state “ outer hinge plates broad ”. The diagnosis for the genus also refers to crural bases that form lateral umbonal cavities reaching the valve floor (e. g. serial sections of R. michalkowii in Makridin (1964, fig. 83 )). However, these lateral umbonal cavities presumably develop due to secondary shell overgrowth and therefore depend on the growth stage of the sectioned specimen. It is probable that these cavities are more likely to develop in maturing or gerontic individuals (or they may even become infilled with secondary shell material in the latter). Smirnova described Rouillieria rasile from Chevkino Village, Ryazan Province, Russia and it was recorded from the “ Berriasian, Ryazan horizon ” (Smirnova 1975, p. 351). Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAB9685447FFD6E368B.taxon	type_taxon	Type species. Terebratula strogonofi d’Orbigny, 1845	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAA9685450AFBC83193.taxon	description	Fig. 10.1 – 10.8 1964 cf. Uralella jani - maniensis new species — Makridin, p. 258, text-figs. 87, 88, pl. XIX, fig. 2, pl. XX, fig. 1.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAA9685450AFBC83193.taxon	materials_examined	Material and occurrence. Seep 3 (PMO 224.916?, PMO 224.921, PMO 224.928, PMO 224.938 – 939?, PMO 224.941, PMO 224.944).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624CFFAA9685450AFBC83193.taxon	discussion	Discussion. Specimens have a rounded quadrate outline and inflated profile that is suggestive of Uralella Makridin. The outline of the specimens compare to that of U. janimaniensis Makridin and U. strogonofi (d’Orbigny) in Makridin (1964, given as strogonowii, p. 254 and in text and plate captions; strogonovii in table 3). The rounder hinge line of the latter may help to differentiate these two forms. The outline is also reminiscent of specimens referred to Rouillieria aff. ovoides herein. Makridin (1964) recorded Uralella janimaniensis from the Upper Volgian. Uralella strogonofi was recorded from the Lower Volgian (Dagys 1968). A single incomplete specimen that has a highly inflated profile is suggestive of Uralella. This specimen is tentatively referred to Uralella sp., specimen number PMO 224.943, from seep 3, Upper Volgian. Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624DFFAA96854419FCFC37CA.taxon	diagnosis	Diagnosis. Round outline, with the dorsal valve almost circular. Profile equi- to gently ventribiconvex. Smooth shell with growth lines. Erect beak. Ventral valve umbo keeled. Lateral commissure straight, anterior commissure rectimarginate. Internal structures: cardinal process present, flat / horizontal and wide hinge plates deflect dorsally, crural bases develop on inner margin of hinge plates, clubbed and weakly deflected dorsally. Transverse band curved, low-arched, and approximately at mid-point of brachidium, anterior flanges long.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624DFFAA96854419FCFC37CA.taxon	etymology	Etymology. For the deceptive way that homoeomorphy among brachiopods may mask their affinities (deceiver — latin seductor). Occurrence. Uppermost Ryazanian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624DFFAA96854419FCFC37CA.taxon	type_taxon	Type species. Seductorithyris septemtrionalis sp. nov.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	description	Figs. 11.1 – 11.16, 12 2011 v. partim ‘ Cyrtothyris ’ sp. — Hammer et al., p. 20, table 2, fig. 7. S.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	materials_examined	Material and occurrence. Holotype: PMO 224.896; paratypes: PMO 217.198, PMO 224.892 – 893, PMO 224.911, PMO 224.913, PMO 227.427?, PMO 227.430. All from seep 9. Type locality. Knorringfjellet, central Spitsbergen, N 78 ° 18 ’ 49.9 ” E 16 ° 10 ’ 58.9 ”.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	diagnosis	Diagnosis. As for the genus.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	etymology	Etymology. For the northern high-latitudes that Spitsbergen occupies (septem triōnēs [also septentrional]: the seven stars of the constellation of Ursa Major [the Great Bear, or the Plough] — a constellation visible in the northern hemisphere throughout the year and a useful aid to finding North; also “ of the north ” or “ north wind ”).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	description	Dimensions of the holotype. PMO 224.896 — Length 33.7 mm, width 29.8 mm, thickness 16.1 mm. Description. Length slightly greater than width, rounded outline, with the dorsal valve almost circular. Biconvex profile with the dorsal valve tending to be flatter, but not necessarily. Smooth shell with growth lines. Erect beak. Ventral valve umbo has a broad round keel. Lateral commissure straight, anterior commissure rectimarginate. Cardinal process developed (Fig. 12, sections 0.7 – 1.2 mm), flat, horizontal and wide hinge plates deflected dorsally (sections 1.2 – 2.3), crural bases develop on inner margin of hinge plates (sections 1.6 – 2.3) and have a clubbed appearance initially (section 1.8). Crura are initially weakly deflected dorsally (sections 2.3 – 2.7). Transverse band is curved and low-arched (section 6.6, this is approximately at the mid-length of the brachidium, based on the distance the loop was traced), anterior flanges of the brachidium extend significantly beyond the transverse band (at least 5.8 mm). Loop traced to at least 11.4 mm from initial section through brachiopod (ventral umbo of sectioned specimen is damaged).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C33624EFFA696854284FBA43193.taxon	discussion	Discussion. The beak of the ventral valve is erect in Seductorithyris septemtrionalis whereas in “ Cyrtothyris ” maynci from East Greenland the beak is slightly produced, suberect, and with a massive umbo dominated by a large circular foramen (Owen 1976). The outline of the Spitsbergen material is comparable to that of rounded terebratulide species discussed by Middlemiss (1976) from the Claxby Ironstone Formation of Lincolnshire, England, such as Rouillieria tilbyensis (Davidson) and Cyrtothyris cyrta (Walker). Both of these species show rounded and elongated morphotypes and appear however to have a more massive pedicle foramen and may develop a uniplicate anterior commissure, which helps to distinguish them from Seductorithyris septemtrionalis. The rounded outline of Seductorithyris septemtrionalis is similar to that of Pinaxiothyris campestris (Dagys 1968, pl. 10, figs. 1 – 3), although the latter appears to have a slight elongation to its outline, reaching a greater size. One specimen from Spitsbergen is tentatively referred to Pinaxiothyris campestris Dagys (Fig. 13.1 – 13.4). It is similar in outline to an elongate specimen figured by Dagys (1968, pl. 10, fig. 4). The development of the cardinal process, flat hinge plates, crura, crural processes, and transverse band show similarities between the internal characters of Seductorithyris septemtrionalis (Fig. 12) and Pinaxiothyris (Dagys, 1968, fig. 52). The latter has hinge plates that are not as wide and the crural bases do not show the slight dorsal deflection seen in Seductorithyris. Another genus considered during classification of this species was Moutonithyris, characterized by distinctive horizontal hinge plates and crural bases derived from the inner margins of the hinge plates. However, the crescentshaped attached crura seen in Moutonithyris (e. g. Middlemiss 1976; Nekvasilova 1980) are different from the clubshaped crural bases of Seductorithyris. In addition, Moutonithyris has a lower-arched transverse band compared to that of Seductorithyris, and does not appear to share the long flanges of the brachidium seen in the latter. The nature of the horizontal hinge-plates with the rounded crural bases could be described as clubbed (after Cox & Middlemiss 1978) due to secondary overgrowth (Fig. 12, section 1.8). The crura project weakly dorsally and do not conform to those of any described Mesozoic terebratulide. The hinge-plates are short in length (sections 0.7 – 2.7) and the loop develops rapidly to the crural processes (section 4.0) before reaching the transverse band at 6.6 mm. The loop flanges were traced for another 5.8 mm to 11.4 mm. The sectioned specimen might represent a juvenile specimen because of its size and hence also in its loop development. The ontogenetic development of the brachidium can hardly be said to be well understood among terebratulide brachiopods, and even less so perhaps the relationship between the hinge plates and the crural bases. However, these elements of the cardinalia appear stable in juvenile brachiopods judging from serial sections of growth-series of brachiopods (e. g. Dagys 1972; Smirnova 1973 (for rhynchonellides), 1984, 2008; see also Lee et al. 2001 and Tort & Laurin 2001). In Seductorithyris the crural bases develop as rounded to cuneate processes that project weakly dorsally, or at least do not project ventrally while attached to the hinge plates, thereby making a unique configuration that suggests a new brachiopod genus that is certainly distinct from its contemporaries. This configuration of the clubbed crura is quite different from the pendant or keeled crural bases typical of representatives of the terebratuloid Gibbithyris or the loboidothyridoid Placothyris. A specimen from seep 3 (Fig. 13.5 – 13.8; Upper Volgian) is comparable to Placothyris kegeli from Wollaston Forland, East Greenland (Fig. 13.9 – 13.12; Valanginian, infilling matrix is a red micrite). Stratigraphic and geographic distribution. Uppermost Ryazanian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336241FFA69685412AFD5233D5.taxon	type_taxon	Type species. Terebratula orbis Quenstedt, 1858	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336241FFA4968541F5FBA43103.taxon	description	Fig. 13.13 – 13.20 1976? v. “ Zittelina ” sp. — Owen, p. 16, pl. 3, fig. 1. 2011 v. ‘ Zittelina ’ sp. — Hammer et al., p. 20, table 2, fig. 7 T.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336241FFA4968541F5FBA43103.taxon	materials_examined	Material and occurrence. Seep 9 (PMO 217.200, PMO 224.869, PMO 224.885).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336241FFA4968541F5FBA43103.taxon	description	Description. Round and weakly subpentagonal outline, somewhat ventribiconvex profile, and rectimarginate, to possibly incipiently sulcate anterior commissure. Dental lamellae are present in the ventral valve umbo and a median septum is present in the dorsal valve indicating a long-looped terebratellidine. Decorticated specimens (Fig. 13.13 – 13.16 and Hammer et al. 2011, fig. 7 T) show the presence of dental lamellae and a median septum. A smaller specimen is a possible juvenile (Fig. 13.17 – 13.20).	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
466F6C336241FFA4968541F5FBA43103.taxon	discussion	Discussion. Owen (1976, pl. 3, fig. 1) figured a specimen from the Valanginian of Wollaston Forland, East Greenland that has a pentagonal outline, inflated biconvex profile, and ventrally deflected anterior commissure but with no obvious concomitant sulcation developed on the dorsal valve. The specimen from Spitsbergen has a round outline, rectimarginate anterior commissure, and biconvex profile but with a lesser degree of inflation compared to the Greenland specimen. The relationship between the Greenland and Spitsbergen material is difficult to assess at present as only one specimen was identified from Greenland and only two mature specimens are known from Spitsbergen. The differences in outline, profile and commissure make it unlikely that the forms from Greenland and Spitsbergen are conspecific. Given the predominantly Boreal aspect of the fauna from Spitsbergen it may be that this form is allied to Rugitela Muir-Wood (considered to be the senior synonym of Russiella Makridin (Baker 2006 )). The specimens lack the sulcate dorsal valve and sulcus of the anterior commissure seen in Rugitela hippopus (Roemer) that has been recorded from East Greenland (Harper et al. 2005).? Rugitela sp. (Owen 1976) was put in synonymy with Rugitela hippopus (Harper et al. 2005) but this seems rather unlikely as the latter is elongate-quadrate in outline and weakly sulcate. The Early Cretaceous age of this material suggests that an affinity to Zittelina rather than Kingena Davidson is more likely. However, both genera are very similar in external morphology (discussed by Owen 1970). The granular shell ornament considered characteristic of Kingena has not been observed, although well-developed endopunctation has. The incipient (?) sulcation of the anterior commissure (Fig. 13.16, 13.20) might suggest an affinity to Zittelina in contrast to faint uniplication that could suggest Kingena (based on generic diagnoses given by MacKinnon et al. 2006; although a rectimarginate anterior commissure is common to both genera). Species referred to Dzirulina Nutsubidze (considered a senior subjective synonym of Belothyris Smirnova by Sandy et al. 1995) typically have a more elongate outline than for Zittelina and Kingena (discussed by Owen 1970). Stratigraphic and geographic distribution. Uppermost Ryazanian of Spitsbergen.	en	Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne, Little, Crispin T. S. (2014): Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard. Zootaxa 3884 (6): 501-532, DOI: http://dx.doi.org/10.11646/zootaxa.3884.6.1
