Caseasauria

Taxobox
name = Caseasaur
fossil_range = Early Permian - Late Permian

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image_width = 250px
image_caption = "Ennatosaurus tecton" from the Late Permian of Russia
regnum = Animalia
phylum = Chordata
subphylum = Vertebrata
classis = Synapsida
ordo = Pelycosauria
subordo = Caseasauria
subordo_authority = Williston, 1912
subdivision_ranks = Genera and Families
subdivision =
Caseidae
Eothyrididae ?"Phreatophasma"The Caseasauria are one of the two main clades of early synapsids, the other being the Eupelycosauria. They are currently known only from the Permian, and include two superficially different families, the small insectivorous or carnivorous Eothyrididae, and the large herbivorous Caseidae

These two groups share a number of [http://tolweb.org/notes/?note_id=466 specialised features] associated with the morphology of the snout and external naris and it is likely that the latter evolved from the former.

The ancestors of Caseasaurs can be traced back from an insect eating or an omnivorous reptile-like synapsid from the Pennsylvanian time of the Carboniferous, that resembles "Archaeothyris". The Caseasaurs were abundant and successful during the later part of the early Permian epoch. But by the middle Permian, the Caseasaurs became less abundant because of the evolving, more successful therapsids and by late Permian, they were facing extinction. The last Caseasaurs became extinct in the Permian–Triassic extinction event; no species of Caseasaurs made it to the Triassic Period.

ee also

* Evolution of mammals
* Vertebrate paleontology
* Permian tetrapods

References

* Reisz, R. R., 1986, "Handbuch der Paläoherpetologie – Encyclopedia of Paleoherpetology, Part 17A Pelycosauria" Verlag Dr. Friedrich Pfeil, ISBN 3-89937-032-5
* Laurin, M. and Reisz, R. R., 1997, [http://tolweb.org/accessory/Synapsid_Classification_&_Apomorphies?acc_id=466 Autapomorphies of the main clades of synapsids]

External links

* [http://www.palaeos.com/Vertebrates/Units/Unit390/100.html Palaeos Vertebrates 390.100 Synapsida]