Blind snake-like
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| Cope , 1864 |
The blind snake-like (Typhlopoidea or Scolecophidia) represent a taxon of the snakes with about 280 species, which, depending on the author, is viewed as a superfamily or a suborder . They are compared to the real snakes (Alethinophidia), whose sister group they represent , as primeval species within the snakes living today .
features
Blind snakes are usually small snakes no longer than ten centimeters in length. The body is worm-like, round and smooth scaly. The head is compact and flattened and covered with a few scales larger than those of the body. The rostral shield used when digging is particularly large, extends to the top of the head and is partially beak-like. The eyes are very small, almost completely covered by the head shields and, in contrast to the Alethinophidia, not covered by a scutum oculare (glasses). The mouth is below and has only a small gap. Unlike most higher snakes, the lower jaws are firmly connected. The tail ends in a thorn that is used for anchoring and pushing off the ground.
Way of life
All blind snakes have a burrowing way of life, with the worm-shaped body, large rostral and tail hook allowing rapid digging in the earth. The non-poisonous snakes feed on small invertebrates.
Systematics
External system
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| Position of the Scolecophidia within the snakes according to Longrich et al. 2012 |
Osteological analyzes of fossil and recent snake taxa show the blind snake-like as the most basic group of snakes living today; only the Cretaceous genera Najash and Coniophis are considered to be even more original. Probably Najash and the precursor of the blind snake-like as well as the rest of the snakes separated around 130 million years ago. The blind serpentines separated from the rest of this line around 120 million years ago. They have been found for the first time in fossil form since the beginning of the Paleocene around 65 million years ago.
However , according to a new study of the phylogeny of the scaly creepers , the blind snakes are a paraphyletic group; H. the taxon does not include all descendants of the youngest common ancestor. Slender blind snakes (Leptotyphlopidae) and blind snakes (Typhlopidae) are at the base of the snake tree and together form the sister group of the American blind snakes (Anomalepidae) and the rest of the snakes (Alethinophidia). This family tree suggests that all snakes descend from burrowing, underground forms and that most of today's snakes have subsequently adapted to a terrestrial way of life.
Internal system
The blind snakes include five families with twelve genera and over 300 species.
- Family: Blind snakes (Typhlopidae) with six genera and over 230 species
- Family: American blind snakes (Anomalepidae) with four genera and 18 species
- Family: Slender blind snakes (Leptotyphlopidae) with 12 genera and over 90 species
- Family: Gerrhopilidae (15 species)
- Family: Xenotyphlopidae (2 species)
literature
- Nicholas R. Longrich, Bhart-Anjan S. Bhullar, Jacques A. Gauthier: A Transitional Snake from the Late Cretaceous Period of North America. In: Nature , 2012. doi : 10.1038 / nature11227 , pp. 1-4.
- Mark O'Shea: Boas and Pythons of the World . New Holland Publishers, 2007, ISBN 978-1-84537-544-7 , pp. 15-16 .
- Dieter Schmidt: Atlas snakes . Nikol, Hamburg 2009, ISBN 978-3-86820-011-9 , pp. 45 .
Individual evidence
- ↑ a b Longrich et al. 2012, p. 3.
- ↑ John J. Wiens, Carl R. Hutter, Daniel G. Mulcahy, Brice P. Noonan, Ted M. Townsend, Jack W. Sites, Jr & Tod W. Reeder: Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species. Biol. Lett. doi : 10.1098 / rsbl.2012.0703