Galeorhinus louisi Adnet & Cappetta, 2008

Ebersole, Jun A., Cicimurri, David J. & Stringer, Gary L., 2019, Taxonomy and biostratigraphy of the elasmobranchs and bony fishes (Chondrichthyes and Osteichthyes) of the lower-to-middle Eocene (Ypresian to Bartonian) Claiborne Group in Alabama, USA, including an analysis of otoliths, European Journal of Taxonomy 585, pp. 1-274 : 63-64

Galeorhinus louisi Adnet & Cappetta, 2008

Fig. 23 G–J

Galeorhinus louisi Adnet & Cappetta, 2008: 438 , fig. 4.

Material examined

UNITED STATES OF AMERICA – Alabama • 2 isolated teeth; Claiborne Group ; MSC 37353.1 – 2 .

Description

Teeth small, not exceeding 2.2 mm in mesiodistal width; distal-most extent of main cusp in line with, or slightly exceeding, distal extent of heel. Mesial cutting edge elongate, ranges from straight to slightly sinuous; distal edge much shorter, slightly convex, forms triangular and distally inclined cusp with mesial edge. Prominent distal heel bears one or two cusplets, which are not well differentiated from the heel itself. Lingual crown face smooth, strongly convex. Labial face with bulbous base that overhangs the root; very short folds and wrinkles at base that coalesce apically to form a transverse ridge (easily seen in profile view). Root high and thick, with highly diverging and rounded lobes; lobes separated by shallow and triangular interlobe area. Lingual root face bisected by deep nutritive groove.

Remarks

The teeth in our sample appear conspecific to the holotype of G. louisi Adnet & Cappetta, 2008 in that they have extensive folds and notches present along the entire width of the labial crown base. This ornamentation is indistinct or absent on the teeth of G. minutissimus , present only beneath the heels on the teeth of G. mesetaensis , and is much less extensive on the teeth of G. duchaussoisi (see above) and G. ypresiensis (see below).

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the Tallahatta Formation at site AMo-8. Lower Lutetian, Zone NP14.

Figures

Fig. 23. Galeorhinus de Blainville, 1816 and Pachygaleus Cappetta, 1992, teeth. A–F. Galeorhinus aff. G. duchaussoisi Adnet & Cappetta, 2008. A–C. MSC 35756.1, lower Tallahatta Formation. A. Labial view. B. Lingual view. C. Mesial view. D–F. MSC 37691, basal Lisbon Formation. D. Labial view. E. Lingual view. F. Mesial view. — G–J. G. louisi Adnet & Cappetta, 2008, MSC 37353.2, lower Tallahatta Formation. G. Labial view. H. Lingual view. I. Mesial view. J. Close–up of labial wrinkling. — K–M. G. aff. G. duchaussoisi, MSC 37353.4, Tallahatta Formation. K. Labial view. L. Lingual view. M. Mesial view. — N–P. Galeorhinus ypresiensis (Casier, 1946), MSC 37693.1, Gosport Sand. N. Labial view. O. Lingual view. P. Mesial view. — Q–V. Pachygaleus lefevrei (Diameries, 1891). Q–S. MSC 37688, basal Lisbon Formation. Q. Labial view. R. Lingual view. S. Mesial view. T–V. MSC 35763, lower Tallahatta Formation. T. Labial view. U. Lingual view. V. Mesial view. Scale bars = 2 mm.