Reptiles

The reptiles are animals Vertébrés, Tétrapode S, Amniote S, and members of the class of the Sauropside S. In the world living current, they are represented by four S:

  • the Crocodilien S (Crocodile S, Gavial S, caiman S and Alligator S): 23 S;

  • the Sphénodon S (Tuatara S of New Zealand): 2 species;
  • the Squamate S (Lizard S, Snake S and amphisbenes (" lizard-ver") : approximately: 7900 species;
  • the Testudines (Tortoise S): approximately 300 species.

The reptiles , with the direction running, gather the terrestrial animals at variable temperature (ectothermes) and with which the body is covered by scales. Formerly regarded as a scientific taxon, this regrouping proved to be nonrelevant to include/understand the evolution since the reptiles do not form a group Monophylétique but a group Paraphylétique: certain reptiles gave rise to the Oiseau X and the Reptiles mammaliens gave rise to the Mammifères.

“Reptile” means “ which crawls ”, although it is not a universal characteristic of this class.

The part of the Natural history treating reptiles names the Herpétologie (access to the lists of the herpetologists).

Description

Although having always continued to evolve/move, certain characteristics are found in all the reptiles. The current reptiles are Poïkilotherme S and preserved same the occipital Condyle located at the back of cranium and ensuring the articulation with the first vertebra, whereas in the Amphibians and the mammals, it is double. Many reptiles moult and their skin “is not recycled”. This characteristic is not almost visible any more for many species of tortoises and of Crocodilien S. Except exception (for example the Tortue lute), they preserve a skin covered with scales. Almost all the reptiles are Ovipare S (lay eggs), but some are Vivipare S or Ovovivipare S.

Except for the crocodiliens, the reptiles present a Cœur of which both ventricles are not completely separate. However, even with a ventricle not divided, the mixture of Sang arterial and venous is tiny. The tortoises, they, have two auricles and only one ventricle.

The parental protective behaviors are particularly developed in certain snakes (Pythonidae and Elapidae) like at the crocodiliens and completely absent at other species like the marine tortoises or the majority of the Lézard S.

Taxonomy

Elements of history

It is Josephus Nicolaus Laurenti (1735-1805) which, in 1768, in its thesis devoted to the poisonous function at the Reptile S and the Amphibien S, precisely defines the first the class of the Reptilia.

phylogenetic Classification

This taxon is not regarded as Monophylétique; if the fossil Reptiles mammaliens form same a Clade with the Mammifères, the other reptiles form of them another with the Oiseau X and the Dinosaures, that of the Sauropsides, brother group of the precedent within the Vertébrés Amniotes.

──o Sauropsides ├─o Chéloniens --------------| │ | └─o Diapsides ---------------| ├─o Lépidosauriens --------| │ ├─o Squamates -----------| “ Reptiles ” │ └─o Sphénodontiens ------| │ | └─o Archosauriens | ├─o Crocodiliens --------| └─o Bird X


List orders

Place des reptiles in the animal world

See too

External references

External bonds

  • Choice of vidéos of Repitiles of all the world
  • Description of the group of the reptiles and the batrachians
  • reptiles on the site of the Canadian Council of protection of Animals.

Related articles

Simple: Reptile Zh-min-nan: Pâ-thiông

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