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[kot-l-uh-sawr] /ˈkɒt l əˌsɔr/
any member of the extinct order Cotylosauria, comprising heavy-bodied, splay-limbed, plant-eating reptiles that arose during the Carboniferous Period and that are considered to include the ancestors of all other reptiles.
Also called root reptile, stem reptile.
Origin of cotylosaur
1900-05; < New Latin Cotylosauria, equivalent to cotyl(lus) a hollow space in the bones forming the distinctive articulation of skull and vertebrae, which orig. defined the order (masculine noun < Greek kotýlē socket, cup, anything hollow) + -o- -o- + -sauria; see -saur, -ia
Related forms
cotylosaurian, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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cotylosaur in Science
Any of a number of extinct reptiles of the group Cotylosauria or Captorhinida of the Carboniferous and Permian Periods that include the ancestors of all terrestrial vertebrates except for amphibians. Cotylosaurs evolved from early amphibians, had four sprawling legs and a long tail, and a skull without temporal openings. Also called stem reptile.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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