cotylosaur
(kŏtˈl-ə-sôrˌ)
noun Any of an extinct order (Cotylosauria) of massive primitive reptiles of the Carboniferous and Permian periods that included the ancestors of all of the reptiles. Also called root reptile, stem reptile.
Origin:
Origin: Greek kotulē, hollow object, socket
Origin: + Greek sauros, lizard
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