Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China

HENDRICKX, CHRISTOPHE; HAN, FENGLU; WU, XIAO-CHUN; CURRIE, PHILIP J.; CHOINIERE, JONAH N.; STIEGLER, JOSEF; XU, XING

CANADIAN JOURNAL OF EARTH SCIENCES

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Año: 2020 p. 1 - 21

0008-4077

The dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou Formation of China is comprehensively described. We highlight a combination of dental features that appear to be restricted to Sinraptor: i) crowns with denticulated mesial and distal carinae extending from the root, and an irregular surface texture on the enamel; ii) D- to salinon-shaped cross-sectional outline at the crown-base in mesialmost teeth; iii) mesial crowns with mesial carinae spiraling mesiolingually and lingually positioned longitudinal groove adjacent to the mesial carina; and iv) labiolingually compressed lateral teeth with weakly labially deflected distal carinae, flat to concave basocentral surfaces of the labial margins of the crowns, and horizontally elongated distal denticles showing short to well-developed interdenticular sulci. Using cladistic, multivariate, discriminant and cluster analyses, we demonstrate that the dentition of Sinraptor is relatively similar to that of ceratosaurids, megalosauroids and other allosauroids, and particularly close to that of Allosaurus. The dental anatomy of Sinraptor and Allosaurus, which mainly differs in the labiolingual compression of the lateral crowns and the number of premaxillary teeth, shows adaptations towards a predatory lifestyle, including premaxillary teeth capable of enduring bone-to-bone contact, and crowns with widely separated mesial and distal carinae capable of inflicting widely open wounds.