n. Any of a group of amniote vertebrates that are characterized by two openings in the temporal region on each side of the skull. The first diapsids emerged in the Pennsylvanian Period, and their descendants include the lizards, snakes, crocodiles, dinosaurs, pterosaurs, birds, and, in some classifications, the turtles. [New Latin Diapsida, taxon name : DI-1 + Greek hapsis, hapsid-, arch (from the two temporal openings on each side of the skull ); see APSIS.] di·apsid adj. |
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