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[dahy-ap-sid] /daɪˈæp sɪd/
(of reptiles) having two openings in the skull behind each eye, characteristic of the subclasses Lepidosauria and Archosauria, including all living reptiles except turtles.
a diapsid reptile.
Compare anapsid.
Origin of diapsid
< New Latin Diapsida (1903); see di-1, anapsid Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for diapsid
Historical Examples
  • Their remains fall into two great groups, which are known as the diapsid and the Synapsid reptiles.

    The Story of Evolution Joseph McCabe
diapsid in Science
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.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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