Common toad viper
| Common toad viper | ||||||||||||
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Common toad viper ( Causus rhombeatus ) |
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| Scientific name | ||||||||||||
| Causus rhombeatus | ||||||||||||
| ( Lichtenstein , 1823) |
The Common toads Viper ( Causus rhombeatus ), also Argyle Viper toads , frogs Otter or Common toads Otter called, is a viper from the subfamily of the Real vipers and belongs to the genus of causinae ( Causus ).
features
Causus rhombeatus reaches a total length between 60 to 90 cm. The body is slightly stocky and often slightly flattened on the sides. The head is relatively short, has a rounded snout and is moderately set off from the neck. The pupils are round when exposed to light. The basic color of the body is gray to brown. There are 20 to 30 dark gray, rhombic spots along the back. At the back of the head there is a dark angular spot. The ventral side is yellowish to light gray in color. As is typical for vipers, the venom apparatus consists of venom glands located on the side of the skull (specialized salivary glands ) and movable fangs located in the anterior upper jaw (solenoglyph tooth position). In Causus rhombeatus , the poison glands are noticeably large and reach far back on the sides of the neck.
Pholidosis
The pholidosis (scaling) shows the following characteristics:
- On the top of the head, snake-like shields, large and juxtaposed,
- the canthus is dull,
- 6 to 7 upper lip shields ( supralabials ),
- 8 to 11, rarely up to 13 lower lip shields ( sublabials ),
- 17 to 21 rows of smooth to weakly keeled trunk scales ( Scuta dorsalia ),
- 134 to 155 abdominal shields ( scuta ventralia ),
- 20 to 33 under tail shields ( Scuta subcaudalia ) and
- 1 undivided anal shield ( scutum anale ).
Systematics
The first description of Causus rhombeatus took place in 1823 by the German zoologist Martin Hinrich Lichtenstein under the name Sepedon rhombeata . Currently (as of 2018) no subspecies are listed.
distribution
The distribution area in sub-Saharan Africa includes areas in Angola , South Africa , Natal , Swaziland , Democratic Republic of the Congo , Sudan , Ethiopia , Somalia , Botswana , Zambia , Zimbabwe , Mozambique , Tanzania , Rwanda , Burundi , Uganda , Malawi , Kenya , Congo , Cameroon , Central African Republic , Equatorial Guinea , Nigeria and Namibia . Biotopes are settled at an altitude of up to 2200 meters. In savannahs , Causus rhombeatus is mostly found in habitats close to water. Occasionally it is found at the edges of forests or in clearings.
Way of life
Causus rhombeatus leads a predominantly nocturnal and ground-dwelling way of life. During the day, empty termite mounds, piles of stones, rotting leaves or holes in the ground are sought out as hiding places. Often, however, she can also be observed sunbathing in the morning or in the afternoon. Especially at night the snake searches for food on the ground and sometimes in the branches of low bushes. The range of prey includes frogs and small lizards that are detected by the sense of smell. Frogs and toads are often swallowed alive without the venom immobilizing them beforehand.
When provoked, the front body is flattened and puffing sounds can be emitted. The front body is lifted and put in loops. The species is considered to be less aggressive and relatively lazy to bite.
Reproduction
The propagation is done by oviparity so oviparous. After mating, females can store the male semen for up to five months and thus carry out fertilization at later times. A clutch comprises 12 to 26 eggs. Hatching occurs three to four months after oviposition. The young snakes measure 14 to 16 cm when they hatch and feed on tadpoles and young frogs shortly after metamorphosis . In Causus rhombeatus an egg laying can take place several times a year.
Snake venom
In the case of a poison bite, 20 to 30 mg (dry weight) of poison secretions can be released. Little is known about the composition and pharmacology of the toxin mixture. It has a predominantly hemotoxic effect and has toxins which inactivate antithrombin III . Notable individual substances are, for example, kallikrein-Cau1 and neurotoxin-like protein 1.
Bite accidents in humans are mostly mild, severe symptoms are rarely observed. Possible effects can include local pain, swelling , lymphadenopathy, and hyperthermia . Therapy is symptomatic. An antivenin is not available.
Individual evidence
- ↑ a b Causus rhombeatus in The Reptile Database (accessed on July 16, 2018)
- ↑ a b c University of Adelaide, Clinical Toxinology Resources: Causus rhombeatus (accessed July 16, 2018)
- ↑ UniProt: Kallikrein-Cau1 (accessed on July 16, 2018)
- ↑ UniProt: Neurotoxin-like protein 1 (accessed on July 16, 2018)
literature
- Ludwig Trutnau: Snakes in the Terrarium Vol. 2: Poisonous snakes . Verlag Ulmer, Stuttgart 1998, ISBN 3-800-1705-23 .
