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The lizards
are considered as reptiles. On this picture you can see a
Perentie Goanna which is considered as the third largest monitor
lizard. Reptiles are amniotes and tetrapods, vertebrate animals
with four feet or legs, there is four living order of reptiles,
the Squamata which includes lizards, snakes and amphisbaenids,
there is in this order around 7600 species. The Crocodilia has
23 species including alligators, crocodiles and caimans. The
Testudines has about 300 species including turtles. The
Rhynchocephalia has only 2 species, the tuatara from New Zealand
which is considered as an endangered species. On every continent
reptiles are found except Antarctica although that it is known
that reptiles like subtropical and tropical areas. Most reptiles
are oviparous which means they lay eggs but many species of the
Squamates order can also give live birth. All reptiles are
covered of scales except for the Testudines. The Hylonomus is
known to be the oldest reptile; it was about 20 to 30 cm long.
The Anapsids were considered as “true reptiles”, they form part
of the amniotes group. They had hard skull structure and
openings only for eyes and nose etc. Some think that turtles may
be surviving Anapsids because of the skull structure. |
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