Brachycarcharias lerichei (Lamna lerichei), Palaeocene

Order LAMNIFORMES Berg 1958
Family CARCHARIIDAE Müller & Henle 1838
Genus BRACHYCARCHARIAS Cappetta & Nolf 2005
Brachycarcharias lerichei (Casier, 1946) - Lamna lerichei

_____________________________________________________________________________________________________

_____________________________
CASIER, E., 1946. La faune ichthyologique de l'Yprésien de la Belgique. Mémoire du Musée royal d'Histoire naturelle de Belgique, 104: 1-267.

CAPPETTA, H. & NOLF, D., 2005. Révision de quelques Odontaspididae (Neoselachii: Lamniformes) du Paléocène et de l'Eocène du Bassin de la mer du Nord. (Revision of some Odontaspididae (Neoselachii: Lamniformes) from the Palaeocene and Eocene of the North Sea Basin). Bulletin de l'institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre/Aardwetenschappen, 75: 237-266.

CUNNINGHAM, S., 2000. A comparison of isolated teeth of early Eocene Striatolamia macrota (Chondrichthyes, Lamniformes), with those of a recent sand shark, Carcharias taurus. Tertiary Research, 20(1-4): 17-31.

VAN DEN EECKHAUT, G. & DE SCHUTTER, P., 2009. The Elasmobranch Fauna of the Lede Sand Formation at Oosterzele (Lutetian, Middle Eocene of Belgium). Palaeofocus, 1: 1-57, 2 figures, 2 tables, 22 plates.

On elasmo.com: A Review of and Comments on Cappetta & Nolf 2005
Bourdon, Cunningham & De Schutter © 2006

It's obvious that the species lerichei differs from both Carcharias and Odontaspis. Resembling Carcharias the most, they can be distinguished by having anterior teeth with a shorter, non sigmoid crown and a less important root with more isolated lobes (Cappetta & Nolf, 2005). The lingual crown face can have weak striations.

Jim Bourdon used the Cunningham (2000) horizontal dentition methodology to reconstruct a Brachycarcharias lerichei tooth set.

Teeth of this species were classically attributed to Lamna vincenti (Winkler), until Casier's revision in 1946 (Lamna lerichei). Cappetta & Nolf (2005) finally established a new genus (Brachycarcharias) for these teeth.

This species is abundantly present in the early (Casier, 1946) and middle Eocene of Belgium (Leriche, 1905); in the late Thanetian of Belgium and France (Smith et al, 1999); but only very rarely in middle Thanetian deposits (pers obs).