Crioceratites primitivus Reboulet, 1996

Vašíček, Zdeněk, Błażejowski, Błażej, Gaździcki, Andrzej, Król, Maria, Lefeld, Jerzy, Skupien, Petr & Wierzbowski, Andrzej, 2020, Early Cretaceous ammonites and dinoflagellates from the Western Tatra Mountains, Poland, Acta Palaeontologica Polonica 65 (4), pp. 799-810 : 804

Crioceratites primitivus Reboulet, 1996

Fig. 4A–C .

1996 Crioceratites primitivus n. sp.; Reboulet 1996: 175, pl. 24: 1–5,

non pl. 23: 3 (= Crioceratites heterocostatus Mandov, 1976 ). 2007 Crioceratites primitivus Reboulet ; Klein et al. 2007: 44.

Material.—Three large specimens ( ZPAL Am. 25/15, 25/2, and positive G/1728/MT, rock slab with imprint), preserved mainly in form of weathered imprints of the ultimate whorl and as limonitised outer moulds of the flattened part of the penultimate whorl. Flattening results from lateral deformation. The imprint of the ultimate whorl of the ZPAL Am. 25/15 shows attached three calcite valves of small bivalves

Fig. 4C–G ). All from Cretaceous, Tatra Mountains, Poland.

Description.—Distinctly free coiled specimens. Thin and dense ribs occur on a better preserved limonitised positive. Occasionally, some of the ribs seem to be stronger than others. A partially preserved ventrolateral spine with an incomplete length of 8 mm (at the height of the deformed whorl of approximately 20 mm) can be found at the end of the penultimate whorl of the second specimen. Trituberculated main ribs are visible on imprints of the ultimate whorl. Two significant ventrolateral spines reaching the length of approximately 20 mm are preserved on the ZPAL Am. 25/15. The first main rib occurs on the ZPAL Am.25/2 at the diameter D of about 75 mm. Seven thin ribs are inserted between the pair of main ribs.

Measurement.—In theaxisofelongationthe ZPALAm.25/15 reaches maximum diameter of 150 mm. At D = 73.5 mm, H = 19.0 mm (H/D = 0.26) and U = 43.5 mm (U/D = 0.59).

The maximum diameter of the ZPAL Am. 25/ 2 in the axis of elongation is about 200 mm.

Remarks.—Large, imperfectly preserved specimens provide information about the maximum size of shells of Crioceratites primitivus . Strong trituberculated ribs bear significant ventrolateral spines.

Stratigraphic and geographic range.—The Reboulet’s (1996) type material comes from the uppermost Valanginian sediments of the Vocontian Basin in France. The findings from theWesternCarpathians (theButkovQuarry, Slovakia) come from the sediments around the Valanginian–Hauterivian boundary ( Michalík et al. 2013).

Figures

Fig. 4. A–C. The Lower Cretaceous heteromorph ammonite Crioceratites primitivus Reboulet, 1996 from the Kościeliska Marl Formation in the Lejowa Valley, Tatra Mountains, Poland. A. G/1728/MT. B. ZPAL Am. 25/2. C. ZPAL Am. 25/15. D. Distribution of anomiid individuals on a specimen of C. primitivus (ZPAL Am. 25/15). E–G. Close up views of bivalves attached to the body chambers of the ammonite C. primitivus (ZPAL Am. 25/15). All in lateral view.