Extinct Houndshark
Pachygaleus lefevrei (DAIMERIES, 1891)
aka Galeorhinus lefevrei

Age - Eocene Commonality Common(?)

Tope shark
Galeorhinus ypresiensis (CASIER 1946)

Age - Eocene - Commonality Common(?)

The teeth of Pachygaleus lefevrei and Galeorhinus ypresiensis are very similar. In fact both species had been ascribed to the same genus (Galeorhinus) prior to Cappetta (1992) erecting the new genus Pachygaleus. These teeth have a crown with a distally directed main cusp and multiple cusplets on the distal margin, the crown overhangs the root. The two species can be differentiated by the number of serrations with P. lefevrei having about six serrations and G. ypresiensis only four or five (Kent, 1994). These teeth are small and require the use of a fine mesh screen when collecting.
 

Pachygaleus lefevrei
Monmouth County, NJ.
 

A distinguishing characteristic of both Pachygaleus lefevrei and
Galeorhinus ypresiensis is the crown overhanging the root.
 

Galeorhinus ypresiensis
Monmouth County, NJ.

References
Cappetta H. 1992. Carcharhiniformes nouveaux (Chondrichthyes, Neoselachii) de l’Yprésien du Bassin de Paris. Geobios 25: 639-646
Kent, B. 1994. Fossil Sharks of the Chesapeake Region. Egan Rees & Boyer, Maryland, 146 pp.

Kent, B. W. 1994. Fossil Sharks of the Chesapeake Bay Region. Egan Rees and Boyer, Inc., Columbia, MD, 146 pp.

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