A small short-necked hupehsuchian from the lower Triassic of Hubei Province, China

PLoS One. 2014 Dec 17;9(12):e115244. doi: 10.1371/journal.pone.0115244. eCollection 2014.

Abstract

Hupehsuchia is a group of enigmatic Triassic marine reptiles that is known exclusively from two counties in Hubei Province, China. One of the common features of the group was a modestly long neck with nine to ten cervical vertebrae. We report a new species of Hupehsuchia, Eohupehsuchus brevicollis gen. et sp. nov., which for the first time shows a short neck in this group, with six cervicals. The configuration of the skull roof in Eohupehsuchus is also unique among Hupehsuchia, with narrow frontals and posteriorly shifted parietals, warranting recognition of a new species. The taxon superficially resembles Nanchangosaurus in retaining hupehsuchian plesiomorphies, such as low neural spines and small body size. However, its limbs are well-developed, unlike in Nanchangosaurus, although the latter genus is marginally larger in body length. Thus, the individual is unlikely to be immature. Also, Eohupehsuchus shares a suite of synapomorphies with Hupehsuchus, including the second and third layers of dermal ossicles above the dorsal neural spines. A phylogenetic analysis suggests that the new species is not the most basal hupehsuchian despite its short neck, and instead forms the sister taxon of Hupehsuchidae. Until recently, Hupehsuchia contained only two monotypic genera. Now there are at least four genera among Hupehsuchia, and the undescribed diversity is even higher. The left forelimb of the only specimen is incomplete, ending with broken phalanges distally. The breakage could only have occurred pre-burial. The individual may have been attacked by a predator and escaped, given that scavenging is unlikely.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Animals
  • Body Size
  • Cervical Vertebrae / anatomy & histology*
  • Cervical Vertebrae / physiology
  • China
  • Fossils*
  • Phylogeny
  • Reptiles / anatomy & histology*
  • Reptiles / classification*
  • Reptiles / physiology
  • Skull / anatomy & histology*
  • Skull / physiology

Grant support

This work was supported by the China Geological Survey Project 1212010611603 to Xiao-hong Chen, the China Geological Survey Projects 1212011120148 to Long Cheng, and the National Natural Science Foundation of China Projects 40920124002 and 41372016 to Da-yong Jiang. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.