Common lance viper
|Common lance viper|
Common Lance Viper ( Bothrops atrox )
|( Linnaeus , 1758)|
Bothrops atrox reaches a total length between 120 and 180 cm, rarely more than 200 cm. The head is angular, elongated, triangular in shape when viewed from above and clearly set off from the neck. The eye has a pupil that is vertically slit when exposed to light. The body has a brown, yellow-brown or olive basic color that becomes lighter towards the sides. The body is surrounded by silvery horizontal stripes at intervals of 2 to 6 cm. The sides of the body are drawn with 20 to 30 black triangular spots (edge and center lightened). There is a light stripe between the eye and the back of the head. The top of the head is colored brown. The ventral side has a whitish to yellowish color and is darkly spotted. 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).
The two species Bothrops atrox and Bothrops asper can vary in their appearance and can be confused with one another. Furthermore, Bothrops marajoensis cannot be differentiated morphologically from Bothrops atrox .
The pholidosis (scaling) shows the following characteristics:
- 6 to 9 upper lip shields ( supralabials ),
- 7 to 13 lower lip shields ( sublabials ),
- 23 to 29 rows of strongly keeled trunk scales ( Scuta dorsalia ),
- 169 to 212 abdominal shields ( scuta ventralia ) and
- 47 to 86 divided under- tail shields ( Scuta subcaudalia ).
It was first described by the Swedish zoologist Carl von Linné in 1758 under the name Coluber atrox . The systematics of the genus Bothrops is the subject of research. On the basis of molecular biological studies, among other things , Fenwick et al. (2009) and Wallach et al. (2014) suggested splitting the genus. The taxonomic status of Bothrops atrox is also unclear. Possibly other species of the genus Bothrops atrox can be assigned. This needs to be clarified in particular in the case of the following species (status 2018): Bothrops colombiensis , Bothrops leucurus , Bothrops marajoensis , Bothrops moojeni and Bothrops pradoi . Bothrops isabelae is now largely regarded as a synonym for Bothrops atrox , but is still sometimes listed as a separate species. Subspecies are not listed for Bothrops atrox .
The distribution area in South America includes regions in Guyana , Suriname , French Guyana , Venezuela , Brazil , Colombia , Ecuador , Peru , Bolivia and the island of Trinidad . The populated biotopes are represented by tropical rainforests , moderately montane moist forests or gallery forests in savannah areas . Bothrops atrox is regularly found on agricultural areas (e.g. plantations with bananas, sugar cane, coffee or cocoa) and in the vicinity of human settlements, mostly near water.
Way of life
Bothrops atrox leads a soil-dwelling and largely nocturnal way of life. During the day it hides between roots, under fallen leaves or the like, with the body curled up like a plate. The hiding places are especially abandoned after heavy rains. The snake is occasionally found climbing, especially when the habitat is flooded. The range of prey includes small mammals, lizards, frogs, small birds and other snakes.
If disturbed, she defends herself with poison bites. The front body is thrown forward like a lance, so that the range of the snake is large in the event of a bite. The propagation is done by ovoviviparity , so egg-viviparous. A litter can contain between 10 and over 20 juvenile snakes. These measure around 25 cm at birth and feed on small vertebrates.
Life expectancy in captivity is 8.5 years. Trutnau reports of individuals who lived to be over 20 years of age in captivity.
Bothrops atrox , along with some closely related species ( Bothrops asper , Bothrops jararaca ), is responsible for most of the life-threatening and fatal poisonings from snake bites in Latin America . This is justified by a large distribution area, the proximity to humans, a potent poison and the relatively high amount of poison. When approaching, it relies on its camouflage and may therefore be overlooked. In distress, she does not hesitate to defend herself with poisonous bites. The mortality rate is low in the case of adequate medical care.
The yield of a poison bite is 70 to 160 mg, sometimes up to 300 mg of poison secretion (dry weight). The poison of Bothrops atrox , like that of most pit vipers, has a very complex composition and contains prothrombin activators , cytotoxins , hemorrhagins ( blood vessel-damaging zinc metalloproteases ) and systemically active myotoxins as pharmacologically active components .
Noteworthy individual substances are:
- Batroxobin : Snake Venom Thrombin- like enzyme, influences hemostasis by splitting fibrinogen into fibrin .
- Atroxlysine-1: Zinc metalloprotease, interacts with numerous substrates , including fibrin , fibrinogen , collagens and integrins ; causes an inhibition of platelet aggregation and tissue damage, including blood vessels (hemorrhagic activity, bleeding).
A poison bite must be viewed as potentially life threatening. Possible non-specific general symptoms are headache, abdominal pain, cramps and dizziness. Key symptoms of poisoning after poison bite by Bothrops atrox are local swelling , blistering , necrosis (possibly necessary amputations ) and bleeding . When the coagulation factors are used up, disseminated intravascular coagulopathy can occur. Secondary damage to the kidneys can occur. Toxins and blood loss can cause shock and circulatory failure . Various antivenins , such as 'Polyvalent Antivenom' (Instituto Clodomiro Picado, Costa Rica) or 'Soro antibotropico-laquetico' (Instituto Butantan, Brazil), are available for therapy.
The species has a relatively large range and is common there. The common lance viper is not listed by the IUCN .
- Bothrops marajoensis in The Reptile Database (accessed July 3, 2018)
- Bothrops atrox in The Reptile Database (accessed July 3, 2018)
- University of Adelaide, Clinical Toxinology Resources: Bothrops atrox (accessed July 3, 2018)
- AnAge, The Animal Aging and Longevity Database: Bothrops atrox (accessed July 3, 2018)
- UniProt: Thrombin-like enzyme batroxobin (accessed July 3, 2018)
- UniProt: Snake venom metalloproteinase atroxlysin-1 (accessed July 3, 2018)
- Animal Diversity Web: Bothrops atrox (accessed July 3, 2018)
- Ludwig Trutnau: Snakes in the Terrarium Vol. 2: Poisonous snakes . Verlag Ulmer, Stuttgart 1998, ISBN 3-800-1705-23 .