Pachygaleus lefevrei ( Daimeries, 1891 )

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 : 65-66

Pachygaleus lefevrei ( Daimeries, 1891)

Fig. 23 Q–V

Galaeus lefeveri Daimeries, 1891: 74 .

Eugaleus falconeri White, 1926: 73 .

Galeus lefevrei – Leriche 1905: 136 , pl. 8, figs 54–58.

Eugaleus lefevrei – Casier 1946: 84 , pl. 1, fig. 13a–b.

Galeorhinus lefevrei – Casier 1966: 86 , pl. 8, figs 4–6.

Pachygaleus lefevrei – Baut & Genault 1995: 206 , pl. 7, figs 5–6, pl. 8, figs 1–2.

Material examined

UNITED STATES OF AMERICA – Alabama • 9 isolated teeth; Claiborne Group; MSC 37688, MSC 35758.1–2, MSC 35763, MSC 38289.1–2, MSC 38487, NJSM 24024, WSU 5002.

Description

Teeth mesiodistally wider than tall. Crown labiolingually thick and conspicuously overhangs the root labially. Labial crown face flat to concave; lingual face strongly convex. Main cusp distally directed, formed from intersection of elongate, convex mesial cutting edge and much shorter distal edge. Elongated distal heel often concave, may be flat or slightly sigmoidal on lateral teeth. Distal heel with three-to-10 pronounced cusplets, which are distally directed and decreasing in size away from cusp. Crown enameloid generally smooth, but short longitudinal folds sometimes located at base of labial crown face on extreme lateral teeth or juveniles. Root thick and bulbous, bilobate, with widely diverging and rounded lobes; shallow, U-shaped interlobe area. Wide and deep nutritive groove located on lingual root face; large central foramen occurs within groove. Additional foramina present on basal portion of lingual root face.

Remarks

The genus Pachygaleus currently only contains the species P. lefevrei ( Daimeries, 1891) , and all of our specimens are assigned to this taxon. The Pachygaleus teeth in our sample were separated from those of Galeorhinus by their larger size, more convex labial crown face, wider U-shaped interlobe area and, in the case of the anterolateral teeth, up to 10 cusplets on the distal heel.

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1, the contact of the Tallahatta and Lisbon formations at site ACh-14, and the basal Lisbon Formation at site ACov-11. Upper Ypresian to lower Lutetian, zones NP14 and NP15.

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.