| Noun | 1. | Anapsida - oldest known reptiles: turtles; extinct Permian formsclass Reptilia, Reptilia - class of cold-blooded air-breathing vertebrates with completely ossified skeleton and a body usually covered with scales or horny plates; once the dominant land animals anapsid, anapsid reptile - primitive reptile having no opening in the temporal region of the skull; all extinct except turtles class - (biology) a taxonomic group containing one or more orders | |