The Science of Nature

, 103:95 | Cite as

A new armored archosauriform (Diapsida: Archosauromorpha) from the marine Middle Triassic of China, with implications for the diverse life styles of archosauriforms prior to the diversification of Archosauria

  • Chun LiEmail author
  • Xiao-chun WuEmail author
  • Li-jun Zhao
  • Sterling J. Nesbitt
  • Michelle R. Stocker
  • Li-Ting Wang
Original Paper


Reptiles have a long history of transitioning from terrestrial to semi-aquatic or aquatic environments that stretches back at least 250 million years. Within Archosauria, both living crocodylians and birds have semi-aquatic members. Closer to the root of Archosauria and within the closest relatives of the clade, there is a growing body of evidence that early members of those clades had a semi-aquatic lifestyle. However, the morphological adaptations to a semi-aquatic environment remain equivocal in most cases. Here, we introduce a new Middle Triassic (245–235 Ma) archosauriform, Litorosuchus somnii, gen. et sp. nov., based on a nearly complete skeleton from the Zhuganpo Member (Ladinian [241–235 Ma]) of the Falang Formation, Yunnan, China. Our phylogenetic analyses suggest that Litorosuchus is a stem archosaur closely related to the aberrant Vancleavea just outside of Archosauria. The well-preserved skeleton of L. somnii bears a number of morphological characters consistent with other aquatic-adapted tetrapods including: a dorsally directed external naris, tall neural spines and elongate chevrons in an elongated tail, a short and broad scapula, webbed feet, long cervical vertebrae with long slender ribs, and an elongated rostrum with long and pointed teeth. Together these features represent one of the best-supported cases of a semi-aquatic mode of life for a stem archosaur. Together with Vancleavea campi, the discovery of L. somnii demonstrates a growing body of evidence that there was much more diversity in mode of life outside Archosauria. Furthermore, L. somnii helps interpret other possible character states consistent with a semi-aquatic mode of life for archosauriforms, including archosaurs.


Reptile Morphology Phylogeny Adaptation Semi-aquatic 



We are grateful to J-Z Ding (IVPP) for skillful preparation of the specimen used in this study, W Gao (IVPP) for photographic work, and Y Chen for the first draft of the skeletal reconstruction. X-CW particularly wishes to thank the IVPP and Zhejiang Museum of Natural History, Hangzhou, China (ZMNH) for hospitality during his visits. H-D Sues, S Brusatte, and an anonymous reviewer carefully reviewed the manuscript, offering critical comments and suggestions that led to its great improvement. This work was supported by research grants from the National Natural Science Foundation of China (NNSFC-41172027 and 41472020 to L-JZ and X-CW), from State Key Laboratory of Palaeobiology and Stratigraphy of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (no. 153105 to CL), from Canadian Museum of Nature (RCP09 to X-CW) as well as from generous supports from the IVPP (to CL), from the ZMNH (to L-JZ), and from the Department of Geosciences at Virginia Tech (to SJN and MRS).

Supplementary material

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ESM 1 (DOCX 1972 kb)


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© Her Majesty the Queen in Right of Canada as represented by: Canadian Museum of Nature 2016

Authors and Affiliations

  1. 1.Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijingPeople’s Republic of China
  2. 2.Canadian Museum of NatureOttawaCanada
  3. 3.Zhejiang Museum of Natural HistoryHangzhouChina
  4. 4.Department of GeosciencesVirginia Polytechnic Institute and State UniversityBlacksburgUSA
  5. 5.Geological Survey of Guizhou ProvinceGuiyangChina

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