2003. Journal of Vertebrate Paleontology, Abstracts of Papers, 23(3):37.

A NEW SLENDER-SNOUTED CROCODYLIFORM FROM THE UPPER CRETACEOUS MAEVARANO FORMATION, MADAGASCAR

BUCKLEY, Gregory A., ETSUC, Roosevelt University, Chicago, IL; BROCHU, Christopher A., Dept. of Geosciences, University of Iowa, Iowa City, IA; GEORGI, Justin A., Dept. of Anatomical Sciences, SUNY, Stonv Brook, NY.

Several crocodyliforms from the Upper Cretaceous Maevarano Formation in the Mahajanga Basin of northwest Madagascar have been described and discussed in the 10 years since work began in the area as part of several joint SUNY Stony Brook/University of Antananarivo expeditions. The crocodyliform fauna is currently known to contain 7 taxa, including the bizarre, pug-nosed Simosuchus and the large, broad-snouted Mahajangasuchus.

We describe and discuss here the anatomy, phylogenetic relationships and biogeographic implications of a taxon that until recently was known only from fragmentary material. This presently unnamed form is best represented by the posterior portion of a skull and a complete mandible found in association with postcranial elements. The skull possesses a long, narrow snout, large antorbital and supratemporal fenestrae and a squamosal that extends far posteriorly as an elongated process.

The postcranial material consists of five anterior dorsal vertebrae, a scapula and a corocoid, two humeri, and assorted rib fragments. The vertebrae are precoelous and are fused with the neural arches. The humeri both exhibit typical sigmoidal curvature and well-developed deltopectoral crests. The scapula is less complete than the coracoid and only a central portion of a gracile blade is preserved, whereas the coracoid has a well-preserved region for articulation with the scapula and a less well-preserved contribution to the glenoid. Like the scapula, the remainder of the coracoid is gracile with little further lateral expansion.

The biogeographic implications, resulting from the analysis of the phylogenetic relationship of this taxon to other crocodyliforms, are considered along with previously proposed hypotheses using other Malagasy vertebrates.