Lachesis (genus)
Lachesis muta muta
Bushmaster ( Lachesis ) are a snake genus of the subfamily of pit vipers. The genus occurs with four species in Central America and northern South America. All species are bound to forest and soil alive. The species are poisonous, but bite accidents are rare due to the low aggressiveness and retracted life of the animals. The bite often does not lead to severe poisoning in humans, but usually death. The genus is named after a Greek goddess of fate ( Lachesis ).
- 6.1 Notes and references
- 6.2 Literature
- 6.3 External links
Features
Physique
All Bushmaster are very large, medium- slim pit vipers. The body is usually compressed laterally. The head is large and rather elongated, but not very clearly set off from the neck, the eyes are relatively small. The muzzle is usually broadly rounded, the tip of the snout is not extended. The canthus is rounded. The tail is not prehensile. All species have regularly total lengths of over 1.9 m, secured maximum dimensions are between 2.32 m and 3.0 m in total length. Bushmaster are thus the largest vipers in the world and the largest venomous snakes in America.
Squamation
The rostral scale is usually approximately triangular and as wide or wider than tall. There are three Praeocularia, of which the upper one is significantly larger than the other. The Supraocularia are large and elongated and separated by 10-15 round Intersupraocularia. There are 2-3 Canthalia on each side. The top of the head is covered with small, mostly keeled scales. The number of supralabials is 7 to 11, the number of Infralabialia 11 to 17 The number of ventral scales ( Ventralschilde ) varies 191-236, the number of shared Subcaudalia between 31 and 56, the rear Subcaudalia are thorny in 4-5 rows shed divided. The number of dorsal scale rows in the middle of the body varies 21 to 27 The scales at the center back have significantly raised, rounded keels.
Coloring
Bushmaster are color very appealing. The ground color of the upper side is variable pink - brown, orange - brown, reddish brown or yellowish. Show on the back of the animals on this basis a number of very distinctive large, dark brown or black, more or less rhombic spots. These are transverse to the longitudinal axis of the animals and run on the lower flanks more or less pointed out. The spots often show bright centers or are more or less interrupted sharply. The skull is one color depending on how the rest of the body color, mottled with dark or completely black. The sides of the head show a broad dark Postokularstreifen, which extends from the posterior edge past the muzzle angle.
Distribution and habitat
Bushmaster are common in Central America and northern South America. The range extends from the central Nicaragua south to Bolivia in the middle and to the east of Brazil. Two of the four species have relatively small areas in Central America; the area L. muta includes large parts of northern South America. Bushmaster are residents of the original tropical rain forest at altitudes of about 1600 m.
System
Campbell & Lamar recognize four types:
- Lachesis acrochorda ( García 1896); Eastern Panama, West Columbia, Northwest Ecuador.
- Lachesis melanocephala Solorzano & Cerdas, 1986; southeastern Costa Rica and adjacent areas in western Panama.
- Lachesis muta (Linnaeus 1766 ): Amazon basin, Guyanaschild (. Subspecies L. m muta), Southeast Brazilian coastal rain forest ( subspecies L. m rhombeata. ).
- Lachesis stenophrys Cope 1875: Nicaragua, Costa Rica, Panama.
Until recent years, L. muta was with four subspecies, the only species of the genus Lachesis. Due to a molecular genetic analysis in 1997 two of the subspecies (L. melanocephala and L. stenophrys ) were separated as a distinct species from L. muta. The fourth type was separated from Cambell & Lamar L. acrochorda 2004.
Also, a molecular genetic analysis involving 2 of the 4 species has confirmed the monophyly of the genus Lachesis inside the pit vipers, a molecular genetic analysis involving all four species is not yet available so far.
Lifestyle, diet, and reproduction
All species of the genus are almost exclusively nocturnal and ground alive. The day is spent in Säugerbauten, under fallen trees and other similar places. The animals often stay for several days or weeks in the same hiding place. Bushmaster are lurking predators that often linger for days in the same place. The food apparently consists almost exclusively of small mammals, especially mice -like, but also marsupials and squirrels.
In contrast to all other American pit vipers are bushmaster lays eggs ( oviparous ). Eggs are laid in buildings occupied as a day hiding caves that females encircle the eggs until hatching of the young snakes. The scrim include 6-11, up to a maximum of 20 eggs. The time until the slip is different specified depending on the author with 60 to 90 days.
Poison
Bushmaster are obviously neither aggressive nor particularly looking for them on the human settlement area. Therefore bite accidents, compared with occurring in the same habitat types of the American Terciopelos rattlesnakes rarely. So did bush masters of bites after a survey in Colombia only 2% of all poisoning by snakes. Even in a specialized center in Manaus, Brazil, are dealt with in the annual 200 bite accidents, a total of only 10 bites were documented by L. muta over several years. Cited multiple in the literature to the Government of Brazil, the L. muta 15,000 bite accidents attributed nationwide for a period of 4.5 years, David Warell therefore considers implausible.
The venom is not very toxic, and the amount of poison is in spite of the size of the animals generally much smaller than the much smaller individuals of the American Terciopelos. The typical symptoms of poisoning are described relatively uniform: initial nausea, severe intestinal cramps, recurrent vomiting, watery diarrhea and profuse sweating. In addition, swelling and rare bleeding disorders or necrosis may occur. Extreme are the contradictory information on the incidence of death. While, according to a retrospective study in Costa Rica three out of four people bitten died are from the other countries in the distribution area, although single made famous in part severe poisoning, but only a secure death in Colombia.