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New mixosaurid ichthyosaur specimen from the Middle Triassic of SW China: further evidence for the diapsid origin of ichthyosaurs

Published online by Cambridge University Press:  14 July 2015

Jun Liu ,
Jonathan C. Aitchison ,
Yuan-Yuan Sun ,
Qi-Yue Zhang ,
Chang-Yong Zhou  and
Tao Lv
Jun Liu
Affiliation:
1Chengdu Center of China Geological Survey, Chengdu, China 2Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China,
Jonathan C. Aitchison
Affiliation:
2Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China,
Yuan-Yuan Sun
Affiliation:
1Chengdu Center of China Geological Survey, Chengdu, China
Qi-Yue Zhang
Affiliation:
1Chengdu Center of China Geological Survey, Chengdu, China
Chang-Yong Zhou
Affiliation:
1Chengdu Center of China Geological Survey, Chengdu, China
Tao Lv
Affiliation:
1Chengdu Center of China Geological Survey, Chengdu, China
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Abstract

Recent cladistic analyses have all suggested a diapsid origin of ichthyosaurs. However, an intermediate evolutionary stage of the lower temporal region of ichthyosaurian skull between basal diapsids and derived ichthyosaurs has been absent from the fossil record. Here we describe the cranial skeleton of a new mixosaurid ichthyosaur specimen with a well-preserved lower temporal region from the Anisian Guanling Formation of eastern Yunnan. It is characterized by the most primitive lower temporal region within known ichthyosaurs. The primitive characters of the lower temporal region include both external and internal separation between the jugal and the quadratojugal, an anterior process of the quadratojugal, an apparent posteroventral process of the jugal, and a large lower temporal opening surrounded by the jugal, the postorbital, the squamosal, and the quadratojugal. The lower temporal region of this specimen provides the most direct evidence to the diapsid origin of ichthyosaurs. It also suggests that the disappearance of the lower temporal fenestra is caused initially by the reduction of the lower temporal arcade rather than the enlargement of the surrounding bones.

Type
Research Article
Information
Journal of Paleontology , Volume 85 , Issue 1 , January 2011 , pp. 32 - 36
Copyright
Copyright © The Paleontological Society 

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References

Baur, G. 1887. On the morphology and origin of Ichthyopterygia. American Naturalist, 21:837–840.Google Scholar
Caldwell, M. W. 1996. Ichthyosauria: a preliminary phylogenetic analysis of diapsid affinities. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 200:361–386.Google Scholar
Callaway, J. M. 1997. Ichthyosauria: introduction, p. 3–16. In Callaway, J. M. and Nicholls, E. L. (eds.), Ancient marine reptiles. Academic Press, San Diego.Google Scholar
Carroll, R. L. 1985. Evolutionary constraints in aquatic diapsid reptile. Special Papers in Palaeontology, 33:145–155.Google Scholar
Carroll, R. L. 1988. Vertebrate Paleontology and Evolution. W.H. Freeman and Company, New York.Google Scholar
Carroll, R. L. and Dong, Z. M. 1991. Hupehsuchus, an enigmatic aquatic reptile from the Triassic of China, and the problem of establishing relationships. Philosophical Transactions of the Royal Society of London Series B: Biological Sciences, 331:131–153.Google Scholar
de Blainville, H. M. D. 1835. Description de quelques espèces de reptiles de la Californie, précedée de l'analyse système général d'érpetologie et d'amphibiologie. Nouvelles Annales du Muséum d'Histoire Naturelle, Paris, 4:236–296.Google Scholar
Fröbisch, N. B., Sander, P. M., and Rieppel, O. 2006. A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and a re-evaluation of the skull osteology of the genus. Zoological Journal of the Linnean Society, 147:515–538.Google Scholar
Jiang, D. Y., Hao, W. C., Maisch, M. W., Matzke, A. T., and Sun, Y. L. 2005. A basal mixosaurid ichthyosaur from the Middle Triassic of China. Palaeontology, 48:869–882.Google Scholar
Jiang, D. Y., Schmitz, L., Hao, W. C., and Sun, Y. L. 2006. A new mixosaurid ichthyosaur from the Middle Triassic of China. Journal of Vertebrate Paleontology, 26:60–69.Google Scholar
Jiang, D. Y., Schmitz, L., Motani, R., Hao, W. C., and Sun, Y. L. 2007. The mixosaurid ichthyosaur Phalarodon cf. P. fraasi from the Middle Triassic of Guizhou Province, China. Journal of Paleontology, 81:602–605.Google Scholar
Leidy, J. 1868. Notice of some reptilian remains from Nevada. Proceedings of the Philadelphia Academy of Sciences, 20:177–178.Google Scholar
Lhwyd, E. 1699. Eduardi Luidii apud oxonienses cimeliarchae ashmoleani lithophylacii britannici ichnographia. London.Google Scholar
Li, C., and You, H.-L. 2002. Cymbospondylus from the Upper Triassic of China. Vertebrata PalAsiatica, 40:9–16.Google Scholar
Maisch, M. W. 1997. A case against a diapsid origin of the Ichthyosauria. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 205:111–127.Google Scholar
Maisch, M. W. 1998. The temporal region of the Middle Jurassic ichthyosaur Ophthalmosaurus - further evidence for the non-diapsid cranial architecture of the Ichthyosauria. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 1998:401–414.Google Scholar
Maisch, M. W. 2001. Observations on Triassic ichthyosaurs, Part VII: New data on the osteology of Chaohusaurus geishanensis Young & Dong, 1972 from the Lower Triassic of Anhui (China). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 219:305–327.Google Scholar
Maisch, M. W. and Matzke, A. T. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie), 298:1–159.Google Scholar
Maisch, M. W., and Matzke, A. T. 2002. The skull of a large Lower Triassic ichthyosaur from Spitzbergen and its implications for the origin of the Ichthyosauria. Lethaia, 35:250–256.Google Scholar
Maisch, M. W., and Matzke, A. T. 2003. Observations on Triassic ichthyosaurs. Part XII. A new Early Triassic ichthyosaur genus from Spitzbergen. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 229:317–338.Google Scholar
Maisch, M. W., Pan, X. R., Sun, Z. Y., Cai, T., Zhang, D. P., and Xie, J. L. 2006. Cranial osteology of Guizhouichthyosaurus tangae (Reptilia: Ichthyosauria) from the Upper Triassic of China. Journal of Vertebrate Paleontology, 26:588–597.Google Scholar
Massare, J. A. 1987. Tooth morphology and prey preference of Mesozoic marine reptiles. Journal of Vertebrate Paleontology, 7:121–137.CrossRefGoogle Scholar
Massare, J. A., and Callaway, J. M. 1990. The affinities and ecology of Triassic Ichthyosaurs. Geological Society of America Bulletin, 102:409–416.Google Scholar
Motani, R. 1996. Redescription of the dental features of an Early Triassic ichthyosaur, Utatsusaurus hataii . Journal of Vertebrate Paleontology, 16:396–402.Google Scholar
Motani, R. 1997a. Redescription of the dentition of Grippia longirostris (Ichthyosauria) with a comparison with Utatsusaurus hataii . Journal of Vertebrate Paleontology, 17:39–44.CrossRefGoogle Scholar
Motani, R. 1997b. Temporal and spatial distribution of tooth implantations, p. 81–103. In Callaway, J. M. and Nicholls, E. L. (eds.), Ancient Marine Reptiles. Academic Press, San Diego.Google Scholar
Motani, R. 1999. Phylogeny of the Ichthyopterygia. Journal of Vertebrate Paleontology, 19:473–496.Google Scholar
Motani, R. 2000. Skull of Grippia longirostris: no contradiction with a diapsid affinity for the ichthyopterygia. Palaeontology, 43:1–14.Google Scholar
Motani, R., Minoura, N., and Ando, T. 1998. Ichthyosaurian relationships illuminated by new primitive skeletons from Japan. Nature, 393:255–257.Google Scholar
Motani, R. and You, ND H. 1998. Taxonomy and limb ontogeny of Chaohusaurus geishanensis (Ichthyosauria), with a note on the allometric equation. Journal of Vertebrate Paleontology, 18:533–540.CrossRefGoogle Scholar
Müller, J. 2003. Early loss and multiple return of the lower temporal arcade in diapsid reptiles. Naturwissenschaften, 90:473–476.Google Scholar
Nicholls, E. L. and Brinkman, D. B. 1995. A new ichthyosaur from the Triassic of Sulphur Mountain Formation of British Columbia, p. 521–535. In Sarjeant, W. A. S. (ed.), Vertebrate fossils and the evolution of scientific concepts. Gordon and Breach, Switzerland.Google Scholar
Osborn, H. F. 1903. The reptilian subclasses Diapsida and Synapsida and the early history of the Diaptosauria. Memoir of the American Museum of Natural History, 1:449–507.Google Scholar
Reisz, R. R., Berman, D. S., and Scott, D. 1984. The anatomy and relationships of the Lower Permian reptile Araeoscelis . Journal of Vertebrate Paleontology, 4:57–67.Google Scholar
Riess, J. 1986. Fortbewegungsweise, Schwimmbiophysik und Phylogenie der Ichthyosaurier. Palaeontographica Abteilung A, 192:93–155.Google Scholar
Sander, M. 2000. Ichthyosauria: their diversity, distribution, and phylogeny. Paläontologische, Zeitschrift, 74:1–36.Google Scholar
Schmitz, L., Sander, P. M., Storrs, G. W., and Rieppel, O. 2004. New Mixosauridae (Ichthyosauria) from the Middle Triassic of the Augusta Mountains (Nevada, USA) and their implications for mixosaur taxonomy. Palaeontographica Abteilung A, 270:133–162.Google Scholar
Shikama, T., Kamei, T., and Murata, M. 1978. Early Triassic Ichthyosaurus, Utatsusaurus hataii gen. et sp. nov., from the Kitakami massif, Northeast Japan. Science Reports of the Tohoku University, Sendai, Second Series, Geology, 48:77–97.Google Scholar
Sues, H.-D. 1987. On the skull of Placodus gigas and the relationships of the Placodontia. Journal of Vertebrate Paleontology, 7:138–144.Google Scholar
Tarsitano, S. 1982. A model for the origin of ichthyosaurs. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 164:143–145.Google Scholar
Tarsitano, S. 1983. A case for the diapsid origin of ichtyosaurs. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 1983:59–64.Google Scholar
Wiman, C. 1929. Eine neue Reptilordnung aus der Trias Spitzbergens. Bulletin of the Geological Institution of the University of Upsala, 22:183–196.Google Scholar
Young, C. C. and Dong, Z. M. 1972. Chaohusaurus geishanensis from Anhui Province. In Young, C. C. and Dong, Z. M. (eds.), Aquatic Reptiles from the Triassic of China. Academia Sinica, Institute of Vertebrate Paleontology and Paleonanthropology, Memoir 9, Beijing. (In Chinese).Google Scholar
Zhang, Q. Y., Zhao, L. S., Zhou, C. Y., Lv, T., Xie, T., Lou, X. Y., Liu, W., Sun, Y. Y., and Huang, J. Y. 2009. A Conodont-based Middle Triassic age assignment for the Luoping Biota of Yunnan, China. Science in China Series D-Earth Sciences, 52:1673–1678.Google Scholar
Zhang, Q. Y., Zhou, C. Y., Lv, T., Xie, T., Lou, X. Y., Liu, W., Sun, Y. Y., and Jiang, X. S. 2008. Discovery and significance of the Middle Triassic Anisian Biota from Luoping, Yunnan Province. Geological Review, 54:523–526. (In Chinese).Google Scholar