Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
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.
[New Latin Anapsida, former subclass name : an- + Greek hapsis, hapsid-, arch (in reference to their lack of temporal openings); see apsis.]
Switch to new thesaurus
|Noun||1.||anapsid - primitive reptile having no opening in the temporal region of the skull; all extinct except turtles|
reptile, reptilian - any cold-blooded vertebrate of the class Reptilia including tortoises, turtles, snakes, lizards, alligators, crocodiles, and extinct forms