Centroscymnus praecursor Müller and Schöllmann, 1989

Adolfssen, Jan S. & Ward, David J., 2015, Neoselachians from the Danian (early Paleocene) of Denmark, Acta Palaeontologica Polonica 60 (2), pp. 313-338 : 322

Centroscymnus praecursor Müller and Schöllmann, 1989

Fig. 3G, H .

1989 Centroscymnus praecursor sp. nov.; Müller and Schöllmann 1989: 15, pl. 2: 2–8, pl. 5, figs. 6–8.

1993 Centroscymnus praecursor Müller and Schöllmann ; Thies and Müller 1993: 100, figs. 16, 17.

2010 Centroscymnus praecursor Müller and Schöllmann ; Hübner and Müller 2010: 440, fig. 3f–k.

Material.—Two lower teeth and five fragments from the Ce of Stevns Kridtbrud ( MGUH 29834, MGUH 29835, GMV 2012-63 [batch number]).

Description.—Teeth with moderate monognathic heterodonty and strongly dignathic heterodonty. Labio-lingually strongly compressed teeth in general rectangular and approximately twice as high as wide.The cusp is strongly inclined toward the commissure, with an irregular mesial cutting edge. The distal heel is short and convex joining the main cusp in a notch. The labial face of the crown is flat with a large flat apron. The lingual face of the crown is low and smooth. The labial face of the root is low with two pairs of marginal foramina on each side of the apron. The basal edge of the root is almost straight, and divided by a median notch. The basal face of the root is large, covering almost half of the entire tooth, and divided by the median lingual duct, which is connected to the median lingual foramen. The lingual face of the root is limited to the transverse bulge with the central foramen and a mesio-lingual foramen. The labial interlocking hollow is deep in the crown and decreases along the mesial face of the tooth, reaching almost the basal edge of the root. The lingual interlocking hollow is apically limited by the distal heel and reaches basally almost down to the basal edge of the root. Teeth reaching 2 mm in height and 1 mm in width.

Remarks.—Teeth of Centroscymnus praecursor are known from the Campanian of north-west Germany ( Herman 1982; Müller and Schöllmann 1989). Whether the squaloids already were deep-water species in the early Late Cretaceous as stated by Klug and Kriwet (2010) is debated: although most living squaloids are deep-water, not all are ( Compagno et al. 2005), nor are all the locations of fossil squaloids from deep-water facies ( Siverson 1993b).

Stratigraphic and geographic range.—Campanian (Late Cretaceous) of North-West Germany ( Herman 1982; Müller and Schöllmann 1989; Hübner and Müller 2010) to the Danian (early Paleocene) of Denmark.

Figures

Fig. 3. Hexanchiformes, Squaliformes, and Squatiniformes from the Danian of Stevns Kridtbrud, Kulstirenden, and Faxe kalkbrud. A. Chlamydoselachus sp., MGUH 29828, DK635 (Ce) lateral tooth in labial (A 1), lingual (A 2), and distal (A 3) views. B–E. Squalus gabrielsoni Siverson, 1993. B. MGUH 29829 (Ce) lower anterior tooth in labial (B 1) and lingual (B 2) views. C. MGUH 29830 (Ce) lower lateral tooth in labial (C 1) and lingual (C 2) views. D. MGUH 29831 (Br1) lateral tooth in labial (D 1) and lingual (D 2) views. E. MGUH 29832 (Br1) lateral tooth in labial (E 1) and lingual (E 2) views. F. Squaliodalatias sp., MGUH 29833 (Ce) lateral tooth in labial view (F 1), lingual (F 2), and distal (F 3) views. G, H. Centroscymnus praecursor Müller and Schöllmann, 1989. G. MGUH 29834 (Ce) lower tooth in labial (G 1) and lingual (G 2) views. H. MGUH 29835 (Ce) lower tooth in labial (H 1) and lingual (H 2) views. I, J. Squatina sp. I. MGUH 29836 (Ce) lateral tooth in labial (I 1) and lingual (I 2) views. J. MGUH 29837 (Ce) lateral tooth in labial (J 1) and lingual (J 2) views. K. Parasquatina cappettai Herman, 1982, MGUH 29838 (Ce) tooth in labial view (K ), lingual (K ), and distal (K ) views.