title: A small short-necked hupehsuchian from the lower Triassic of Hubei Province, China.
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.
authors.affiliation: Wuhan Centre of China Geological Survey, Wuhan, Hubei 430023, P. R. China.
authors.forename: Xiao-hong
authors.initials: XH
authors.lastname: Chen
authors.affiliation: Department of Earth and Planetary Sciences, University of California Davis, Davis, California 95616, United States of America.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Motani
authors.affiliation: Wuhan Centre of China Geological Survey, Wuhan, Hubei 430023, P. R. China.
authors.forename: Long
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Laboratory of Orogenic Belt and Crustal Evolution, MOE, Department of Geology and Geological Museum, Peking University, Yiheyuan Str. 5, Beijing 100871, P.R. China.
authors.forename: Da-yong
authors.initials: DY
authors.lastname: Jiang
authors.affiliation: Center of Integrative Research, The Field Museum, Chicago, Illinois 60605-2496, United States of America.
authors.forename: Olivier
authors.initials: O
authors.lastname: Rieppel
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D049628:Body Size; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000502:physiology; D002681:China; D005580:Fossils; D010802:Phylogeny; D012104:Reptiles / Q000033:anatomy & histology* / Q000145:classification* / Q000502:physiology; D012886:Skull / Q000033:anatomy & histology* / Q000502:physiology