Jararaca Lance Viper
| Jararaca Lance Viper | ||||||||||||
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Jararaca Lance Viper |
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| Bothrops jararaca | ||||||||||||
| ( Wied-Neuwied , 1824) |
The Jararaca Pitviper or short Jararaca ( Bothrops jararaca , Syn. : Bothropoides jararaca ) is a species of snake in the subfamily of pit vipers . It inhabits the southeast of Brazil , the extreme east of Paraguay and the northeast of Argentina . As with most species of the genus Bothrops, the diet consists of a wide range of small vertebrates, young animals also eat invertebrates . Like all American lanceolers, the species is poisonous and one of the most medically relevant venomous snakes within its range, but deaths are rare.
features
The Jararaca lance viper is a long, slender lance viper, the broad head, as with all species of the genus, is clearly set off from the neck. The species becomes a maximum of 1.6 m long, but usually remains significantly smaller. Females grow larger and heavier than males. As part of a study in southeastern Brazil, captured males reached a head-trunk length of a maximum of about 87 cm and a weight of about 152 g, the corresponding maximum values of females were about 103 cm and about 240 g. Eight females from the state of São Paulo , who were already pregnant at least once, were sometimes even larger, they had head-to-torso lengths between 89 and 109 cm and weighed 243-414 g.
Scaling
The species shows five to twelve weakly keeled supraocularia . The number of supralabials is seven to nine (usually eight), the number of infralabials nine to 13, usually ten to twelve. The number of abdominal scales ( ventral shields ) varies between 170 and 216, the number of subcaudalia between 51 and 71 and the number of dorsal rows of scales in the middle of the body between 20 and 27, usually 23 to 25.
coloring
The basic color of the upper side is very variable reddish, brown, chestnut brown, gray, yellow or olive green, usually the middle of the trunk is slightly lightened. The upper side of the torso shows light-edged, dark brown, trapezoidal or nearly triangular drawings on both sides of the back, the broad base, which is open at the bottom, points towards the stomach. The points of the drawings can meet in the middle of the spine, so that the spine shows a very conspicuous X-mark, or they can be partially or completely offset from one another; often all three variants can be seen on one individual. The individual drawing elements can be lengthened in a very variable manner, merged with one another or only formed in fragments. In some individuals, the center of the back is completely undrawn and the drawing is reduced to alternating, paired stripes on the sides. The spaces between the drawing elements are usually irregularly spotted, especially on the back third of the body. The drawing on the tail becomes increasingly narrow and mostly consists only of light gray lines on a dark background.
The belly side is pale green to yellowish white and shows irregular fine or larger gray spots, sometimes the belly is also a solid gray. In young animals the tail end is white.
The back of the head often shows diffuse, dark drawings, but these can also be missing or barely visible due to an overall darker basic color. A noticeable dark brown stripe (postocular stripe) extends from the eye to the corner of the mouth and usually includes the three posterior upper lip shields ( supralabials ). This stripe is limited at the top by a pale area. The area of the canthus and the supralabials are otherwise mostly undrawn, but some individuals show a dark spot between the third and fourth supralabials. The eyes have vertical pupils , the iris is golden to greenish gold. The tongue is black.
distribution and habitat
The Jararaca lance viper inhabits the southeast of Brazil, the extreme east of Paraguay and the northeast of Argentina . It inhabits tropical deciduous forests and savannahs there , apparently preferring to inhabit open habitats that are also used for agriculture with adjacent higher vegetation. The species is also found in large cities such as Rio de Janeiro and São Paulo .
Systematics
No subspecies have been described for the Jararaca lance viper. A molecular genetic investigation that includes all species or taxa of the genus Bothrops is not yet available. In the most comprehensive molecular genetic work to date, which considered 28 species or forms of the genus, the island lance viper ( Bothrops insularis ) was identified as the closest relative of the Jararaca lance viper .
Lifestyle and diet
Like almost all species of the genus, the species is largely nocturnal. It lives mostly on the ground, but also often climbs into low bushes. Young animals attract prey by movements with the light tail end and feed primarily on frogs, small rodents , centipedes and birds are less common . Adult animals mainly eat rodents, but also lizards , frogs and birds.
In a study in Southeastern Brazil in the stomachs of adult were Jaracara-Terciopelos as the main prey (9 of 16 prey) Mäuseartige as belonging to the genus of neotropical water rats belonging Nectomys squamipes and naturalized brown rat found less frequently young and adult Common guinea pig , Actual echimyidae the genera Echimys and Proechimys , the New World mouse species Necromys lasiurus , the rice rat and the naturalized house mouse . A Japanese quail ( Coturnix japonica ), probably kept as a pet, and a Thoropa miliaris belonging to the southern frogs were also found.
In young animals, mainly (9 of 17 prey animals) tree frogs of various species and the southern frog Physalaemus cuvieri were found in the study, and more rarely young mice such as the rice rat and house mouse. Two snakes had to be the hemidactylus belonging Hemidactylus mabouia eaten, one had a nestling songbirds and another two centipedes of the genus Otostigma captured.
Reproduction
Young animals are born in southeastern Brazil between January and mid-April, i.e. around the second half of the rainy season. Accordingly, pairings will probably take place from April to June. Like all species of the genus, the animals give birth to their young alive and are therefore ovoviviparous . The number of young snakes identified so far per litter is a minimum of 3 and a maximum of 34; in southeastern Brazil eight females gave birth to 5–16 young animals. Newly born young snakes in the state of São Paulo had head-trunk lengths of 19.0–27.5 cm, an average of 25 cm and weighed 4.5–14.0 g, with an average of 9.4 g (males) and 10.6 g (female). Presumably the young are sexually mature after three to four years; Males then have a head-trunk length of about 65 cm, females are then about 75 cm long. Information on the average and maximum ages of individuals living freely or in captivity is unknown.
Poison
The toxin mixtures of pit vipers are by far komplexesten natural poisons. They contain a mixture of enzymes , low molecular weight polypeptides , metal ions and other components whose function has so far hardly been understood. The effects of these poisons are correspondingly diverse. The venom of the Jararaca lance viper causes a whole range of symptoms, a distinction being made between local and the whole body ( systemic ) symptoms.
Local effects
The poison contains tissue-destroying enzymes , especially phospholipase A 2 and highly protein-degrading metalloproteinases . Typical local symptoms are primarily severe pain, redness, and swelling that quickly spread to the entire bitten limb and the adjacent trunk, as well as small or large blisters that contain clear or blood- serous fluid. Often necroses develop , especially of the muscle tissue. If treatment is not initiated or initiated too late, the affected limbs must occasionally be amputated because of the necrosis. Further permanent damage is functional impairment or loss due to muscle wasting ( atrophy ), permanent muscle shortening and paralysis of peripheral nerves.
Systemic effects
The poison has a hemolytic effect (destroys red blood cells) and, through metalloproteinases, has a hemorrhagic effect (destroys blood vessels). The main hemorrhagin in the venom of the species is jararhagin , a zinc- containing metalloproteinase. The poison causes a change in the blood coagulation precursor fibrinogen through thrombin-like enzymes (TLEs) and thereby a pathological activation of blood coagulation . This leads to the rapid consumption of the coagulation factors via further steps and therefore has an anticoagulant effect . As a result, normal blood clotting is no longer possible. The syndrome is known as Disseminated Intravascular Coagulopathy (DIC). The patients bleed from the bite site, from unhealed scars, mosquito bites and oral mucous membranes and internal bleeding occurs. The poison is apparently also directly toxic to the kidneys. Additional complications arise from infections from the bacterial fauna contained in the snake's mucous membranes. Deaths are due to acute kidney failure, cerebral haemorrhage, and sepsis.
Epidemiology
The area of the species is one of the most densely populated areas in South America and the species is relatively common here, so it is by far the most medically relevant snake in southeastern Brazil. However, fatal poisoning is relatively rare; In various studies, the death rate of hospitalized bite victims was between 0 and 1 percent.
Medical use
Peptides from the venom of the Jararaca lance viper formed the basis for the development of the ACE inhibitors against high blood pressure. Sérgio Henrique Ferreira from the University of São Paulo discovered the bradykinin- potentiating factor (BPF) in the venom of the snake in the 1960s , after Mauricio Rocha e Silva isolated bradykinin from it in 1948. In 1974 , in collaboration with John R. Vane in London and scientists at Bristol-Myers Squibb (especially David Cushman, Miguel Ondetti), this resulted in captopril , the lead compound of ACE inhibitors.
The venom of the Jararaca lance viper also contains the enzyme reptilase , which is used in medicine for both diagnostic and therapeutic purposes because of its effect on blood coagulation .
Danger
The species has a relatively large range and is common there; it is therefore not viewed as endangered by Campbell and Lamar. The Jararaca lance viper is not listed by the IUCN .
swell
Individual evidence
- ↑ I. Sazima: Natural History of the Jararaca pitocket, Bothrops jararaca, in southeastern Brazil. In: Campbell, JA & ED Brodie (eds.): Biology of Pitvipers. Selva, Tyler; 1992: p. 202; Values taken from diagram (Fig. 5).
- ↑ I. Sazima: Natural History of the Jararaca pitocket, Bothrops jararaca, in southeastern Brazil. In: Campbell, JA & ED Brodie (eds.): Biology of Pitvipers. Selva, Tyler; 1992: p. 202
- ^ W. Wüster, MG Salomão, JA Quijada-Mascareñas, RS Thorpe and BBBS P: Origin and evolution of the South American pitocket fauna: evidence from mitochondrial DNA sequence analysis. In: GW Schuett, M. Höggren, ME Douglas & HW Greene (eds): Biology of the Vipers. Eagle Mountain Publishing, Eagle Mountain, Utah, 2002: pp. 111-128.
- ↑ a b I. Sazima: Natural History of the Jararaca pitocket, Bothrops jararaca, in southeastern Brazil. In: Campbell, JA & ED Brodie (eds.): Biology of Pitvipers. Selva, Tyler; 1992: pp. 204-205.
- ↑ I. Sazima: Natural History of the Jararaca pitocket, Bothrops jararaca, in southeastern Brazil. In: Campbell, JA & ED Brodie (eds.): Biology of Pitvipers. Selva, Tyler; 1992: p. 203.
- ↑ Smith, Vane The Discovery of Captopril , FASEB J. , Volume 17, 2003, p. 788, Online, pdf .
literature
- Jonathan A. Campbell, William W. Lamar: The Venomous Reptiles of the Western Hemisphere. Comstock; Ithaca, London; 2004: pp. 349, 354, 390-392, ISBN 0-8014-4141-2 .
- I. Sazima: Natural History of the Jararaca pitocket, Bothrops jararaca, in southeastern Brazil. In: Campbell, JA & ED Brodie (editors): Biology of Pitvipers. Selva, Tyler; 1992: pp. 199-216, ISBN 0-9630537-0-1 .
- David A. Warrell: Snakebites in Central and South America: Epidemiology, Clinical Features, and Clinical Management . In: Jonathan A. Campbell, William W. Lamar: The Venomous Reptiles of the Western Hemisphere. Comstock; Ithaca, London. 2004: pp. 709-761, ISBN 0-8014-4141-2 .
