Pararhincodon groessenssi Herman, 1982

Adolfssen, Jan S. & Ward, David J., 2015, Neoselachians from the Danian (early Paleocene) of Denmark, Acta Palaeontologica Polonica 60 (2), pp. 313-338 : 324-325

publication ID	https://doi.org/10.4202/app.2012.0123
persistent identifier	https://treatment.plazi.org/id/C45E8796-6976-197E-FFDB-3E7BFECAB3B7
treatment provided by	Felipe (2024-08-08 23:34:47, last updated 2024-08-09 01:49:55)
scientific name	Pararhincodon groessenssi Herman, 1982
status

Treatment

Fig. 4F–H View Fig .

1982 Pararhincodon groessenssi sp. nov.; Herman, 1982: 143, pl. 2: 9, pl. 4: 2, 3.

Material.—12 teeth from the Ce in Stevns Kridtbrud ( MGUH 29844, MGUH 29845, MGUH 29846, GMV 2012-67).

Description.—Dentition with monognathic heterodonty. Very small teeth with a prominent elongated main cusp, which is slightly inclined towards the commissure in anterior teeth, whereas it is strongly so in lateral teeth. The crown is small and convex with a pair of small shoulders. The shoulders carry short strong folds, whereas the cusp and remaining crown is smooth. The lingual face of the crown is very convex and smooth. The root is slightly asymmetric in anterior teeth, but is much more so in lateral teeth. The root is bilobed, with the mesial lobe in general being longer than the distal, except in anterior teeth. The basal face is flat and the lingual face of the root is high. The lingual face bears a protuberance with central foramina. Foraminae are present lingually below the crown-root junction in each of the shoulders. Anterior teeth appear fairly symmetrical whereas the lateral teeth are strongly asymmetrical. In lateral teeth the distal shoulder carries a small cusplet. Teeth reaching 1.0 mm in height and 0.5 mm in width.

Remarks.—These teeth can be separated from the Cretaceous P. crochardi (Herman, 1977) and P. lehmani ( Cappetta, 1980) and the Ypresian species P. ypresiensis ( Cappetta, 1976) and P. germaini (Adnet, 2006) by being ornamented. All other species of Pararhincodon possess smooth teeth. The difference probably does not allow separation at the generic level. The species P. bilizi described by Reinecke and Engelhard (1997) is very similar to Microscyliorhinus leggetti ( Case, 1994) and may be conspecific with the latter.

Stratigraphic and geographic range.—Campanian and Maastrichtian (Late Cretaceous) of North Germany ( Herman 1982) to the Danian (early Paleocene) of Denmark and possibly also the Campanian (Late Cretaceous) of Texas ( Welton and Farish 1993).

References

Cappetta, H. 1976. Selaciens nouveaux du London Clay de l'Essex (Ypresien du bassin de Londres). Geobios 9: 551 - 575.

Cappetta, H. 1980. Les selaciens du Cretace superieur du Liban. I: Requins. Palaeontographica, Abteilung A 168: 69 - 148.

Case, G. R. 1994. Fossil fish remains from the Late Paleocene Tuscahoma and Early Eocene Bashi Formations of Meridian, Lauderdale County, Mississippi, Part I. Selachians. Palaeontographica, Abteilung A 230: 97 - 138.

Herman, J. 1982. Die Selachier-Zahne aus der Maastricht-Stufe von Hemmoor, Niederelbe (NW-Deutschland). Geologisches Jahrbuch A 61: 129 - 159.

Reinecke, T. and Engelhard, P. 1997. The selachian fauna from Geschiebe of the Lower Selandian basal conglomerate (Thanetian, Late Paleocene) in the Danish subbasin (Sealand, Scania, Western Baltic Sea). Erratica 2: 3 - 45.

Welton, B. J. and Farish, R. F. 1993. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. 204 pp. Before Time, Lewisville.

Figures

Fig. 4. Orectolobiformes from the Danian of Stevns Kridtbrud, Kulstirenden, and Faxe kalkbrud.A–E. Hemiscyllium hermani Müller, 1989. A. MGUH 29839 Ce) anterior tooth in labial (A1), lingual (A2), and lateral (A3) views. B. MGUH 29841 (Br1) anterior tooth in labial (B1) and lingual (B2) views. C. MGUH 29840 (Ce) lateral tooth in labial (C1), lingual (C2), and lateral (C3) views. D. MGUH 29842 (Br1) lateral tooth in labial (D1) and lingual (D2) views. E. MGUH 29843 (Br1) posterior tooth in labial (E1) and lingual (E2) views. F–H. Pararhincodon groessenssi Herman, 1982. F. MGUH 29844 (Ce) anterior tooth in labial (F1) and lingual (F2) views.G. MGUH 29845 Ce) anterior tooth in labial (G1) and lingual (G2) views. H. MGUH 29846 (Ce) lateral tooth in labial view H1) and lingual (H2) views. I. Pararhincodon sp., MGUH 29847 (Br1) anterior tooth in labial (I1) and lingual (I2) views. Scale bars 0.5 mm.