Earth vipers
| Earth vipers | ||||||||||||
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Atractaspis engaddensis |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Atractaspididae | ||||||||||||
| Günther , 1858 |
The terrestrial vipers (Atractaspididae) represent a family of snakes (Serpentes). They were scientifically described for the first time in 1858 by the German zoologist Albert Günther .
features
The terrestrial vipers are relatively small snakes that reach body lengths between about 30 and 100 cm. The body is generally more or less cylindrical. Their heads are mostly cylindrical, small and pointed. It hardly or not at all separates itself from the rest of the body. The top of the head in particular has large scaled shields, and the side shields are also large. A rein shield ( Loreale ) is missing. The eyes are small and the pupils are round or oval. Around the middle of the earth vipers are around 15 rows of back scales. The scales are smooth. The tip of the tail is often thorny or blunt. The body coloring and drawing is very different and can be simply monochrome and without a pattern or multi-colored and with a wide variety of patterns.
Dentition and venom apparatus
The special structure of the dentition and the poison apparatus is very variable within the terrestrial viper family. All terrestrial vipers have salivary glands, so-called Duvernoy glands, which have been transformed into poison glands, which in some species, especially atractaspis , clearly reach into the front body. The venom glands are almost always connected to fangs . Earth vipers have the longest fangs of the snakes in relation to the length of their head. They lie in a horizontal position on the upper jaw bone ( maxillary ), which is connected to the frontal and prefrontal bones in such a way that the poisonous teeth are only slightly mobile and can be stuck out of the side of the mouth, they then point backwards. Coupling it with a lancing movement facilitates the lateral bite or puncture and the injection of the snake venom. The mouth can remain more or less closed. There are hardly any more teeth, Atractaspis has lost all other teeth apart from the greatly reduced lower jaw teeth and the canines, which are in the front area of the upper jaw. The species of the genera Amblyodipsas , Chilorhinophis , Macrelaps and Xenocalamus have short upper jaws with a pair of fangs under the eyes and 3 to 5 normal teeth, Aparallactus mostly also has enlarged fangs under the eyes, but in the species Aparallactus modestus , for example, they are completely absent. As a rule, the poison is passed through a groove in the fangs into the bite wound. The position of the poison fangs makes it almost impossible to grab earth vipers behind the head without suffering a bite.
Snake venom
The terrestrial vipers usually produce a relatively weak snake venom . Snake catchers in particular are regularly bitten by snakes of this family. This is due to the peculiar location of the fangs. Poison bites often occur when you pick up a ground viper that has not been identified as such and want to hold it behind your head to more precisely identify the species. Despite the relative frequency of the bites, only three species of Atractaspididae have died so far , including Atractaspis irregularis and the Arabian ground viper ( Atractaspis microlepidota ) as one of the most poisonous, which in Somalia is nicknamed the "Seven Steps", which is on the Notion based that one bite should kill this snake quickly. However, in one documented case, death occurred within just under six hours, which is probably already quite quick. The bite of Mueller's earth viper ( Micrelaps muelleri ) is also dangerous . In almost all species, a poison bite is extremely painful, luckily it is rarely drastic.
Toxins and poisonous effects
The poison of the earth vipers is structured very differently. Mostly it contains more or less low neurotoxic , occasionally cytotoxic properties. Sarafotoxins are characteristic of many species of the family , which are unique among snakes and attack the heart as cardiotoxins by negatively influencing the blood flow in the coronary arteries by narrowing these vessels and thus leading to a heart attack. Mytoxins, which attack muscle tissue, the heart muscle and other muscles , have been found in the poison of some earth vipers . After a bite, depending on the type, only local symptoms such as pain and swelling of the bitten limb, swelling of the lymph nodes and also necrosis may occur or systemic symptoms such as pain when moving the tongue and eyelids as well as when swallowing, paralysis, nausea and vomiting, Diarrhea, headache and fever occur. Any coagulants that may occur can also lead to a disruption of blood clotting . In the case of dangerous species, death can result from a circulatory collapse , cardiac arrest, or respiratory paralysis.
therapy
After a bite, all constricting objects (wristwatches, rings, etc.) should first be removed because of the often severe swelling. If possible, an emergency doctor must be called and prone transport must be carried out, in any case one should try to remain calm. The bite wound is cleaned locally with antiseptic and targeted antibiotics are given. Surgical intervention is only necessary in the case of necrosis or an abscess and may only be performed if the coagulation values are normal. If necessary, vaccination or booster protection against tetanus should be carried out. Upon the occurrence of hypotension (low blood pressure) and a shock are corticosteroids and antihistamines to be administered to counteract the dilation of blood vessels. Adrenaline is to be provided in case of emergency. Patients are to be observed in hospital for at least 24 hours, especially with regard to cardiac activity, symptoms of paralysis and fibrinogen levels .
Way of life
Earth vipers lead a very hidden way of life, they live as burrowing snakes underground, often probably in the corridors that dig their prey. In doing so, they bore their pointed heads first through the substrate and, if necessary, repel themselves with the spike at the tip of the tail. The smooth scales and the evenly cylindrical shape of the entire body prevent heavy braking and getting caught in bumps. It rarely happens, mostly at night, that terrestrial vipers can be found on the surface. Typical of most Earth vipers is their warning posture, in which the snout is placed flat on the ground and the neck is pressed upwards in an arched manner. Due to the way of life, there are hardly any encounters with people. However, heavy rainfall can drive the snakes closer to the surface, which can make walking barefoot potentially life-threatening. Another consequence of the hidden way of life is the fact that relatively little scientific data is available about the terrestrial viper family.
Reproduction
The reproductive behavior of terrestrial vipers is also still relatively unexplored. The family is almost always egg-laying ( oviparia ). The millipede Aparallactus jacksoni gives birth to live eggs ( ovoviviparia ) and gives birth to live young. Another species believed to be egg-bearing is Amblyodipsas concolor . In other species and genera there is uncertainty about the mode of reproduction. As a rule, little information is available about the size of the clutch and litter; most oviparous species assume a clutch size of between three and ten eggs.
nutrition
The prey spectrum of the terrestrial vipers is quite large. It ranges from frogs and burrowing amphibians such as caecilians to reptiles, especially legless lizards , and in some cases other snakes , to small mammals such as burrowing rodents . Most species combine several prey animals. The species of the millipede ( Aparallactus ) are very specialized and only prey on millipedes . The structure of the poison apparatus and the dentition is an adaptation to the underground way of life of the terrestrial vipers. They can hardly open their mouths in the narrow corridors, prey animals are stabbed from the side with a poisonous tooth and the poison is injected. If it is immobile or dead, it is swallowed in one piece, as is typical of a snake.
Occurrence
The distribution area of the terrestrial vipers is limited to the whole of Africa (with the exception of certain regions) and the southwest Arab region as well as Israel in the Middle East . It is noteworthy that in most countries only one or two species can be found, although nine species of terrestrial vipers can be found in Cameroon and eight in the Congo . The habitats of these snakes are very diverse and range from sand, stone, scree and semi-deserts to steppes and savannas to sparse forests, coastal forests and rainforests.
Systematics
The terrestrial vipers are difficult to classify taxonomically , until a few years ago the members of the family were literally pushed back and forth between vipers and snakes , sometimes even classified as poisonous snakes . According to recent studies, they form, together with some subfamilies of the paraphyletic snakes, the family Lamprophiidae , whose sister group are the poisonous snakes . The following 12 genera are included in the terrestrial viper family :
- Amblyodipsas
- Aparallactus
- Atractaspis
- Brachyophis
- Chilorhinophis
- Elapotinus
- Hypoptophis
- Macrelaps
- Micrelaps
- Poecilopholis
- Polemon
- Xenocalamus
swell
Individual evidence
- ↑ Ulrich Gruber: The snakes of Europe and around the Mediterranean , Franckh-Kosmos-Verlag, 1989. ISBN 3-440-05753-4 .
- ↑ GEO thematic dictionary: Animals and plants: creatures, species, habitats ; Part 1 / Vol. 33. 2008. ISBN 978-3-7653-9463-8 .
- ^ Integrated Taxonomic Information System: Atractaspididae
literature
- Mark O'Shea: Venomous snakes. All species in the world in their habitats. Franckh-Kosmos Verlag, Stuttgart 2006, ISBN 3-440-10619-5 .
- Chris Mattison: Encyclopedia of Snakes. blv Verlag, 2007, ISBN 978-3-8354-0360-4 .