Encyclopedia > Lepidosauria

  Article Content

Amniote

Redirected from Lepidosauria

Amniotes
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Taxon:Tetrapoda
Taxon:Amniota
Extant subgroups
Synapsida
    Mammalia (mammals)
Anapsida
    Testudines (turtles)
Diapsida[?]
    Lepidosauria
       Squamata[?] (lizards and snakes)
       Sphenodontida[?] (tuatara)
    Archosauria[?]
       Crocodilia[?] (crocodiles and alligators)
       Aves (birds)

The amniotes are a group of vertebrates, comprising the mammals, birds, and various other groups collectively referred to as reptiles. Most are adapted to a fully terrestrial existence, although some are secondarily aquatic. In contrast, amphibians are only partially terrestrial and pass through an aquatic stage. The name comes from the amniotic egg, in which the developing embryo is protected by a series of membranes and a hard shell which resists dessication. Most mammals do not lay eggs, but corresponding structures may be found inside the placenta. Most reptiles also have protective scales, which are modified in birds to form feathers.

There are three main lines of amniotes, which may be distinguished by the structure of the skull and in particular the number temporal fenetrae (openings) behind the eye. In anapsids there are none, in synapsids there is one, and in most diapsids[?] there are two.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Northwest Harbor, New York

... The racial makeup of the town is 90.49% White, 3.63% African American, 0.16% Native American, 1.05% Asian, 0.03% Pacific Islander, 2.62% from other races, and 2.03% ...

 
 
 
This page was created in 26 ms