Uruguaysuchus, RUSCONI, 1933

Soto, Matías, Pol, Diego & Perea, Daniel, 2011, A new specimen of Uruguaysuchus aznarezi (Crocodyliformes: Notosuchia) from the middle Cretaceous of Uruguay and its phylogenetic relationships, Zoological Journal of the Linnean Society 163 (5), pp. 644-645 : 644-645

URUGUAYSUCHUS RUSCONI, 1933

Type species: Uruguaysuchus aznarezi Rusconi, 1933 .

Revised diagnosis: Uruguaysuchus can be diagnosed by the presence of the following unique combination of characters (autapomorphies marked with an asterisk): heterodont dentition (maxilla: 1–2 incisiviform teeth, 1 caniniform tooth and 9–10 post-caniniform teeth; dentary: 6–7 incisiviform teeth, 10–11 ‘postcaniniform’ teeth); hypertrophied 2nd or (in juveniles) 3rd maxillary tooth; post-caniniform spatulated teeth showing strong buccolingual compression, subcircular in shape (in buccal or lingual view), with a pointed central cusp and minute denticles in a single row along the mesial and distal margins*; strong constriction at the base of the crown and marked apicobasal groove along the lingual surface of the root; choanal septum completely divides the opening; posterior region of septum with subcircular cross-section and anterior region T-shaped in cross-section* (broad expansion at the ventral surface of the choana); ventral surface of choanal septum bearing a longitudinal groove; acute anterior tip of the choanal septum that wedges between the palatines; basisphenoid and basioccipital not exposed in ventral view of the skull (given that the extensive posterior region of the pterygoid flanges projects caudally)*; pterygoids fused posterior to the choanal opening, but towards the posterior ends the two flanges meet, forming a narrow sulcus*; posterior border of the choanal opening formed by an elevated rim that projects more ventrally than the palatal surface of the pterygoid flanges*; lateral surface of the quadrate pierced by a dorsally located preotic siphoneal opening, partially exceeding the dorsal margin of the otic aperture*.