Английская Википедия:Atheris desaixi

Содержание

Текст

Текст

Текст

Текст

Текст

Текст

Текст

Текст

Текст

Atheris desaixi, commonly known as the Mount Kenya bush viper, Ashe's bush viper, or Desaix's bush viper, is a venomous species of viper endemic to Kenya, where only two isolated populations are known. It is known for its striking black and yellow coloration. No subspecies are currently recognized.

Etymology

This species, A. desaixi, is named in honor of Frank DeSaix, an American Peace Corps volunteer who collected the first specimen.

Description

Adults of A. desaixi average 40–60 cm (about 16-24 inches) in total length (including tail), with a maximum total length of Шаблон:Convert. Newborns measure Шаблон:Convert in total length. In Ashe's original 1968 description, adults were reported to grow to an average 49–68 cm (about 19-27 inches) total length, with a head and body length of Шаблон:Convert and a tail length of Шаблон:Convert.

The eyes are set well forward in the head and are surrounded by 14–17 scales. Interorbital scales number 8–11. The eye is separated from the nasal by two to three scales and from the supralabials by two. Upper labials: 10–12. Sublabials: 11–14. The rostral scale is not as wide as it is long, while its upper margin is highest at the center. The rostral is also accompanied by an even number of suprarostrals. The superciliary scales above the eyes are not enlarged (as opposed to A. ceratophora). The nasal scale is round and single, or partially divided.

Midbody, the dorsal scale rows number 24–31. The dorsal scales are short and heavily keeled. However, on the upper dorsals the keels terminate before the end of each scale. On the lower dorsals, the keels are serrated (like in Echis). The ventral scale count is 160–174. In females the subcaudals number 41–54. One male specimen had 53 subcaudals.

The color pattern consists of a greenish-black to charcoal-black ground color, while each scale is tipped with yellow or yellowish-green, giving the animal a speckled appearance. Some scales have more of this color to them and form a series of loops along the sides of the body. These loops may fuse into zigzag patterns posteriorly, fading again on the tail. Anteriorly, the venter is yellow or yellowish, fading towards a purplish-black towards the rear and under the tail, except for the tip that is blotched with yellow. Juveniles are mainly yellow with a white tipped tail. This darkens as they grow until they reach the adult color phase at a total length of about Шаблон:Convert.

Distribution and habitat

There are two isolated populations of A. desaixi in Kenya: one in the forests at Chuka, south-eastern Mount Kenya, and the other near Igembe in the northern Nyambeni range. The type locality is listed as "near Chuka, Lat. 0° 20' S, Long. 37° 35' E, in rain forest at an altitude of c. Шаблон:Convert", Kenya.

The original specimens, for which field notes were taken, were found in dense rain forest at Шаблон:Convert, collected in clearings and along pathways in the dense foliage about Шаблон:Convert above the ground. The conditions were very humid and all specimens were collected within a Шаблон:Convert radius. In this environment, their coloration offers them an excellent camouflage, making them very difficult to spot.

Behavior

Little is known of the behavior of A. desaixi. It is obviously arboreal, moving slowly and deliberately among the branches of its habitat as other Atheris species do, but it is unknown when daily peak activity occurs. In captivity, it is just as willing to accept food during the day as at night.

When captured, it will strike readily and struggle vigorously in the hand. It may also perform a characteristic, stridulating threat display, in which counterlooped coils and the lower serrated, keeled scales are rubbed against one another to produce a loud hissing noise. However, captive specimens soon calm down and this behavior is lost.

Feeding

A. desaixi is reported to be an opportunist, preying on amphibians, rodents and small birds.

Reproduction

A gravid female specimen of A. desaixi found in the Nyambeni range is reported to have given birth to 13 offspring in the month of August. Newborns measured Шаблон:Convert in total length.

Interactions with humans

Conservation status

As of 2019, the species A. desaixi is listed as "Endangered" on the IUCN Red List of Threatened Species. The species is listed in Appendix II of CITES meaning international trade is regulated through the CITES permit system.

Snakebites

The Kenyan who collected the first specimens was bitten by an adult, with a single fang penetrating his right index finger. There was significant swelling and pain. A tourniquet was applied and an unknown antivenin was administered, after which the patient made a full recovery. It is doubtful, however, that the antivenin made any difference in this case, for no antivenin is known to be effective. Nevertheless, since these snakes are relatively large (for Atheris) and their venom is known to contain powerful anticoagulants, a bite should be taken seriously. Poor coagulation may even require blood transfusions.

Further reading

• Ashe, James (1968). "A new bush viper". Journal of the East African Natural History Society and National Museum, Nairobi 27: 53–59. (Atheris desaixi, new species).
• Hedges, Norman G. (1983). Reptiles and Amphibians of East Africa. Nairobi: Kenya Literature Bureau. 139 pp.

External links

• CoP13, Prop. 30 at CITES. Accessed 8 October 2006.
• Mount Kenya bush viper (Atheris desaixi ), Kenya at Dr. Zoltan Takacs Homebase. Accessed 9 October 2006.

Шаблон:Taxonbar