Journal of Paleontology, 91(6), 2017, p. 1306–1312 Copyright © 2017, The Paleontological Society 0022-3360/17/0088-0906 doi: 10.1017/jpa.2017.12
Taxonomic Note
A new diapsid from the Middle Triassic of southern China Chun Li,1 Nicholas C. Fraser,2 Olivier Rieppel,3 Li-Jun Zhao,4 and Li-Ting Wang5
1Institute of Vertebrate Palaeontology and Palaeoanthropology, Laboratory of Evolutionary Systematics of Vertebrates, P.O. Box 643, Beijing, 100044, People’s Republic of China ⟨
lichun@ivpp.ac.cn⟩ 2National Museums Scotland, Chambers Street, Edinburgh EH1 1JF, UK ⟨
nick.fraser@
nms.ac.uk⟩ 3Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago IL 60605, USA ⟨
orieppel@fieldmusuem.org⟩ 4Zhejiang Museum of Natural History, 71 Jiaogong Road, Hangzhou, Zhejiang 310012, P.R. China 5Geological Survey of Guizhou Province, Guiyang 550005, P.R. China
Abstract.—The Middle and early Late Triassic of southern China is well known for a remarkable diversity of marine vertebrates, particularly reptiles, including an abundance of intriguing new forms (e.g., Jiang et al., 2005; Hu et al., 2011; Li et al., 2016). Here we describe a new diapsid from Yunnan Province. It possesses an elongate neck that exhibits a remarkable similarity to that of many Protorosauria, yet in other respects the skull and postcranium are much less derived. The newtaxon is part of the so-called Panxian-Luoping Fauna and the deposits correspond to the Upper Member of
the Guanling Formation, comprising thin to medium bedded, gray to dark-gray laminated marly limestone and limestone, with several layers of bentonite intercalated in the fossil level at Panxian (Wan, 2002; Motani et al., 2008; Jiang et al., 2009). Their age is Pelsonian (middle Anisian, Middle Triassic) as is indicated by the conodont Nicoraella kockeli Zone (Sun et al., 2006; Zhang et al., 2009). A recent U-Pb study indicates the absolute age of these middle Anisian beds to be close to 244Ma (Wang et al., 2014).
Materials and methods
The description is based on a single, well-preserved, articulated, and almost complete specimen, including the distal-most caudal vertebrae (Fig. 1). It was collected from the Guanling Formation of Luoping County in Yunnan Province. It was prepared by, and is now housed in, the Institute of Vertebrate Palaeontology and Palaeoanthropology in Beijing.
Repository and institutional abbreviation.—IVPP, Institute of Vertebrate Palaeontology and Palaeoanthropology,Beijing,China.
Systematic paleontology Reptilia
Archosauromorpha von Huene, 1946 ?Protorosauria Huxley, 1871 Family incertae sedis
Genus Pectodens new genus
Type species.—Pectodens zhenyuensis n. gen. n. sp. bymonotypy. Diagnosis.—As for type species.
Etymology.—From the Latin pecto meaning to comb and dens meaning teeth; in reference to the comb-like nature of the marginal dentition.
Occurrence.—Luoping County of Yunnan Province, China; Member II of the Guanling Formation, Anisian, Middle Triassic.
Pectodens zhenyuensis new species Holotype.—IVPP V18578. Almost complete articulated skeleton.
Diagnosis.—Small, gracile diapsid (about 38cm long), with long tail and neck, ten premaxillary teeth, numerous elongate conical teeth forming comb-likemarginal dentition, palatal teeth at least on the pterygoid present, temporal region short. At least ten, and probably eleven, or even twelve elongate cervical vertebrae bearing ribs with a short anteriorly projecting process and a long posterior shaft that extend parallel to the neck and bridge at least two intervertebral joints. Dorsals with prominent transverse processes that terminate in subcircular facets for the ribs. Between eleven and thirteen dorsal, two sacral, and 41 caudal vertebrae. The tibia as long, or just slightly longer than, the femur. An elongate metatarsal V that is not hooked.
Occurrence.—Luoping County of Yunnan Province, China; Member II of the Guanling Formation, Anisian, Middle Triassic.
Description.—Positioned on two blocks, the specimen is preserved with the right side of the skull and neck exposed, but
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