ichthyosaur

American  

[ik-thee-uh-sawr] / ˈɪk θi əˌsɔr /

noun

1. any fishlike marine reptile of the extinct order Ichthyosauria, ranging from 4 to 40 feet (1.2 to 12 meters) in length and having a round, tapering body, a large head, four paddlelike flippers, and a vertical caudal fin.

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ichthyosaur British  

/ ˈɪkθɪəˌsɔː, ˌɪkθɪəˈsɔːrəs /

noun

1. any extinct marine Mesozoic reptile of the order Ichthyosauria, which had a porpoise-like body with dorsal and tail fins and paddle-like limbs See also plesiosaur

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ichthyosaur Scientific  

/ ĭk′thē-ə-sôr′ /

1. Any of various extinct sea reptiles of the genus Ichthyosaurus and related genera, that had a medium-sized to large dolphin-like body with a dorsal fin, four flippers, and a large, crescent-shaped tail. The head had a long beak with sharp teeth, large eyes and earbones, and nostrils near the eyes on top of the skull. Ichthyosaurs were most common and diverse in the Triassic and Jurassic Periods and died out well before the end of the Cretaceous.

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Other Word Forms

• ichthyosaurian
  adjective
• ichthyosauroid
  adjective

Etymology

Origin of ichthyosaur

First recorded in 1820–30; see origin at ichthyosaurus

Example Sentences

Moore had discovered an ichthyosaur in Dorset's cliffs and invited Sir David to be part of the excavation.

From BBC • May 8, 2026

"Bits of ichthyosaur are rare enough, so even if it was a piece of ichthyosaur it would have been a fantastic day," he said.

From BBC • Apr. 22, 2026

Researchers identified several anatomical traits in Xiphodracon that have never been documented in any other ichthyosaur.

From Science Daily • Feb. 24, 2026

A remarkably complete skeleton uncovered along the UK's Jurassic Coast has been identified as a previously unknown species of ichthyosaur -- a group of prehistoric marine reptiles that once dominated the world's oceans.

From Science Daily • Feb. 24, 2026

The skin of the ichthyosaur was smooth like that of a whale, and its food was largely fish and cephalopods, as the fossil contents of its stomach prove.

From The Elements of Geology by Norton, William Harmon