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New information on the forefin of Utatsusaurus hataii (Ichthyosauria)

Published online by Cambridge University Press:  14 July 2015

Ryosuke Motani
Ryosuke Motani*
Affiliation:
Department of Zoology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 1A1 Canada
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Abstract

Utatsusaurus hataii, an Early Triassic ichthyosaur from Japan, is represented by exceptionally well preserved materials but is poorly known because of incomplete preparation. Further preparation of the holotype and one of the paratype specimens has revealed nearly complete forefins that are pentadactyl, with no more than five phalanges in any of the digits. The first digit is not well developed, and the fifth distal carpal appears to be absent. The phalanges along the fin margin tend to be lunate; others are flattened cylinders. These findings indicate that the relationship of Utatsusaurus with other Early Triassic ichthyosaurs must be reconsidered.

Type
Research Article
Information
Journal of Paleontology , Volume 71 , Issue 3 , May 1997 , pp. 475 - 479
Copyright
Copyright © The Paleontological Society 

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References

Brinkman, D. B., Zhao, X., and Nicholls, E. L. 1992. A primitive ichthyosaur from the Lower Triassic of British Columbia, Canada. Palaeontology, 35:465–474.Google Scholar
Carroll, R. L. 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Company, New York, 698 p.Google Scholar
Chen, L.-Z. 1985. [Ichthyosaurs from the Lower Triassic of Chao County, Anhui.] Regional Geology of China, 15:139–146. (In Chinese)Google Scholar
Johnson, R. 1977. Size independent criteria for estimating relative age and the relationship among growth parameters in a group of fossil reptiles (Reptilia: Ichthyosauria). Canadian Journal of Earth Sciences, 14:1916–1924.CrossRefGoogle Scholar
Mazin, J.-M. 1986. A new interpretation of the fore-fin of Utatsusaurus hataii (Reptilia, Ichthyopterygia). Paläontologische Zeitschrift, 60:313–318.CrossRefGoogle Scholar
Mazin, J.-M., Suteethorn, V., Buffetaut, E., Jaeger, J.-J., and Helmcke-Ingavat, R. 1991. Preliminary description of Thaisaurus chonglakmanii n. g., n. sp., a new ichthyopterygian (Reptilia) from the Early Triassic of Thailand. Comptes Rendus de l'Académie des Sciences. Série 2, 313:1207–1212.Google Scholar
Motani, R. 1994. Computer aided comparisons among Early Triassic ichthyosaurs reveal smaller taxonomic diversity than was believed. Journal of Vertebrate Paleontology, 14:39A.Google Scholar
Motani, R.In press a. Redescription of the dental features of an Early Triassic ichthyosaur Utatsusaurus hataii. Journal of Vertebrate Paleontology 16.CrossRefGoogle Scholar
Motani, R.In press b. Redescription of the dentition of Grippia longirostris (Ichthyosauria) with a comparison with Utatsusaurus hataii. Journal of Vertebrate Paleontology.Google Scholar
Repossi, E. 1902. Il mixosauro degli strati triasici di Besano in Lombardia. Atti della Società Italiana di Scienze Naturali, 41:61–72.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
Wiman, C. 1929. Eine neue Reptilien-Ordnung aus der Trias Spitzbergens. Bulletin of the Geological Institution of the University of Upsala, 22:183–196.Google Scholar
Wiman, C. 1933. Über Grippia longirostris. Nova Acta Regiae Societatis Scientiarum Upsaliensis, 9:1–19.Google Scholar
Young, C. C., and Dong, Z.-M. 1972. [Chaohusaurus geishanensis from Anhui Province], p. 11–14. In Young, C. C. and Dong, Z.-M. (eds.), [Aquatic reptiles from the Triassic of China]. Academia Sinica, Institute of Vertebrate Paleontology and Paleoanthropology, Memoir, 9. (In Chinese)Google Scholar