[ ik-thee-uh-sawr ]
/ ˈɪk θi əˌsɔr /
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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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Origin of ichthyosaur

First recorded in 1820–30; see origin at ichthyosaurus
ich·thy·o·sau·ri·an, adjective, nounich·thy·o·sau·roid, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for ichthyosaur


ichthyosaurus (ˌɪkθɪəˈsɔːrəs)

/ (ˈɪkθɪəˌsɔː) /

noun plural -saurs, -sauruses or -sauri (-ˈsɔːraɪ)

any extinct marine Mesozoic reptile of the order Ichthyosauria, which had a porpoise-like body with dorsal and tail fins and paddle-like limbsSee also plesiosaur
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for ichthyosaur

[ ĭkthē-ə-sôr′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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