[dahy-ap-sid] 
| 1. | (of reptiles) having two openings in the skull behind each eye, characteristic of the subclasses Lepidosauria and Archosauria, including all living reptiles except turtles. |
| 2. | a diapsid reptile. |
| di·ap·sid (dī-āp'sĭd) n. Any of various reptiles having a skull with two pairs of temporal openings and including the lizards, snakes, crocodiles, dinosaurs, and pterosaurs. [New Latin Diapsida, former subclass name : di-1 + Greek hapsis, hapsid-, loop, arch; see apsis.] di·ap'sid adj. |
| diapsid (dī-āp'sĭd) Pronunciation Key
Any of various reptiles having a skull with two pairs of temporal openings. Diapsids evolved in the Permian Period and grew longer and better-developed hindlimbs than forelimbs (unlike therapsids). Diapsids evolved into the archosaurs (including the dinosaurs and their descendants the birds) and all modern reptiles except turtles. Compare anapsid, synapsid, therapsid. |
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