Lizard

Lizards is the biologically non-unique name for a taxon belonging to the reptiles. The most common definitions are the lizards either as subordination to the Schuppenkriechtieren or arrange them all reptiles groups living today with the exception of turtles. The first group is the scientific name Lacertilia assigned, the second named the name Sauria (Greek σαῦρος sauros, lizard ',' Salamander '). Confusingly, the name " Sauria " but also used synonymously with Lacertilia, so that you can see only on the basis of the context, is used in what sense the name.

Etymology

The term was created in 1816 by Lorenz Oken from the shortening of lizard. In the third part of his work textbook of natural history, it serves as an alternative name for his order " bird amphibians ", which includes both crocodiles, as well as numerous species which are summarized in the classical system still in use today under the name of Lacertilia.

Lizards in the narrow sense

Lizards ( Lacertilia ) are in classical systematics a subordination of the Squamata. The other suborder of Squamata is that of snakes. In contrast to this, most lizards have fully developed limbs. An exception is the crawl. But the Lizards differ from snakes by a number of other features. Snakes, for example, only one row of ventral ( belly side lying ) scales, while the lizards have several rows of scales.

There are four partial orders:

  • Iguana -like ( Iguania ): iguanas, Agamas, Chameleons, etc.
  • Gecko -like ( Gekkota ): Geckos and Related
  • Skinkartige ( Scincomorpha ): skinks, lizards, Girdle, etc.
  • Stealth -like i.w.S. ( Anguimorpha ): Sneaking, monitor lizards, Heloderma etc.

From the point of view of cladistics is at the lizards in the sense of the classical system to a paraphyletic group; the juxtaposition of snakes and lizards is not tenable, because snakes are apparently more closely related to a particular lizard group, namely the monitors when the monitor lizards lizards with other groups. This in turn implies that snakes probably emerged from waranartigen lizards and thus actually own " lizards " are.

Lizards thus provide a degree of organization (English: grade) in the evolution of Squamata is, which does not necessarily closely related Schuppenkriechtieren of the same degree of organization ( " lizard " ) must be present and not necessarily a close relationship of Schuppenkriechtieren different organizational levels ( eg as certain " lizards " and snakes ) is excluded.

Lizards in the broader sense

Referring also tuatara, crocodiles ( " crocodilians " ) in the term with one, so use it in the original, Oken'schen sense, referred to as " lizard" nurmehr a four-legged reptile with rather long tail and rather short neck, that stands for the typical " iguanas habitus". This habit is evolutionarily very old. Already the earliest reptiles such as Hylonomus from the Carboniferous possessed him, with them this was in turn inherited from their amphibious ancestors.

In this respect, it is not surprising that all throughout the earth's extinct, rather large breed amphibians and reptiles are called dinosaurs colloquially popular - scientific context. For amphibians, such as Seymouria, is also called " Ur -dinosaur " is used.

Classification of the lizards in the narrow sense

Subordination lizards ( Lacertilia )

  • Partial order iguana -like ( Iguania ) Family Agamidae ( Agamidae )
  • Family Chamaeleonidae ( Chameleons)
  • Family Iguanidae ( iguanas )
  • Family Corytophanidae ( basilisks and relatives )
  • Family Crotaphytidae ( collared lizards )
  • Family Hoplocercidae
  • Family Leiocephalidae ( mask iguanas )
  • Family Leiosauridae
  • Family Liolaemidae
  • Family Opluridae ( smoothhead iguanas )
  • Family Phrynosomatidae ( spiny lizards )
  • Family Polychrotidae ( Anoles )
  • Family Tropiduridae ( Erdleguane, Kiel tail iguanas )
  • Family Gekkonidae ( geckos )
  • Family Pygopodidae (fins feet )
  • Family Dibamidae (snake crawl )
  • Family Scincidae ( skinks )
  • Family Lacertidae ( lizards )
  • Family Teiidae ( rail lizards )
  • Family Cordylidae ( belt lizards )
  • Family Gerrhosauridae ( plated lizards )
  • Family Gymnophthalmidae
  • Family Xantusiidae ( night lizards )
  • About Family Sneak -like i.e.S. ( Diploglossa ) Family Anguidae ( Stealth )
  • Family Anniellidae (marigold Sneak )
  • Family Xenosauridae ( cusp lizards )
  • Family Varanidae ( monitor lizards )
  • Family Lanthanotidae ( Taubwarane )
  • Family Helodermatidae ( Heloderma )
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