Abstract

HERRERA, Yanina; FERNANDEZ, Marta S  and  VARELA, Julio A. Forelimb Morphology of Geosaurus Araucanensis Gasparini and Dellapé, 1976 (Crocodyliformes: Thalattosuchia). Ameghiniana [online]. 2009, vol.46, n.4, pp.657-667. ISSN 1851-8044.

The Metriorhynchidae has been interpreted as the only clade of archosaurs entirely adapted to pelagic marine life. The cranial morphology of these crocodyliforms is well known, however the number of contributions that include postcranial descriptions is scarce, especially about the appendicular skeleton. To resolve the conflict about the phylogenetic relationships of this group, as well as to test the macroevolutionary patterns is necessary to incorporate information about all regions of the skeleton. In this paper, we describe for the first time the forelimb of Geosaurus araucanensis Gasparini and Dellapé, 1976. The articulated forelimb of one specimen allows recognising one ossified element that belongs to the proximal carpus, which has never been described for Metriorhynchidae. Herein we proposed that this ossified element is the pisiform.

Keywords : Thalattosuchia; Metriorhynchidae; Geosaurus araucanensis; Forelimb; Carpus; Pisiform.