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Utatsusaurus
Utatsusaurus
'An artist's representation of Utatsusaurus.'

Distribution

Japan and Canada

Classification

Ichthyosauria

Meaning of name

Lizard from Utatsugyoryu in Japan

Named by

Shikama, Kamei and Murata, 1998

Time

Olenekian stage of the early Triassic

Size

3 metres (10 ft)

Lifestyle

Carnivore

Species

U. hataii

 Utatsusaurus was an ichthyosaur from what is now Japan and Canada.  It lived during the early Triassic.

HistoryEdit

This, the earliest-known ichthyosaur, was found in 1982 in Japan, but it was not until a study of the skeleton was published in 1998 that is significance as the most primitive of the group was noted.

DescriptionEdit

Like most primitive ichthyosaurs it swam by undulations of its body rather than by sweeps of the tail, and it probably inhabited the shallow waters of the continental shelf.

FeaturesEdit

The skull is rather broad and tapers gradually towards the snout, unlike the narrow jaws of most other ichthyosaurs.  The teeth are small for the size of the skull and arranged in a groove - a primitive feature.  Its paddles are small and unusually, the hindlimb is bigger than the forelimb.  The paddle is made up of four fingers, unlike the usual five found in other ichthyosaurs.  Its undulating swimming action is shown by the large number of very thin narrow vertebrae, making for a very flexible body.