therapsid

the·rap·sid  (th-rpsd)

n.

Any of various reptiles of the order Therapsida of the Permian and Triassic periods, many of which are considered to be direct ancestors of mammals.

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[From New Latin Thrapsida, order name : Greek thr, wild animal; see theropod + Greek hapsis, hapsid-, arch, vault (from the enlarged lower temporal opening characteristic of the order); see apsis.]

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the·rapsid adj.

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therapsid  (th-rpsd)

An advanced type of synapsid reptile that evolved in the Permian Period. Therapsids further differentiated their dentition into nipping, biting, and crushing teeth, and (unlike diapsids) had forelimbs that were more greatly developed than hindlimbs. Therapsids include the so-called mammallike reptiles of the Permian and Triassic Periods, as well as mammals. Compare anapsiddiapsidsynapsid

Thesaurus

Noun

1.

therapsid - probably warm-blooded; considered direct ancestor of mammals protomammal synapsid, synapsid reptile - extinct reptile having a single pair of lateral temporal openings in the skull order Therapsida, Therapsida - extinct mammal-like reptiles found inhabiting all continents from the mid Permian to late Triassic Chronoperates paradoxus - shrew-sized protomammal from the Alberta region of Canada; from about 55 million years ago (much more recent than other mammal-like reptiles) cynodont - small carnivorous reptiles dicynodont - a kind of therapsid