Monday, June 22, 2009

New skeletal drawing: Acrophoca longirostris

Hey all,

Here's a new drawing I was able to complete on one of my days off between Geology Field Camp projects. It's a skeletal drawing of Acrophoca longirostris, a very strange pinniped from the early Pliocene Pisco Formation of Peru (as well as from Chile; Walsh and Naish 2002). Acrophoca is a Monachine true seal (family Phocidae), and as stated above, is known from the early Pliocene of the Southeast Pacific. According to the phylogeny of Demere et al. 2003, Acrophoca is the sister taxon of the fearsome Leopard seal, Hydrurga leptonyx. Acrophoca was originally named by Muizon (1981). The skeleton I drew this from can be seen on display at the USNM. Ordinarily I'd give more information, but I need to pack up for my road trip.

Demere, T.A., A. Berta and P.J. Adam. 2003. Pinnipedimorph evolutionary biogeography. Bulletin of the American Museum of Natural History 13:32-76.

C. Muizon. 1981. Les vertebres fossiles de la Formation Pisco (Perou). Premiere parti: Deux nouveaux Monachina (Phocidae, Mammalia) du Pliocene de Sud-Sacaco. Recherche sur les grandes civilisations Memoire 6:1-150

Walsh, S. A. & Naish, D. 2002. Fossil seals from late Neogene deposits in South America: a new pinniped (Carnivora, Mammalia) assemblage from Chile. Palaeontology 45: 821-842.


Darren Naish said...

Awesome! Any word yet on the additional species that are (apparently) soon to be described? At least one is even longer-skulled than longirostris.

Sordes said...

Really a nice drawing! I was thinking about sculpting Acrophoca, but there are only very few picture sources. When I saw a skull of Acrophoca longirostris from Peru at the NHM Karlsruhe I was really impressed how incredibly long and narrow the skull is. Really a weird beast.