Any of a group of chiefly extinct reptiles that first emerged in the early Permian Period and are characterized by a skull with no openings in the temporal region. Modern turtles and tortoises may be surviving members of this group, or they may be descendants of diapsids that lost their skull openings.
extinct reptile having a single pair of lateral temporal openings in the skull
Find another word for synapsid. In this page you can discover 4 synonyms, antonyms, idiomatic expressions, and related words for synapsid, like: anapsid, diapsid, therapsid and synapsid reptile.