Utatsusaurus

Utatsusaurus
Temporal range: Early Triassic, 248–245 Ma
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Fossil
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: †Ichthyopterygia
Family: †Utatsusauridae
McGowan & Motani, 2003
Genus: †Utatsusaurus
Shikama et al., 1978
Type species
†Utatsusaurus hataii
Shikama et al., 1978

Utatsusaurus hataii is the earliest-known ichthyopterygian which lived in the Early Triassic period (c. 245–250 million years ago). It was nearly 2.5–3 metres (8.2–9.8 ft) long with a slender body.[1][2] The first specimen was found in Utatsu-cho (now part of Minamisanriku-cho), Miyagi Prefecture, Japan. It is the only described species in the genus Utatsusaurus and the only member of the family Utatsusauridae.[3] The name Utatsusaurus was given after the city.[4] The fossils have been found from the Early Triassic Osawa Formation of Miyagi Prefecture, Japan and British Columbia, Canada.[5]

Utatsusaurus is one of the most primitive grades of ichthyosaurs, a basal ichthyosaur.[6][7]

  1. ^ Cite error: The named reference Y21 was invoked but never defined (see the help page).
  2. ^ Motani, R.; Minoura, N.; Ando, T. (1998). "Ichthyosaurian relationships illuminated by new primitive skeletons from Japan". Nature. 393 (6682): 255–257. doi:10.1038/30473. S2CID 4416186.
  3. ^ Maisch, M. W. (2010). "Phylogeny, systematics, and origin of the Ichthyosauria – the state of the art" (PDF). Palaeodiversity. 3: 151–214.
  4. ^ Shikama, T.; Kamei, T.; Murata, M. (1977). "Early Triassic ichthyosaurs, Utatsusaurus hataii gen. et sp. nov., from the Kitakami Massif, Northwest Japan". Science Reports of the Tohoku University. Second Series, Geology. 48 (1): 77–97.
  5. ^ Motani, Ryosuke (1999). "Phylogeny of the Ichthyopterygia" (PDF). Journal of Vertebrate Paleontology. 19 (3): 473–496. doi:10.1080/02724634.1999.10011160. Archived from the original (PDF) on 2012-04-15.
  6. ^ Cite error: The named reference motani1997 was invoked but never defined (see the help page).
  7. ^ Motani, R. (2005). "Evolution of fish-shaped reptiles (Reptilia : Ichthyopterygia) in their physical environments and constraints" (PDF). Annual Review of Earth and Planetary Sciences. 33: 395–420. doi:10.1146/annurev.earth.33.092203.122707. Archived from the original (PDF) on 2017-05-17.