taxonID	type	description	language	source
1D2F9F2B9A30FFC4FC4FFE82DBDCBBFB.taxon	type_taxon	TYPE SPECIES. — Pontosphaera bigelowi Gran & Braarud, 1935 by subsequent designation of Deflandre (1947).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC4FC95FDE2DA8DBEE5.taxon	distribution	DISTRIBUTION. — This taxon is recorded in several middle Eocene outcrop and borehole sections in Belgium (Steurbaut in Herman et al. 2001 and in Smith et al. 2004; Steurbaut et al. 2015). In the Mont-des-Récollets section it consistently ranges from the uppermost part of the Brussel Sand Formation (base of Unit B 4) to the base of the Wemmel Sand Member. In terms of calcareous nannoplankton zones, its occurrence encompasses the upper part of NP 14 and the lower part of NP 15, as it appears to do in the Paris Basin (Aubry 1983, 1986) and the Aquitaine Basin (Lin et al. 2017). In the Paris Basin it seems to recur in the Bartonian (Chavençon Marls: NP 17 or NP 18, Aubry 1983: pl. 8, figs 10 - 11), although this has not been observed in the other basins.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC4FC95FDE2DA8DBEE5.taxon	discussion	DISCUSSION B. stylifera differs from all up to now known Braarudosphaera taxa by its very high slightly tapering outline, resembling a pentagonal pyramid with truncated top, the margin sides of which are often slightly bowed inward (Fig. 18 B). Both pentagonal ends can clearly be observed viewed from above when over-focusing and under-focusing with the microscope.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC4FC6AFA7ADC98BFF3.taxon	type_taxon	TYPE SPECIES. — Lanternithus minutus Stradner, 1962 by original designation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC6FC7FF9DADD3BB87E.taxon	description	(Fig. 18 E)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC6FC7FF9DADD3BB87E.taxon	distribution	DISTRIBUTION. — L. minutus is biostratigraphically significant, despite its rather long range (upper lower Eocene-lower Oligocene). In the North Sea Basin it has a synchronous lowest consistent occurrence (LCO) within the upper middle of NP 14: from the base of unit B 4 (upper part of the Brussel Sand Formation) at the Mont-des-Récollets, where its occurrence coincides with the LO of Nummulites laevigatus, from about 2.5 to 3 m above the base of the ‘ Glauconie Grossière s. s. ’ (as defined by Blondeau 1980) in the Paris Basin (appearance level of Blackites inflatus) and from the Nummulites laevigatus Bed (F 6) at Bracklesham Bay, UK. Isolated specimens occur earlier. In the Belgian Basin they are known from many localities within the lower middle of unit B 3, which corre- lates with lower middle NP 14. A single specimen is known from the lower part of Unit A 4 (top of the Aalter Sand Formation) in the Vlakte van de Raan borehole, one from the turritellid level at Whitecliff Bay (at 225 m above the base of the London Clay, dixit D. Curry), and two from the upper part of the ‘ Chaumont-en-Vexin sands’ in the Paris Basin, all attributable to the base of NP 14. In west Kazakhstan (e. g. Aktulagay), L. minutus seems to appear still earlier (within the middle of NP 13) (King et al. 2013).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A30FFC6FC7FF9DADD3BB87E.taxon	discussion	DISCUSSION This small nannolith with a box-like shape has a very distinctive morphology and optical interference pattern, allowing unambiguous and easy recognition.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	description	(Fig. 19 B, C) urn: lsid: zoobank. org: act: B 9 D 3 C 0 AA- 736 A- 4785 - 9 B 04 - D 58126482 E 0 E	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	materials_examined	HOLOTYPE. — Fig. 19 B (IRSNB b 7121) (negatives stored in the collections of the RBINS). PARATYPES. — 1 figured specimen (d = 9 µm) from the upper part of the Aalter Sand Formation in the Vlakte van de Raan BH, 79.95 m depth (Fig. 19 C) (IRSNB b 7122).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	diagnosis	DIAGNOSIS. — Circular coccoliths consisting of two appressed shields and including a central disk covered by a series of radially oriented calcite laths and a smaller outer rim with numerous almost indistinct slightly curved elements. Only the outer rim is highly birefringent in cross-polarized light.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	etymology	DERIVATIO NOMINIS. — Refers to the total range of this species, which seems to be restricted to the earliest part of the Lutetian.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	materials_examined	LOCUS TYPICUS. — Vlakte van de Raan borehole, 81.45 m depth, 51 ° 29 ’ 08 ” N, 03 ° 09 ’ 50 ” E. STRATUM TYPICUM. — Aalter Sand Formation, upper part of Oedelem Sand Member; base of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	description	DIMENSIONS. — Diameter = all around 9 µm (holotype: d = 9 µm). DISTRIBUTION. — Luminocanthus eolutetiensis n. gen., n. sp. is known from boreholes in the Belgian sector of the North Sea (SEWB and Vlakte van de Raan, see Appendix 1), where it seems to be retricted to the top of the Aalter Sand Formation (base of NP 14). Up to now it has not been recorded in coeval deposits from onshore Belgium. DESCRIPTION These medium-sized (d = c. 9 µm) rather thick subcircular forms consist of a prominent outer rim including numerous (probably c. 50) vaguely visible elements and an inner area with radially oriented elements. Both zones are sharply delimited in distal view. The outer rim is rather thick and exhibits high birefringence under crossed nicols, especially the outer rim of the proximal shield (Fig. 19 Ba). The inner area is only faintly birefringent, although shows a clear extinction cross with laevogyre curvation in distal view. It widens and is somewhat blurry in the outer rim.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FF3BF8F4DA1DBC00.taxon	discussion	D ISCUSSION This taxon differs from L. plenilutetiensis n. gen., n. sp. (Fig. 19 G-J) by the configuration of the outer rim and the central area. The outer rim of L. eolutetiensis n. gen., n. sp. is much more elevated, smaller and sharply separated from the central area. This rim is also highly birefringent as in L. plenilutetiensis n. gen., n. sp., but contrarely to the latter, the central area remains only faintly illuminated in cross-polarized light. The extinction lines are rather sharp in the central area and become wider and vague in the outer rim.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FEFDFD13DEB5BCD7.taxon	description	urn: lsid: zoobank. org: act: 872 DDF 1 A- 35 F 0 - 4369 - 9812 - 7 B 1 D 5 A 0 DF 8 F 7	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FEFDFD13DEB5BCD7.taxon	type_taxon	TYPE SPECIES. — Luminocanthus plenilutetiensis n. sp.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FEFDFD13DEB5BCD7.taxon	etymology	DERIVATIO NOMINIS. — Refers to the bright outer rim of these fairly thick circular coccoliths (luminus = light, canthus = ‘ rim of the wheel’), when viewed in cross-polarized light.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FEFDFD13DEB5BCD7.taxon	diagnosis	DIAGNOSIS. — This new genus is erected to include circular coccoliths consisting of a non-perforated, practically closed, central disk and a much smaller outer rim with many slightly bent elements (n> 30). The outer rim is always highly birefringent in cross-polarized light, the central disk sometimes (e. g. in the type species).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC6FEFDFD13DEB5BCD7.taxon	discussion	DISCUSSION Four species are currently included in this genus (in stratigraphical order): L. eolutetiensis n. gen., n. sp. from the lowermost Lutetian of the Belgian Basin (see below), L. plenilutetiensis n. gen., n. sp. from the lower middle Lutetian of the Belgian Basin and the Paris Basin (see below), L. hirsitus (Müller, 1970) n. comb. from the lower middle Oligocene of Belgium and Germany (Müller 1970; Steurbaut 1986) and L. hoerstgensis (Müller, 1970) n. comb from the upper middle Oligocene of Northern Germany (Müller 1970). Both Oligocene species have been synonymized with the upper Eocene species Cribrocentrum reticulatum (Gartner & Smith, 1967) (cf. Nannotax 3, http: // www. mikrotax. org / Nannotax 3 / index. html), although erroneously, as these taxa are fundamentally different (e. g. in construction of distal shield and number of elements in the shields).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	description	(Fig. 19 G-J) urn: lsid: zoobank. org: act: AEAC 0171 - 1130 - 4 C 9 B-B 8 B 0 - CAD 63145 C 860	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	materials_examined	HOLOTYPE. — Fig. 19 G (IRSNB b 7126) (negatives stored in the collections of the RBINS). PARATYPES. — 2 figured specimens from the Brussel Sand Formation: 1 from from Vossem, Unit B 3 (Fig. 19 H) (IRSNB b 7127) and 1 from the Knokke BH (Steurbaut 1990: pl. 1, fig. 9), 71.95 m depth (Fig. 19 J) (IRSNB b 7129); 1 from Prémontré (sample 12), Paris Basin, base of the ‘ Glauconie Grossière s. s. ’ (Fig. 19 I) (IRSNB b 7128). DIAGNOSIS. — Circular coccoliths consisting of two closely appressed shields, including a central disk covered by a series of irregularly oriented calcite laths and a smaller outer rim with numerous conspicuous slightly curved elements. Both areas are highly birefringent in cross-polarized light.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	etymology	DERIVATIO NOMINIS. — Refers to its position within the Lutetian, as its lowest occurrence is at the base of the coarse-grained sand facies of the Lutetian (base of Brussel Sand Formation in Belgium, base of ‘ Glauconie grossière s. s. ’ in the Paris Basin), which overlie the basal Lutetian fine-grained glauconitic sand facies, as identified in many outcrop and borehole sections in Belgium (Unit A 4) and at Chaumont-en-Vexin (‘ Chaumont-en-Vexin sands’) in the Paris Basin.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Brussel Sand Formation, base of Unit B 3 (122.26 - 122.21 m); lower middle part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	description	DIMENSIONS. — Diameter = 5.0 to 9.6 µm (holotype: d = 8.4 µm). DISTRIBUTION. — Luminocanthus plenilutetiensis n. gen., n. sp. is known from many Lutetian outcrop and borehole sections in the southern North Sea Basin, including the historical stratotype area (e. g. from the base and the upper part of the ‘ Glauconie Grossière s. s. ’ at Prémontré (Fig. 19 I) and Margival respectively). In Belgium it is consistently present from the base (Unit B 1) up to the top of the Brussel Sand Formation (e. g. Isnes quarry) and seems to be restricted to it. At the Mont-des-Récollets there is a major influx (also the first occurring specimens) at the base of Unit B 2 b. It has been recorded in Unit C 2 (sample 50.8 m) of the Aktulagay section, attributed to NP 14, although in very low numbers (Steurbaut in King et al. 2013). DESCRIPTION These rather small (generally around 7 µm in diameter) and thick circular coccoliths consist of two closely appressed shields. The distal shield has a prominent outer rim including 32 to 38 elements, displaying laevogyre element curvature in distal view (Fig. 19 G), and an inner concave area with less-well visible irregularly oriented elements. Both zones are not sharply delimited in distal view and show high birefringence under crossed nicols. The conspicuous swastika-like extinction cross has a laevogyre outline in the central area in distal view. It widens and is somewhat blurry in the outer rim.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A32FFC1FCA2F99EDE65BCE6.taxon	discussion	DISCUSSION The extinction figure of the type species is quite similar to that of L. hirsitus (Müller, 1970) n. comb. from the lower Middle Oligocene of Belgium, suggesting a close relationship. However, coccoliths of the latter seem to have a much broader outer rim. The differences with L. eolutetiensis n. gen., n. sp. are discussed above.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC1FC4CFF2DDA5ABE11.taxon	distribution	DISTRIBUTION. — In the southern North Sea Basin the LO of D. praebifax slightly precedes the LO of Discoaster sublodoensis (e. g. at Aalter, beds 4 to 9: Steurbaut & Nolf 1989, erroneously interpreted as D. bifax), and is, consequently, within the top of NP 13. At the Mont-des-Récollets, D. praebifax first occurs in the upper part of the Aalter Sand Formation (lower NP 14) and ranges up to the base of the Wemmel Sand Member. Its earliest record is from Aktulagay (west Kazakhstan), where it appears at the base of NP 13 (King et al. 2013).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC1FC4CFF2DDA5ABE11.taxon	discussion	DISCUSSION In their investigation of middle Eocene calcareous nannofossil associations of two DSDP holes, Wei & Wise (1989 b) separated the discoasters with high numbers of rays (16 - 27) and one prominent central stem from similar forms with fewer rays (10 - 15), known as Discoaster bifax Bukry, 1971, to which they previously have been attributed (e. g. in Perch- Nielsen 1985; Aubry 1986). The populations with high ray numbers were grouped into D. praebifax, which, in view of its morphological similarities and stratigraphic relationship, was suggested to be the ancestor of the latter. The number of rays in the Mont-des-Récollets specimens ranges between 20 and 22, evidencing the presence of D. praebifax only.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC0FC82FBAEDC34BBAC.taxon	description	(Fig. 18 I-M)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC0FC82FBAEDC34BBAC.taxon	distribution	DISTRIBUTION. — Typical 5 - rayed specimens. of Discoaster sublodoensis are recorded at the base of Unit A 4 in the well-preserved assemblages of the Vlakte van de Raan borehole and at the base of the ‘ Chaumont-en-Vexin sands’ in the Paris Basin, although always in very low numbers. They co-occur with numerous 6 - rayed specimens with straight rays (considered herein as ‘ late form’ of D. lodoensis) and other, although more rarely, 6 - rayed forms with straight rays without ridges (D. strictus and alies). In the less well preserved assemblages of the Mont-des-Récollets the typical 5 - rayed specimens seem to pop up only from the middle of Unit A 4. D. sublodoensis remains quite rare within the totality of its range at the Mont-des- Récollets, although it is consistently found up to the top of Unit B 3. It is extremely rare from the base of B 4 onward and has not been observed in the base of the overlying Lede Sand Formation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC0FC82FBAEDC34BBAC.taxon	discussion	DISCUSSION Specimens from the Paris Basin and the Hampshire Basin (Aubry 1986) are almost identical to these from Belgium, but slightly differ from the holotype (Lodo Formation, California, Bramlette & Sullivan 1961: pl. 12 / 6), material collected in DSDP holes (Wei & Wise 1989 a: fig. 3 / 2), and some of the forms recorded at the Ypresian / Lutetian GSSP in Spain (Molina et al. 2011: plate 1, fig. 2). The latter are marked by a rather wide central area rapidly narrowing and extending into 5 or 6 (exceptionally 7) slender rays and by ray margins, which are slightly bowed inwards near the base of each ray. The area where the rays meet is not sharp and angular, but, on the contrary, distinctly rounded (see Fig. 18 M). The rays of the North Sea Basin specimens have triangular free ends, with straight margins, which meet at clear angles (see Fig. 18 I-K). The central disk, which is marked by a small low stem and low crests along the margin of the rays, ending at the interstices between the rays, is similar within the total population range of the species.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A35FFC1FEDBF885DE6ABDF4.taxon	type_taxon	TYPE SPECIES. — Discoaster pentaradiatus Tan Sin Hok, 1927 (by original designation).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FF70FE03DDDBBEC4.taxon	description	(Fig. 18 O-R)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FF70FE03DDDBBEC4.taxon	distribution	DISTRIBUTION. — D. wemmelensis is consistently recorded in Lutetian nannofossil assemblages worldwide, although generally in low concentrations (Perch-Nielsen 1985; Aubry 1986; Varol 1998; Tori & Monechi 2013; Franceschi et al. 2015). It occurs in very low numbers at the Mont-des-Récollets, from the base of the Brussel Sand Formation (its LO is at the base of Unit B 1, lower NP 14) up to the base of the Wemmel Sand Member (middle NP 15). A few isolated specimens have been recorded slightly earlier at the top of the Aalter Sand Formation in boreholes north of the Mont-des- Récollets, but not at the Mont-des-Récollets itself (2 in the Vlakte van de Raan borehole and 1 specimen in the Oedelem borehole, a few meters above the base of NP 14 as defined herein). This might not correspond to its total range, as in Belgium D. wemmelensis is known to occur throughout the Wemmel Sand Member (middle NP 15) up to the Ursel Clay Member (base of NP 16) (Steurbaut 1986).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FF70FE03DDDBBEC4.taxon	discussion	DISCUSSION This small (d = c. 5 µm) discoaster with serrate outline is marked by two superimposed cycles of elements, consisting of 20 to 30 wedge-shaped rays, and lacks a central knob.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	description	(Fig. 18 F, G) urn: lsid: zoobank. org: act: BC 34435 D-E 488 - 4 BDF-A 956 - 093 AA 0 FA 4 C 44	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	materials_examined	HOLOTYPE. — Fig. 18 G (IRSNB b 7099) (negative stored in the collections of the RBINS). PARATYPES. — 1 from the “ Chaumont-en-Vexin sands ” at Chaumonten-Vexin (sample CHA 11, 0.55 m above the base of the Lutetian (Fig. 18 F, IRSNB b 7098) and 2 non-figured specimens from the base of Unit A 4 of the Aalter Sand Formation (Mont-des-Récollets: 114.85 m and Vlakte van de Raan borehole: 82.95 m depth).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	diagnosis	DIAGNOSIS. — Circular fragile structure, slightly conical in side view, consisting of a series of concentric rings, supported by 17 to 19 radially oriented pillars, resembling a spider’s web.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	etymology	DERIVATIO NOMINIS. — The species name is a combination of Cecile, the Christian name of the first author’s spouse, who passed away recently, and of Ella-Noor, the first name of his grand-daughter.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	materials_examined	LOCUS TYPICUS. — Leuven borehole, 23.70 m depth, 50 ° 53 ’ 24.36 ” N, 4 ° 42 ’ 33.69 ” E. STRATUM TYPICUM. — Brussel Sand Formation, base of Unit BE; base of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	description	DIMENSIONS. — Diameter = 13 to 14 µm (holotype: d = 14 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	distribution	DISTRIBUTION. — At the Mont-des-Récollets it is known from 1 specimen in the upper part of the Aalter Sand Sand Formation (lower Unit A 4, base NP 14). It has also been recorded in the Vlakte van de Raan borehole at the top of the Aalter Sand Formation (upper Unit A 4, 82.95 m depth, lower NP 14) and in the Leuven-Artois borehole (base of Unit BE, base of NP 14). It has been identified in several samples of the lower part of the ‘ Chaumon-en-Vexin sands’ at the Darcy site at Chaumont-en-Vexin (Steurbaut, unpublished information). These records led us to conclude that the LO of M. cecellanoriae n. sp. is a major stratigraphical marker, as it is coincident with the base of NP 14 and the base of the historical Lutetian stratotype.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	description	DESCRIPTION This circular slightly inflated body consists of a number of (generally three) peripheral concentric rings surrounding a central network, which are supported by 17 to 19 radially oriented pillars. This concentric structure, which resembles a spider’s web, shows no birefringence under crossed nicols.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FEC3F998DB3BBFC3.taxon	discussion	DISCUSSION This taxon has many similarities with Martiniaster fragilis, but instead of the 12 radially arranged peripheral ridges, it has a much larger number of radial pillars (generally between 17 and 19), which are less prominently developed. It appears to be also less globular.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FF15FA9BDD1EBC07.taxon	description	urn: lsid: zoobank. org: act: D 80 B 2 B 4 E-D 12 E- 4 D 53 - 8 DBB- 5081853 FBC 7 D	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC0FF15FA9BDD1EBC07.taxon	materials_examined	TYPE SPECIES. — Coronaster fragilis Martini, 1961 by subsequent designation of Loeblich & Tappan (1963).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC3FC7CF9D8DE5BBB8E.taxon	description	(Fig. 18 N)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC3FC7CF9D8DE5BBB8E.taxon	distribution	DISTRIBUTION. — This species is consistently but rarely present in the shallow marine Middle Eocene strata from the North Sea Basin. At the Mont-des-Recollets it ranges from the upper part of the Brussel Sand Formation (Unit B 4) to the middle of the Lede Sand Formation. This does not represent its total range, as in other Belgian localities it is known to occur up to the Asse Clay Member (upper NP 15) (Steurbaut 1986). Additional occurrences in adjacent basins are from the lower Lutetian sands at Grand-Alléré (NP 14) in the Paris Basin (see Appendix 1) and from Fisher Beds 20 and 21 in the Hampshire Basin (NP 15) (Aubry 1983). Hence, its occurrence seems to be restricted to upper NP 14 and NP 15.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A34FFC3FC7CF9D8DE5BBB8E.taxon	discussion	DISCUSSION With its globular outline consisting of 12 radially arranged peripheral ridges and several large central openings this taxon is easily recognisable.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FC93FC80DBF1BF28.taxon	description	(Fig. 20 S)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FC93FC80DBF1BF28.taxon	distribution	DISTRIBUTION. — At the Mont-des-Récollets it is known from Unit B 4 at the top of the Brussel Sand Formation and in the overlying Lede Sand Formation, up into the base of the Wemmel Sand Member. It rarely occurs elsewhere in the Lede Sand Formation (e. g. recorded at Balegem, Oosterzele, etc.).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FC93FC80DBF1BF28.taxon	discussion	DISCUSSION Three rather long thin arms with bifurcating endings, which are lined with a narrow weblike fringe.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FC6CFD80DB62B92F.taxon	description	urn: lsid: zoobank. org: act: 9 DFE 30 A 4 - E 474 - 4861 - 8 FDD-DE 1 A 1491 F 8 D 4	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FC6CFD80DB62B92F.taxon	type_taxon	TYPE SPECIES. — Discoaster bramlettei Martini, 1958 by subsequent designation of Stradner (1961).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FECAFE2CDE3BB893.taxon	description	urn: lsid: zoobank. org: act: 780 A 5297 - 7230 - 4 AAE-A 3 EE- 0 C 6992 F 3 B 1 E 6	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FECAFE2CDE3BB893.taxon	type_taxon	TYPE SPECIES. — Trochoaster simplex Klumpp, 1953 (by original designation).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	description	(Fig. 18 W-Y) urn: lsid: zoobank. org: act: BEE 661 BF- 859 D- 4 C 27 - AC 92 - BF 41326 F 94 A 1	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	materials_examined	HOLOTYPE. — Fig. 18 W (IRSNB b 7115) (negative stored in the collections of the RBINS). PARATYPES. — 2 figured specimens; 1 from the Vilvoorde borehole at 5.80 m depth (d = 15 µm) (Fig. 18 X) (IRSNB b 7116) and 1 from the middle part of the Oedelem Sand Member (Aalter Sand Formation) in the Oedelem BH (11.70 m) (d = 15 µm) (Fig. 18 Y) (IRSNB b 7117); both base of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	diagnosis	DIAGNOSIS. — Six-rayed body, enterily covered with bumps, and marked by strong median ridges along the rays, which are connected with a central circular ring.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	etymology	DERIVATIO NOMINIS. — The species name refers to the presence of numerous small bumps popping up all over this robust six-rayed holococcolith.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	materials_examined	LOCUS TYPICUS. — Quarry at Chaumont-en-Vexin, sample 16, Paris Basin; c. 49 ° 15 ’ 33.59 ” N, 1 ° 52 ’ 44.20 ” E. STRATUM TYPICUM. — ‘ Chaumont-en-Vexin sands’; base of NP 14; basal Lutetian.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	description	DIMENSIONS. — Diameter = 15 to 16 µm (holotype: d = 16 µm). DISTRIBUTION. — Trochoaster nodosus n. sp. has been identified in many outcrop and borehole sections in the Belgian Basin and the Paris Basin. At the Mont-des-Récollets it has been recorded at the base of Unit A 4 in the upper part of the Aalter Sand Formation. It has been found in the same position (Unit A 4) in the Oedelem BH and the Vlakte van de Raan BH. It has been encountered in the Vilvoorde BH at the base of the Brussel Sand Formation (Unit BA) and is present throughout the ‘ Chaumont-en-Vexin sands‘ at Chaumont-en-Vexin. The LO of T. nodosus n. sp. is also part of the famous calcareous nannofossil turnover, marking the base of NP 14 and the base of the historical Lutetian stratotype. DESCRIPTION This Trochoaster species is characterised by six symmetrically positioned protruding rays with strong median ridges along the rays. The ridges are connected with a central circular ring, which surrounds a triradiate central bridge. The entire body, also the areas between the centrally positioned ridges of the arms, is covered with numerous bumps. These flat interray areas show no furher ornamentation. Specimens of this taxon do not exhibit birefringence under crossed nicols.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC3FEE3FD2FDA93B82B.taxon	discussion	DISCUSSION This taxon differs from all known Trochoaster taxa by its rugged and knobby outline and the configuration of the central ring, where the median ridges along the rays meet. It presents a vague resemblance with T. martinii from the Early Miocene of Germany because of the presence of six protruding rays. The latter is less knobby and presents some fundamental differences in configuration of the central structure and the interray areas.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	description	(Fig. 20 T-W) urn: lsid: zoobank. org: act: 1 A 5 F 4964 - D 75 A- 4631 - A 0 A 4 - E 948 EF 2 E 29 FF	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	materials_examined	HOLOTYPE. — Fig. 20 U (IRSNB b 7161) (negative stored in the collections of the RBINS). PARATYPES. — Three figured specimens from the upper part of the Oedelem Sand Member (top of the Aalter Formation) in the Oedelem BH (Fig. 20 T, V) (IRSNB b 7160, IRSNB b 7162) and the Vlakte van de Raan BH (Fig. 20 W) (IRSNB b 7163); all from the lower part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	diagnosis	DIAGNOSIS. — Three irregularly bifurcated arms interconnected with a fourth arm to form a pyramidal construction surrounded by a weblike structure.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	etymology	DERIVATIO NOMINIS. — Refers to the outline of the solid inner structure of these globular bodies, representing a triangular pyramid.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Brussel Sand Formation, base of Unit B 3; (sample 122.16 - 122.21 m), lower middle part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	description	DIMENSIONS. — Diameter = 10 to 13 µm (holotype: d = 12 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	distribution	DISTRIBUTION. — Trochastrites pyramidalis n. sp. is restricted to the lower part of the Brussel Sand Formation at the Mont-des- Récollets, with rare records in Unit B 1 and Unit B 3 (lower NP 14). It is also known from Unit BE in the Leuven BH (base of NP 14) and from the Aalter-Oedelem area and the offshore Vlakte van de Raan borehole, where it has been identified in the upper part of the Aalter Sand Formation (Unit A 4, base of NP 14). In this offshore borehole it seems to range up to the base of Unit B 4 (sample 79.15 m, Steurbaut unpublished).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	description	DESCRIPTION These nannoliths present a pyramidal structure consisting of three irregularly bifurcated arms lying in a plane and interconnected with a fourth arm almost perpendicular to that plane (Fig. 20 U). This structure is surrounded by a weblike network. The bifurcated part of the arms is quite large compared to the total length of the arms.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A37FFC2FC1FFA86DE90BE43.taxon	discussion	DISCUSSION This taxon differs from Trochastrites hohnensis (Fig. 20 S) by its pyramidal outline and the greater length of the bifurcated parts of the arms. In T. bramlettei (Martini, 1958) the bifurcation of the arms starts much earlier, not far from the central point where the arms meet.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FC75FC1BDBC3BE87.taxon	description	urn: lsid: zoobank. org: act: B 15 DB 477 - B 681 - 4595 - B 2 E 5 - 0 A 0 BCEAC 6 AA 1	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FC75FC1BDBC3BE87.taxon	type_taxon	TYPE SPECIES. — Discolithus spinosus Deflandre & Fert, 1954 by subsequent designation of Hay & Towe (1962).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FF3AFB1FDD16BF4B.taxon	type_taxon	TYPE SPECIES. — Coccolithus foveolatus Reinhardt, 1966 by subsequent designation of Perch-Nielsen (1971).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FC7DFF2DDA9BB944.taxon	description	(Fig. 19 K-N)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FC7DFF2DDA9BB944.taxon	distribution	DISTRIBUTION. — This species is known from several boreholes (e. g. Knokke, Vlakte van de Raan) and outcrops (e. g. Gobertange, Nederokkerzeel, Vossem) in Belgium, where it ranges from the middle of the Brussel Sand Formation (middle part of Unit B 3) up to the basal part of the overlying Lede Sand Formation. In Belgium its range seems to extend from lower middle NP 14 to the base of NP 15. Some rare small-sized specimens have been identified in the ‘ Chaumont-en-Vexin sands‘ and the ‘ Glauconie Grossière s. s. ’ of the Paris Basin (base NP 14). Occurrences outside Europe are scarce and up to now restricted to the Aktulagay section in Kazakhstan (a few specimens in uppermost NP 13, Steurbaut 2011).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FC7DFF2DDA9BB944.taxon	discussion	DISCUSSION This taxon is represented by relatively small forms (d = c. 5 µm) in the early part of its range (e. g. middle of Unit B 3 at Vossem; Fig. 19 M, N). Late forms from the upper part of the Brussel Sand Formation reach up to 8 µm in length (Fig. 19 K).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFC2FF24F886DE1DBDF4.taxon	type_taxon	TYPE SPECIES. — Toweius craticulus Hay & Mohler, 1967 by original designation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	description	(Fig. 18 S-V) urn: lsid: zoobank. org: act: 9 B 705 E 57 - 195 D- 405 F-A 8 C 0 - 51 A 169 BE 9 B 57	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	materials_examined	HOLOTYPE. — Fig. 18 V (IRSNB b 7114) (negative stored in the collections of the RBINS). PARATYPES. — 3 figured specimens (l = 7.2 - 8.8 µm, w = 1.0 µm) from the Brussel Sand Formation, 1 from the Mont-des-Récollets (Unit B 1) (Fig. 18 S) (IRSNB b 7111) and 2 from Vossem (Unit B 3) (Fig. 18 T-U) (IRSNB b 7112, b 7113).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	diagnosis	DIAGNOSIS. — Tiny rhabdoliths, without a basal enlargement or collar, including a tapering stem wirh irregular surface surmounting a thin basal plate.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	etymology	DERIVATIO NOMINIS. — Refers to the thin and delicate rhabdoliths, which are minuscule compared to most of the other representatives of the genus.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	materials_examined	LOCUS TYPICUS. — Vossem: otolith sample taken in middle of the quarry by D. Nolf in 1974, about 1.50 m beneath a conspicuous sandstone (map 32 / 1, x = 164.175, y = 169.290; 50 ° 50 ’ 01.96 ” N, 4 ° 34 ’ 08.96 ” E). STRATUM TYPICUM. — Brussel Sand Formation, middle of Unit B 3; lower middle part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	description	DIMENSIONS. — Length = 7.5 to 10.4 µm; Maximum width of stem = 1.0 to 1.1 µm; Maximum width of basal plate = 1.7 to 2.1 µm (holotype: l = 8.6 µm, wm = 1.1 µm, wbp = 1.8 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	distribution	DISTRIBUTION. — At the Mont-des-Récollets B. minusculus n. sp. ranges from the top of the Aalter Formation (upper part of Unit A 4) up to the upper part of the Brussel Sand Formation (top Unit B 3), although inconsistently and in low numbers. It has not been recorded in Unit B 4, and rarely in the overlying Lede Sand Formation at this locality. It occurs in many outcrops of the Brussel Sand Formation in its type-area (Vossem, Neerijse, St-Lambrechts-Woluwe, Nederokkerzeel, etc.), essentially in Unit B 3 and is known from Unit B 4 in the Vlakte van de Raan BH (Steurbaut unpublished). This species is consistenly present in the ‘ Chaumont-en-Vexin sands’ of the Paris Basin, attributable to the base of NP 14. Hence, its range in the North Sea Basin seems to be restricted to NP 14 and the lower part of NP 15, with a major influx in the lower middle part of NP 14 (Unit B 3). B. minusculus n. sp. has been encountered in west Kazakhstan, also in low numbers, but appearing at a slightly lower position (middle of NP 13) (King et al. 2013).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	description	DESCRIPTION The rhabdoliths of this new taxon are tiny, ranging from 7.5 to 10.4 µm in length. They consist of a slender tapering stem, without a collar, surmounting a thin basal plate. The stem is slightly inflated in its upper part, reaching its maximum thickness at about 1 / 5 of its length, measured from the rounded distal tip. Its surface is rugose. The basal plate consists of 1 layer of radially oriented elements.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A36FFCCFC06FB18DEABBFEF.taxon	discussion	DISCUSSION The presence of an elongated stem, rising vertically from a rather small and thin basal plate, and its optical characteristics (typical vertical extinction line and interference colours of the stem) allow this taxon to be attributed to the genus Blackites. It is distinct from all other described Blackites taxa by its tiny rhabdoliths (generally around 8.5 µm in length, maximum width c. 1 µm). Its silhouette resembles that of B. perlongus, although the latter is twice as long (17 - 18 µm for holotype, see Deflandre & Fert 1954: pl. XII, figs 34 - 35, text fig. 86) and has its maximum thickness in a more central position (c. at the middle of the stem) (see also Bown 2005: pl. 24).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	description	(Fig. 20 A-G) urn: lsid: zoobank. org: act: 1 B 1 CD 3 C 8 - D 67 B- 4 DF 3 - B 110 - 1 F 390 FBA 6203	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	materials_examined	HOLOTYPE. — Fig. 20 A (IRSNB b 7141) (negatives stored in the collections of the RBINS). PARATYPES. — 6 figured specimens from the Brussel Sand Formation, 3 from he Mont-des-Récollets (lower part of Unit B 3) (Fig. 20 B, C, E) (IRSNB b 7142, b 7143, b 7145), 1 from Zaventem, sample 17 (middle part of Unit B 3) (Fig. 20 D) (IRSNB b 7144) and 2 from Vossem, otolith sample Nolf 1974 (Fig. 20 F, G) (IRSNB b 7146, b 7147).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	diagnosis	DIAGNOSIS. — Slightly and somewhat asymmetrically inflated robust rhabdoliths, with faintly rugose surface but without a basal enlargement or collar, of which the maximum width of the stem is much less than the width of the more or less complexly structured basal plate.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	etymology	DERIVATIO NOMINIS. — Refers to the outline of these rhabdoliths, which is inflated, although only slightly and asymmetrically compared to that of B. inflatus, to which it bears a certain resemblance.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Brussel Sand Formation, lower part of Unit B 3 (122.26 - 122.21 m); lower middle part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	description	DIMENSIONS. — Length = 22 to 29 µm (top is generally broken off); Maximum width of stem = 2.5 to 3.8 µm; Width of basal plate = 3.3 to 5.0 µm (holotype: l = 23.0 µm, wm = 3.0 µm, wbp = 4.0 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	distribution	DISTRIBUTION. — At the Mont-des-Récollets Blackites praeinflatus n. sp. occurs in very low numbers in the middle and upper part of the Brussel Sand Formation (Units B 2, B 3 and B 4). It seems to recur at the base of the Lede Sand Formation and the base of the Wemmel Sand Member, but this may be due to reworking. This species has been recorded slightly earlier (top of Unit B 1) at Sint-Stevens-Woluwe, and occurs regularly in Units B 2 and B 3 of many outcrop and borehole sections in Belgium (Vossem, Neerijse, Zaventem; Mol borehole, from 336 to 338 m depth). The earliest records are from the upper part of the Aalter Sand Formation (base of Unit A 4) in the Vlakte van de Raan BH (85.55 m) and from the ‘ Chaumont-en-Vexin sands’ at Chaumont-en-Vexin in the Paris Basin, both attributable to the base of NP 14. It is also known from the base of the ‘ Glauconie Grossière s. s. ’ at Prémontré and at the top of the ‘ Glauconie Grossière s. s. ’ at Gisors (Steurbaut unpublished). Thus, its range appears to be restricted to NP 14, if the spotty occurrences in lower NP 15 (base Lede Sand Formation and base Wemmel Sand Member) are considered to be due to reworking.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	description	DESCRIPTION This species is marked by weakly inflated half-long rhabdoliths with slightly rugose surface and which distally gradually taper to a sharp tip (length = 22 to 29 µm, about 6 times greater than the diameter of the base, which is about 3.3 to 5 µm). The stem starts thickening distally, although only slightly and somewhat asymmetrically, at about 1 / 6 of its length (not at the base, where the width is only 80 % of the maximum width), to reach its greatest diameter at about 1 / 3 of its length. The maximum width of the stem (c. 2.8 µm) measures about 14 % of the total length of the rhabdolith, and is always substantially smaller than the diameter of the basal plate. The latter is complexly structured and seems to consist of two cycles of elements (Fig. 20 G), each with alternating different optical behaviour (clearly seen when inserting the gypsum or quartz plate).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A38FFCEFEEAF9CFDD32B8AE.taxon	discussion	DISCUSSION This form is identical to what has been figured and erroneously attributed to Rhabdosphaera inflata by Aubry (1983: pl. 4, figs 18 - 19; 1986: pl. IV, figs 18 - 19). By the distally slightly inflating stem and the rugose surface it bears a vague resemblance to Blackites inflatus. However, the latter is clearly much more inflated, undoubtedly pointing to a different taxon: the maximum width measures about c. 20 to 25 % (mean of 24 %) of the length of the rhabdolith and is equal or larger than the width of the basal plate (Fig. 20 H: l = 17.5 µm, tip is missing; wm = 3.4 µm; wbp = 2.0 µm, incomplete?). Blackites praeinflatus n. sp. differs from B. spinosus by the general outline of the stem, reaching its maximum thickness at about 1 / 3 of its length, while in B. spinosus the stem is widest at its base (see Bown 2005: pl. 24, figs 21 - 25). It differs also from B. scabrosus (see Deflandre & Fert 1954: pl. XII, fig. 30, text-fig. 85) by its more elongated, less compact stem.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFCEFF1FFD0CDDB5BCB0.taxon	distribution	DISTRIBUTION. — Blackites aff. gladius is only known from three records, one in Belgium, one in the Paris Basin and one in the Aquitaine Basin. It rarely co-occurs with Blackites inflatus in the Isnes quarry in SW Belgium, where its presence seems to be restricted to the top of the Brussel Sand Formation. A few specimens have been identified in the Donzacq Marl (upper NP 14) at Saint-Geoursd’Auribat (Aquitaine Basin) (Lin et al. 2017) and in the upper part of the ‘ Glauconie Grossière s. s. ’ at Margival (Paris Basin, sample 3 in Steurbaut 1988), where it also co-occurs with B. inflatus. B. aff. gladius seems to indicate late Biochron NP 14, also known as Biochon NP 14 b (sensu Berggren et al. 1995). It has not been recorded at the Mont-des-Récollets because of major erosion of the top of the Brussel Sand Formation in N France.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFCEFF1FFD0CDDB5BCB0.taxon	discussion	DISCUSSION This medium-sized rhabdolith (c. 11 µm length) is marked by a very wide basal plate (c. 4.8 µm) and a lensiform stem, which maximum width is located in the upper half of the stem. The latter, which presents a basal collar, seems to be thin-walled (Fig. 20 L) and rugose towards the top. These rhabdoliths bear great resemblance with those of B. gladius (Varol 1989: pl. 4, fig. 5; Bown 2005: pl. 21, figs 10 - 14). However, they differ by certain features of the stem, which is relatively longer and more slender in B. aff. gladius, especially in the top part, as well as by the position of its maximum width. The latter is less distal compared to its position in B. gladius.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFCEFF17F8CFDE50BDF4.taxon	description	urn: lsid: zoobank. org: act: 5 EE 32 ED 4 - 8082 - 410 F-A 611 - 83 ED 3 AB 45 B 46	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFCEFF17F8CFDE50BDF4.taxon	type_taxon	TYPE SPECIES. — Sphenolithus radians Deflandre in Grassé, 1952 by original designation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	description	(Fig. 20 N-Q) urn: lsid: zoobank. org: act: 129 C 12 D 5 - F 3 FE- 47 C 6 - 849 A-EE 69215 A 1 E 64	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	materials_examined	HOLOTYPE. — Fig. 20 N (IRSNB b 7154) (negatives stored in the collections of the RBINS). PARATYPES. — 3 figured specimens (h without spines = 3.8 - 4.8 µm): 1 from the Lede Sand Formation, at Balegem (Fig. 20 O) (IRSNB b 7155) and 2 from Mont-des-Récollets: 1 from the Lede Sand Formation (Fig. 20 P) (IRSNB b 7156) and 1 from the Brussel Sand Formation (Unit B 4) (Fig. 20 Q) (IRSNB b 7157).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	diagnosis	DIAGNOSIS. — Small hourglass-shaped sphenoliths, consisting of a conical proximal column, surmounted by a series of blocky distally widening lateral elements, both of almost equal height, supporting four equally spread diverging spines.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	etymology	DERIVATIO NOMINIS. — Refers to the four conspicuous diverging spines which rise from the corners of the sphenolith.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Lede Sand Formation (sample 126.50 m); lower part of NP 15.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	description	DIMENSIONS. — Height = 11.2 to 12.8 µm with spine; Height body, without spine = 5 to 6.5 µm; Maximum width (wmab) = 4.4 - 5.2 µm (holotype: htotal = 11.2 µm, hpp = 2.5 µm, hle = 2.5 µm, hds = 6.2 µm; wpp = 3.4 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	distribution	DISTRIBUTION. — This species has a rather restricted range. It occurs in the top of the Brussel Sand Formation (Unit B 4) and in the Lede Sand Formation at Mont-des-Récollets, and in several outcrops of the Lede Sand Formation (Balegem, Oosterzele) and the base of the overlying Wemmel Sand Member (Oedelem borehole). Its range seems thus to be restricted to the top of NP 14 and lower NP 15.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	description	DESCRIPTION These sphenoliths are very tiny, consisting of a conical proximal column and a series of blocky lateral elements, which seem to widen distally, producing the typical hourglass shape. The latter is also easily observed in cross polarized light (see discussion below). Both the proximal column and the area with the lateral elements are of almost equal height (each c. 2.5 µm). Half long diverging spines (maximum 1.5 times as long as the sphenolith’s body) emerge from each of the four corners.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3AFFC9FC6AFF2DDDBBBB6E.taxon	discussion	DISCUSSION Sphenolithus quadricornutus n. sp. bears a striking resemblance to Sphenolithus quadrispinatus, described from the Late Miocene (Tortonian, NN 10) of the southern Atlantic (Perch-Nielsen 1980), especially in its dimensions and the length and the position of the spines. They essentially differ in general outline, which is cylindrical in S. quadrispinatus, but hourglass-shaped in S. quadricornutus n. sp. This is also clearly observed in cross-polarized light when seen at 0 °. In this position S. quadrispinatus is highly birefringent, consisting of four almost equal rectangular blocks (height is greater than width), separated by extinction lines with cross pattern. S. quadricornutus n. sp. is also strongly birefringent in that position, but presents an x-shaped interference figure, of which the four bright parts are rather rhombic instead of rectangular and separated by extinction lines with cross pattern. Viewed at 45 ° this cross pattern turns into an x-pattern.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	description	(Fig. 18 Z-AA) urn: lsid: zoobank. org: act: C 09 F 103 A-DD 50 - 4227 - AE 6 E- 3 B 228 A 020 AC 9	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	materials_examined	HOLOTYPE. — Fig. 18 AA (IRSNB b 7119) (negatives stored in the collections of the RBINS). PARATYPES. — 1 figured specimen from the upper part of the Aalter Sand Formation (Unit A 4) at Mont-des-Récollets (sample 116.45 - 116.50 m) (Fig. 18 Z) (IRSNB b 7118).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	diagnosis	DIAGNOSIS. — Rather large sphenoliths, consisting of an almost cubical lower portion, including the proximal shield and lateral elements, and a conspicuous apical spine with particular optical characteristics, made up of a solid centre and two diverging sword-like blades, which remained joined together over more than half of their length, before diverging distally and finally ending in a long distal threadlike structure. Both blades diverge at an angle of about 70 °.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	etymology	DERIVATIO NOMINIS. — Named after the Mont-des-Récollets at Cassel (N France), refers to the type locality and unique locality record of this species.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Brussel Sand Formation, base of Unit B 1 (sample 117.46 - 117.51 m); lower part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	description	DIMENSIONS. — Height = 11.2 to 13.6 µm (exceptionally 20 µm, see Fig. 18 Z) with spine; Height body, without spine = 7.4 to 9 µm; Maximum width (wmab) = 4.4 - 5.2 µm (holotype: htotal = 11.4 µm, hpp = 3.0 µm, hab = 4.4 µm, hds = 4 µm, wpp = 3.2 µm, wmab = 4.4 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	distribution	DISTRIBUTION. — This species has a very restricted range, both in time and in space. Up to now it has only been recorded at Montdes-Récollets, and only in the top of the Aalter Sand Formation (upper part of Unit A 4) and the base of the Brussel Sand Formation (Units B 1 and B 2) (lower middle of NP 14).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	description	DESCRIPTION These sphenoliths are robust and rather large, ranging from 11.2 to 14.0 µm in height. Their proximal portion consists of an irregular lattice, almost quadrangular in lateral view (width slightly larger than height), including a basal layer of radial elements (proximal cycle) surmounted by layers of lateral elements (lateral cycle). The apical spine consists of a solid centre and two diverging sword-like blades. These blades remain joined together over more than half of their length, before diverging at an angle of c. 70 °. The top of each blade is tapering and ends in a thin and moderately long distal threadlike structure. These structures, as well as the top of the blades, are fragile and are often abraded or broken off. The outline of these sphenoliths is unique, as well as their optical behaviour. Viewed between crossed nicols at 0 ° (in position parallel to the polarization directions) the entire sphenolith shows maximum birefringence, with a conspicuous extinction cross in the proximal portion and a vertical extinction line in the apical spine, separating the two halves. Maximum birefringence occurs every 90 °. When viewed at 45 ° the extinction lines in the proximal portion have shifted from a cross-pattern into an x-pattern, whereas only the central part of the apical spine remains strongly birefringent and the blades only faintly. At 32 ° from maximum birefringence one of the blades becomes completely extinct (also most of its centre). The other blade fades out at c. 26 ° further clockwise (at c. 58 ° from the initial starting point).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC9FEC6FE4CDBDFBF32.taxon	discussion	DISCUSSION The outline, structure and optical behaviour of the proximal portion of this new Sphenolithus taxon is very similar to that of Sphenolithus radians (Fig. 19 Q). Both differ by the outline of the apical spine, which consist of 2 diverging blades in S. recolletensis n. sp. The outline of the apical spine of the latter presents some similarities with these of S. furcatolithoides and S. perpendicularis (see Shamrock 2010 a: pl. 1), but clearly differs from these by its massive strongly birefringent candle-shaped form, when viewed at 45 °. The angle between the 2 diverging blades of the apical spine (c. 70 °) is intermediate to that of S. furcatolithoides (c. 35 °) (see Bown 2005: pl. 45) and that of S. perpendicularis (c. 96 °) (Fig. 20 R). The latter, which has been discovered in the middle Lutetian offshore W Australia (lower part of Zone NP 15, restricted to Zone CP 13 a) (Shamrock 2010 a, b), has not been identified at the Mont-des-Récollets. However, a single specimen has been encountered in the middle of the Lede Sand Formation at Balegem (Fig. 20 R). This is the first record of S. perpendicularis in the Belgian Basin.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC8FC6FFA89DD63BBAF.taxon	description	(Fig. 19 P)	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC8FC6FFA89DD63BBAF.taxon	distribution	DISTRIBUTION. — The lowest occurrence of typical Sphenolithus spiniger (as defined below) is in the lower part of the Brussel Sand Formation (at Mont-des-Récollets in Unit B 2). It is known from many outcrop and borehole sections of the Brussel Sand Formation and increases in numbers during the Sphenolithus bloom, as recorded in the Diegem and Zaventem outcrop sections (Steurbaut, detailed in forthcoming study). It occurs rarely in the Lede Sand Formation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3DFFC8FC6FFA89DD63BBAF.taxon	discussion	DISCUSSION This sphenolith differs from the other Sphenolithus taxa described herein by its small triangular outline and very distinctive extinction pattern under crossed nicols. Viewed parallel to the polarisation directions it consists of 4 lobes separated by an extinction cross. The 2 proximal lobes are large and oval; the upper 2, which correspond to the lateral elements and spine, are much smaller and triangular. The extinction cross is much broader at its proximal end, so that the separation between the two lower lobes increases in proximal direction. Forms with a similar outline, but with a clearly different extinction pattern, are attributed to Sphenolithus aff. spiniger, known from the upper part of the Aalter Sand Formation and the Brussel Sand Formation. In these foms the lower 2 lobes are also triangular and the extinction cross is not enlarged proximally.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	description	(Fig. 19 D-F) urn: lsid: zoobank. org: act: 86 C 68780 - D 532 - 4 C 0 E- 9 AB 7 - 8 C 5749 A 5 D 19 A	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	materials_examined	HOLOTYPE. — Fig. 19 D (IRSNB b 7123) (negatives stored in the collections of the RBINS). PARATYPES. — 2 figured specimens from the Mont-des-Récollets (lmax = 17.6 µm): 1 from the sample that yielded the holotype (Unit B 4, sample 122.85 m) (Fig. 20 F) (IRSNB b 7125) and 1 from the base of the Lede Sand Formation (123.50 m) (Fig. 20 E) (IRSNB b 7124).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	diagnosis	DIAGNOSIS. — Large, irregular network of calcite laths, joining at the centre in a central protruding x- shaped wedge.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	etymology	DERIVATIO NOMINIS. — The name is a combination of the Christian names Joachim and Celine, introduced to commemorate and celebrate the wedding day of these two lovely persons.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	materials_examined	LOCUS TYPICUS. — Mont-des-Récollets, ‘ Grande Carrière’, N France; 50 ° 48 ’ 02.74 ” N, 2 ° 30 ’ 23.06 ” E. STRATUM TYPICUM. — Brussel Sand Formation, Unit B 4 (sample 122.85 m); upper part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	description	DIMENSIONS. — Height = 16.8 to 17.6 µm; width = 15.6 to 14.6 µm (holotype: h = 16.8 µm, w = 15.2 µm).	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	distribution	DISTRIBUTION. — At the Mont-des-Récollects this species is consistently present from the upper part of the Brussel Sand Formation (Unit B 4), and ranges through the Lede Sand Formation up to the base of the Wemmel Sand Member (upper NP 14 to lower NP 15). However, there are earlier records from the Oedelem borehole (13.50 m depth, middle of Oedelem Sand Member), assignable to the extreme top of NP 13, and from the Mont-des-Récollets (Unit B 2) and the Nederokkerzeel and Vossem outcrops (upper Unit B 3 of the Brussel Sand Formation), all assignable to the lower middle part of NP 14.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	description	DESCRIPTION This taxon is composed of an irregular complex network of several long calcite laths (up to 7), meeting at different angles in the centre of a more or less cubic structure. The dimensions are highly variable, as the different laths are often broken off. The longest diagonal reaches up to 17.6 µm, the second is generally slightly shorter. The centre is marked by an x-shaped protruding wedge. All calcite laths are strongly birefringent in cross-polarized light.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FEF0FCCFDB18BE71.taxon	discussion	DISCUSSION Similar lathlike networks with central X-shaped to diamond-shaped wedges were described from upper Ypresian deposits of the southern North Sea Basin (Steurbaut 2011). Nannoturba joceliniae n. sp. differs from all previously described Nannoturba species (N. robusta, N. spinosa and N. jolotteana) by a reduced number (up to 7) of long, almost completely free, irregularly distributed laths, which only meet at the centre in an x-shaped to diamond-shaped wedge. In all others taxa the laths are joined over most of their length with different configurations, according to the species (N. robusta with quadrangular disposition and laths meeting at 90 °; N. spinosa with triangular disposition with laths meeting at 120 °; N. jolotteana (Fig. 19 A) resembling a flattened octahedron, with rhombic cross-section). It differs from specimens described as Nannotetrina nitida by Aubry (1983: pl. 5, figs 13 - 14), as well as from the latter’s holotype (originally described as Tetralithus nitidus by Martini 1961: pl. 1, fig. 5, pl. 4, fig. 41), by its large number of different sized laths. In fact, the specimens figured by Aubry also seem to belong to the genus Nannoturba, but probably represent another new species, different from Tetralithus nitidus Martini, 1961.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FECEFDCCDFC3B8F3.taxon	description	urn: lsid: zoobank. org: act: 0 CDB 0 D 30 - 8848 - 48 BC- 8849 - 89 A 35 A 3820 F 0	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
1D2F9F2B9A3CFFC8FECEFDCCDFC3B8F3.taxon	type_taxon	TYPE SPECIES. — Nannoturba robusta Müller, 1979 by original designation.	en	Steurbaut, Etienne, Nolf, Dirk (2021): The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base- Lutetian GSSP. Geodiversitas 43 (11): 311-363, DOI: 10.5252/geodiversitas2021v43a11
