Bipes (genus)
Fünffingerige Handwühle ( bipes biporus )
The hand digging are small, strange -looking reptile of the genus bipes. Bipes is the only genus in the family of two-foot - amphisbaenians ( Bipedidae ). The hand rooting remember a large earthworm with two mole -like hands, have no other limbs and crawl or dig through the sand floor of their semi -desert habitats Mexican.
The name component " dig ", the appearance and lifestyle can lead to confusion with the not more closely related amphibian from the order of caecilians ( Gymnophiona ) lead, which are also referred to Germans as rooting ( caecilians ).
Features
Hand rooting around 20 centimeters (approx. 17-24 cm) long, have a " worm-like " body with regular transverse stripes and have a head scalation on from small, smooth horny plates. While their hind legs are atrophied, they have a front stub -like pair of arms with well-developed, provided with long claws hands. This distinguishes them from amphisbaenians other genres that are completely gliedmaßenlos. The eyes are set quite far forward on the blunt rounded head and are very small; the sense of sight is reduced. Ear holes are not present. The tongue is bicuspid and can be protruded. Like all amphisbaenians they crawl straight forward ( and backwards! ) Without meander like other legless lizards her body sideways. Another special feature is that they use only their left lung for breathing.
Way of life
The hand digging are adapted to a grave lifestyle. This is suggested by their smooth scales on the head, back formed their extremities, reduced their sense of sight and their grave hands down. As habitats are sparsely covered, sandbödige dry biotopes. Hand rooting feed on insects and other invertebrates, particularly ants and termites. To this end, they also penetrate into the buildings of these insects.
The males have a copulatory organ, two hemipenes. Like most reptiles lay hands rooting eggs. They do this within termite mounds.
Dissemination
The occurrence of the species is limited to three today disjoint areas in western Mexico, on the one hand to the southwest of the Baja California peninsula ( bipes biporus ), on the other, two small areas on the west coast of Mexico, so on the other side of the Gulf of California ( bipes canaliculatus, bipes tridactylus ). The spatial separation of the partial areas on the two sides of the Gulf of California is due to the special geological development of the region. Today's Baja California was formerly completely connected to the mainland of Mexico, before separated out the narrow landmass by the continental drift, drifted to the northwest and so gave rise to the Gulf of California.
System
The lineage historical classification of amphisbaenians within the reptiles is still controversial (see also: Squamata ). The Bipedidae family is considered by molekubarbiologischen studies as a sister taxon of the authentics amphisbaenians ( Amphisbaenidae ) plus the pointed tail amphisbaenians Trogonopidae.
This cladogram shows the position of the two-foot - amphisbaenians within the amphisbaenians:
Dual Foot amphisbaenians ( Bipedidae ), the only genus bipes
Actual amphisbaenians ( Amphisbaenidae )
Spitzschwanz - amphisbaenians ( Trogonopidae )
Florida amphisbaenians ( Rhineuridae ), the only way Rhineura floridana
Within the genus bipes, the only genus in the family Bipedidae, three types are distinguished:
- Bipes biporus Cope, 1894 - Five Fingered Handwühle
- Bipes canaliculatus Latreille in Sonnini & Latreille, 1801 - Four Fingered Handwühle
- Bipes tridactylus Duges, 1894 - Three Fingered Handwühle