synapsid (s -n p sd) A reptile with one temporal opening on each side of the skull. Synapsids evolved in the late Permian Period and were characterized by carrying their limbs under their body and developing front teeth that were different from their back teeth. One group of synapsids, the therapsids, gave rise to the mammals. Compare anapsiddiapsidtherapsid |
ThesaurusLegend: Synonyms Related Words Antonyms
| Noun | 1. | synapsid - extinct reptile having a single pair of lateral temporal openings in the skull reptile, reptilian - any cold-blooded vertebrate of the class Reptilia including tortoises, turtles, snakes, lizards, alligators, crocodiles, and extinct forms protomammal, therapsid - probably warm-blooded; considered direct ancestor of mammals ictodosaur - intermediate in form between the therapsids and most primitive true mammals pelycosaur - large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America edaphosaurus - heavy-bodied reptile with a dorsal sail or crest; of the late Paleozoic dimetrodon - carnivorous dinosaur of the Permian in North America having a crest or dorsal sail |
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