Maths encyclopedia and lessons  
Search

Mathematics Encyclopedia and Lessons

 
     
 

Lessons

Popular
Subjects

algebra
arithmetic
calculus
equations
geometry
differential equations
trigonometry
number theory
probability theory
more
 

References

applied mathematics
mathematical games
mathematicians
more
 
 

Anapsid

Testudines (Turtles)
Millerettid - extinct
Nyctiphruret - extinct
Pareiasaur - extinct
Procolophonoid - extinct The anapsids are a group of amniotes, characterized by skulls without openings near the temples. The only extant members are the Testudines - turtles, tortoises, and terrapins. Various other groups, however, are known from Permian and Triassic fossils. The anapsids have traditionally been treated as a subclass of the class Reptilia, but as this group is paraphyletic they are sometimes placed in a separate class Anapsida.

Most of the anapsid orders, including the millerettids , nyctiphrurets , and pareiasaurs , were extincted in the late Permian period by the Permian-Triassic extinction event. Both the procolophonoids and some ancient ancestors of the testudines managed to survive into the Triassic, and the testidunes are the only surviving order.

External links


01-04-2007 01:18:14
The contents of this article are licensed from Wikipedia.org
under the GNU Free Documentation License. How to see transparent copy