The world's largest gharials Gryposuchus: Description of G. croizati n. sp. (Crocodylia, Gavialidae) from the Upper Miocene Urumaco Formation, Venezuela

Abstract

A new fossil gharial Gryposuchus species is described from the Upper Miocene Urumaco Formation, Venezuela. Gryposuchus croizati new species can be distinguished from other gavialoids, including Gryposuchus colombianus and Gryposuchus neogaeus by the following combination of diagnostic characters: 1) slenderness of the parietal interfenestral bar; 2) dental formula, mainly the lesser number of maxillary teeth, with four premaxillary, 19 maxillary and 22 mandibular teeth; 3) large width of palatines between the reduced palatine fenestrae; 4) medial hemicondyle of the quadrate smaller but detached and much more posteriorly elongated than the lateral one and projected ventromedially; 5) pterygoid morphology, with two posterior vacuities. The polymorphism in the contour of the external naris in Gryposuchus was evaluated for taxonomic significance. The body size of G. croizati n. sp. was estimated in 10.15 m (9.67-10.67 m) using the dorsal skull length and the estimation of the body mass was 1,745 kg (1,280-2,379 kg) based on the braincase length. These maximal values place G. croizati n. sp. among the world's largest gharials and even Crocodyliforms as a whole. © 2008 E. Schweizerbart'sche Verlagsbuchhandlung.