Euryapsida

A euryapsid skull.

Euryapsida is a polyphyletic (unnatural, as the various members are not closely related) group of reptiles that are distinguished by a single temporal fossa, an opening behind the orbit, under which the post-orbital and squamosal bones articulate. They are different from Synapsida, which also have a single opening behind the orbit, by the placement of the fenestra. In synapsids, this opening is below the articulation of the post-orbital and squamosal bones. It is now commonly believed that euryapsids are in fact diapsids (which have two fenestrae behind the orbit) that lost the lower temporal fenestra. There are no surviving descendants of the euryapsids.

The term Enaliosauria was once used for ichthyosaurs and plesiosaurs combined as well.[1]

Ichthyosaur

Examples are:

The group no longer contains:

See also

References

  1. ↑ http://www.merriam-webster.com/dictionary/enaliosauria
This article is issued from Wikipedia - version of the 7/25/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.