Sunosuchus junggarensis sp.nov. (Archosauria: Crocodyliformes) from the Upper Jurassic of Xinjiang, People's Republic of China

Abstract

A new species of Crocodyliformes, Sunosuchus junggarensis, is established on the basis of six individuals from the Upper Jurassic of the Junggar Basin, Xinjiang, northwest China. It differs from other species of Sunosuchus primarily in having a dorsoventrally depressed supraoccipital that, in occipital view, lacks a median crest; a frontal that is ridged anteriorly; a distinct depression distal to the foramen aëreum on the dorsal surface of the quadrate; and an elongate, undivided maxillary depression. Cranial ontogenetic variation in S. junggarensis is discussed. Sunosuchus is probably a goniopholidid crocodyliform. It is distinguished from other genera of the Goniopholididae by a narrow and elongate snout, a small skull table, a partially ridged frontal, a pair of anteriorly located anterior palatal fenestrae, a lateroventrally–mediodorsally expanded retroarticular process, some enlarged pits on the frontal, and an elongate mandibular symphysis, with the splenial forming a small part of it. Sunosuchus, Eutretauranosuchus, and some species of Goniopholis may form a monophyletic group within the Mesoeucrocodylia.