Eryx jaculus
Western boa from Pylos ( Peloponnese / Greece)
The Western sand boa ( Eryx jaculus ) is a species of the family of boas ( Boidae ) with a body length up to about 80 centimeters. It is the only snake that is endemic in a larger area of Europe; only on the northwest shore of the Caspian Sea can be found in addition the Eastern sand boa ( Eryx miliaris ).
- 4.1 Research history and fossil record
- 4.2 Outer systematics
- 4.3 subspecies
- 6.1 Notes and references
- 6.2 Literature
- 6.3 External links
Features
The Western sand boa has a yellow to light brown ground color, with brown to black irregular patches and bands. The females are about 46-71 cm long, the male 30-46 cm, maximum length 83.8 inches as measured in an individual. Relatives of island populations, for example, from the Mediterranean island of Corfu, mostly remain significantly smaller with a maximum length of 60 cm. The tail is rather short, it accounts for about seven to ten percent of the body length. The body is stocky and the head is not separated from the body.
A striking feature of the shape of the head from the curved and elongated crest shield ( parietal ) is formed grave projection on the otherwise rounded head tip. A Parietalkamm is poorly developed and hardly recognizable. Unlike the Eastern sand boa, in which the eyes are at the top of the head, they have at the Western boa a large distance from each other and sit on the sides of the head. The head narrows to the mouth downwards sharply, so that the mouth edges sunk considerably and lying under the eyes Subocularia are not visible from above.
The rostral is broad trapezoidal and extends far beyond the mental addition of the mandible. The snake also has two Internasalia ( shields between the nostrils ) and two to three post - Internasalia directly behind it. Between these and the interorbital region ( between the eyes ) are two to seven and in the direct line between the eyes two to five head shields. To the eyes are six to twelve Circumocularia arranged and between Präocularia and Postnasalia are two to three Lorealia. The mouth gap is bounded at the top by seven to eleven supralabials.
The body has 41 to 57 longitudinal rows posterior scales at its thickest point. The scales are formed largely smooth, a weak Kielung occurs in the last third of the torso and on the tail top. The throat has very small, elongated scales that go over the neck in the trained as a wide range of 161-200 ventral scales ( Ventralia ). The large and undivided anal shield close to 15 to 36 Subcaudalia. To the side of Analschildes are the remains of rudimentary hind limbs clearly visible as an after spurs, which are designed to be larger in the males than in the females.
Distribution and habitat
The distribution area of the Western boa ranges from Iran and Iraq to the Middle East and North Africa to the Balkans and South Eastern Europe and the Trans Caucasus to the Caspian Sea. There, the distribution area of the Eastern boa joins ( Eryx miliaris ), which goes as far as Central Asia.
As a preferred habitat type dry areas with loose sand layers. Vacant rodent burrows are accepted subject to its own courses to be built.
Way of life
Activity
The activity of the Western boa is mainly dependent on the particular day temperature and thus regional differences. A wintering takes place mainly in the high mountain regions of the Caucasus, where the snakes to retire in the period from November to March in underground wintering areas that are sometimes several feet deep in the ground. In contrast, there is the daily temperatures are only very short or no overwintering stages, especially since in Libya and Egypt in January or between 10 and 20 ° C in Southeastern Europe, Asia Minor and North Africa. In the low mountain ranges of Tunisia and northern Algeria it comes to short-term overwintering.
The daily activity is also temperature dependent. In seasons in which the daily mean temperature is below about 20 ° C, the Western boa is almost exclusively diurnal, at higher temperatures, they shifted the activity to the cooler morning or in the evening twilight. At temperatures above 30 ° C, the snake is very rare to find in the open and hidden usually in their shelter under rocks or in burrows.
Nutrition
The food of the snake covers depending on their body size and dietary spectrum of their habitat mainly small mammals, lizards and large insects; In addition to ground- nesting birds and larger slugs are captured. The snake lurks the spoils in their hideout on or leaves it especially at night to actively hunt.
The prey animals are packed like most giant snakes with their mouths and then very quickly embraced by the body until they are suffocated. Then they are completely swallowed.
Reproduction and Development
A female mates regional variations from the end of March to July with several males. After a gestation period of about four months, the mother gives birth to live young ( Ovoviviparie ), which are surrounded by transparent egg cases, which are then pierced.
Predators
About potential predators of the Western boa, little is known. There is obviously no predators, who specializes in the predation of this kind, on the other hand, is to assume that particular juveniles and small individuals are regularly captured by predators such as foxes, dogs and cats or birds of prey and owls. In barn owls in Israel skeletal remains of the Western boa were detected in Gewöllen, though not often. In addition, sand boas make probably also for larger snakes potential prey dar.
System
Research history and fossil record
The Western boa was first described in 1758 by Carolus Linnaeus as Anguis jaculus scientifically. The Terra typica was about Egypt, which used for this description type specimen is no longer available. 1801 ordered the French naturalist Guillaume- Antoine Olivier the type based on own collection copies in the genus Boa as a B. turcica. In 1831, the classification in 1803 by François -Marie Daudin described and which still exists genus Eryx was made by Karl Eduard Eichwald familiaris as Eryx.
Fossil is the Western boa or very closely related species occupied since the Miocene. In this common fossils that are likely to be concerned kind, including in Spain and thus found outside the present distribution area. On the basis of these findings and the derived also from Spain Primitivus discovery of a type known as Eryx is concluded that the range of the species covered the entire Mediterranean in the Miocene.
Outer systematics
The Western boa is classified as a species in the genus of the Real Sand Boas ( Eryx ). Within the genus, especially skeletal and scale characteristics for species differentiation and for systematic studies are used. The Western boa is therefore very likely the sister species of the Indian sand boa ( Eryx johnii ) dar. Both together make within the genus, the most derived forms represent the most closely related species are the large sand boa ( Eryx tataricus ) and the Eastern sand boa ( Eryx miliaris ).
Other types
Eastern sand boa ( Eryx miliaris )
Large sand boa ( Eryx tataricus )
Indian sand boa ( Eryx johnii )
Western sand boa ( Eryx jaculus )
Subspecies
From the Western boa different numbers of subspecies are described depending on the source, which differ mainly due to the scale shape and number ( Pholidose ). After a comprehensive analysis of all described subspecies Tokar and fruit in 1993 come to the view that only two subspecies should be recognized:
- E. j. jaculus than nominate in North Africa with an Arab area of distribution to the Suez Canal
- E. j. turcicus as a subspecies in South Eastern Europe, Asia Minor, the Caucasus, Iran and Iraq.
Within this, the formerly described as a subspecies of E. j. familiaris and E. j. urmianus of E. j. turcicus slammed and combined into a single subspecies. E. j. turcicus well positioned in their characteristic features is a very diverse form which may have regional differences.
Threat and protection
The species is listed in CITES Convention in Annex 2 and Annex A of the EU Wildlife Trade Regulation. This means that the animals may not be taken from the wild, owners of these animals are required to have a Certificate of Origin (CITES ). They are also added to the Fauna-Flora -Habitat Directive of the European Union in Annex 4 and are particularly protected since 1998 by the Federal Nature Conservation Act.
In private terraria these animals are rarely held and therefore rarely bred.