Lachesis (genus)

Lachesis, also known as bushmasters,[2] is a genus of venomous pit vipers found in forested areas of Central and South America. The generic name refers to one of the Three Fates, Lachesis, in Greek mythology who determined the length of the thread of life.[2][3] Four species are currently recognized.[4]

Lachesis
South American bushmaster, L. muta
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotalinae
Genus: Lachesis
Daudin, 1803
Synonyms

Description

Adults vary in length from 2 to 3 m (6.6 to 9.8 ft), although some may grow to as much as 4 m (13 ft), making it the longest venomous snake in the Western Hemisphere. Bushmasters are the longest type of viper in the world. L. muta is possibly the largest of the three species currently recognized, although more scant information suggest L. stenophrys broadly overlaps in size and may average at a similar size, while L. melanocephala is slightly smaller than the other two species.[5][6][7] Although they are not the heaviest vipers, being surpassed in mass by the Gaboon viper and the Eastern diamondback rattlesnake, large adults still can weigh up to 3 to 7 kg (6.6 to 15.4 lb).[8] Bushmasters are sexually dimorphic in size, with males reaching larger sizes than females.[9] The bushmaster's tail ends with a horny spine which sometimes vibrates when disturbed like rattlesnakes.[10] This has led to some calling it 'the mute rattlesnake'.

Geographic range

Found in central and South America, including the island of Trinidad.[1][11]

Reproduction

Bushmasters lay eggs: about a dozen in an average clutch. The female reportedly remains with her eggs during incubation and may aggressively defend the nest if approached. The hatchlings average 30 cm (12 in) in length and are more colorful than the adults. Lachesis is thought to be unique among New World pit vipers by laying eggs rather than giving birth to live young, although some evidence suggests that the species Bothrocophias colombianus found in Colombia may do the same.[2]

Venom

This snake is capable of multiple-bite strikes and the injection of large amounts of venom. Even the bite of a juvenile specimen can be fatal. However, this snake is rarely encountered so snakebite incidents are not common. The venom of Lachesis has several activities, such as the activation of plasminogen, leading to increased permeability of blood vessels, causing edema and lowering of blood pressure, it also has coagulant activity where thrombin-like enzymes act on fibrinogen, forming small clots that settle in organs such as lungs and kidneys, obstructing capillary blood flow, hemorrhagic activity is caused by metalloproteinases, which damage capillary walls, both coagulant and hemorrhagic activities act in combination triggering local and systemic hemorrhagic disorders, proteolytic activity is due to direct action of proteases (thrombin for example), metalloproteases, and important myotoxic and cytolytic factors, myotoxic action occurs due to the action of phospholipase, generating an inflammatory infiltrate composed of polymorphonuclear leukocytes and macrophages around necrotic cells. phospholipases can induce necrosis of skeletal muscle fibers, while the defibrinating action results in blood incoagolability, the venom also has a kininogen-like action, it causes the body to release substances such as bradykinin and kallikrein inducing hypotension, bradykinin-enhancing peptides interfere with the bradykinin metabolism causing it to last longer in the blood, leading to lasting hypotension, the venom also has a neurotoxic action, isolated from basic phospholipase, is capable of inducing irreversible blockage of neuromuscular transmission in vitro at as low concentrations as 1 mg / ml.[12]

Species
Species[4] Taxon author[4] Subsp.*[4] Common name[2] Geographic range[1]
L. acrochorda (Garcia, 1896) 0 Chocoan bushmaster Panama, Colombia, and Ecuador.
L. melanocephala Solórzano & Cerdas, 1986 0 Black-headed bushmaster Costa Rica: Pacific versant of southeastern Puntarenas province from near sea level to about 1500 m.
L. mutaT (Linnaeus, 1766) 1 South American bushmaster South America in the equatorial forests east of the Andes: Colombia, eastern Ecuador, Peru, northern Bolivia, eastern and southern Venezuela, Guyana, Surinam, French Guiana and much of northern Brazil. It also occurs on the island of Trinidad.[11]
L. stenophrys Cope, 1875 0 Central American bushmaster Central America in the Atlantic lowlands of southern Nicaragua, Costa Rica and Panama, as well as the Pacific lowlands of central and eastern Panama. In South America it occurs in the Pacific lowlands of Colombia and northwestern Ecuador, the Caribbean coast of northwestern Colombia and inland along the Magdalena and Cauca river valleys.

*) Not including the nominate subspecies.
T) Type species.

Taxonomy

Campbell and Lamar (2004) also recognize a fourth species, L. acrochorda (García, 1896), referring to it as the Chochoan bushmaster. It is found in western Panama and northwestern Colombia and Ecuador.[2] Its evolutionary relationships are not certain, but Lachesis acrochorda is thought to be closer to the South American bushmaster L. muta than to the two Central American species L. stenophrys and L. melanocephala. The snake is known to be one of the deadliest snakes in the world.

Cultural depictions

The bushmaster snake is the antagonist in the tenth show of the old time radio show Escape. The show's title was "A Shipment of Mute Fate", and starred Jack Webb and Raymond Lawrence. It was broadcast on 15 October 1947. The story was also adapted for Suspense starring Jack Kelly, broadcast on January 6, 1957. Jack T. Colton killed a bushmaster in the film Romancing the Stone from 1984 when seeking shelter in a crashed plane.

The following weapons and military vehicles are named after this viper:

References
  1. McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
  2. Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. 2 volumes. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
  3. Beolens B, Watkins M, Grayson M. 2011. The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Lachesis, p. 149).
  4. "Lachesis". Integrated Taxonomic Information System. Retrieved 25 October 2006.
  5. Boyer, D. M., Mitchell, L. A., & Murphy, J. B. (1989). Reproduction and husbandry of the bushmaster Lachesis m. muta at the Dallas Zoo. International Zoo Yearbook, 28(1), 190-194.
  6. Corrales, G., Meidinger, R., Chacon, D., & Gomez, A. (2014). Reproduction in captivity of the Central American bushmaster (Lachesis stenophrys, Serpentes: Viperidae), in Costa Rica. Cuadernos de Herpetología, 28(2).
  7. Ripa, D. (2001). The Bushmasters (Genus Lachesis Daudin 1803); Morphology, Evolution, and Behavior. Wilmington, NC: Ecologica.
  8. Zamudio, K. R., & Greene, H. W. (1997). Phylogeography of the bushmaster (Lachesis muta: Viperidae): implications for neotropical biogeography, systematics, and conservation. Biological Journal of the Linnean Society, 62(3), 421-442.
  9. Boos, H. E. (2001). The snakes of Trinidad and Tobago (No. 31). Texas A&M University Press.
  10. Allf, B. C., Durst, P. A., & Pfennig, D. W. (2016). Behavioral plasticity and the origins of novelty: the evolution of the rattlesnake rattle. The American Naturalist, 188(4), 475-483.
  11. List of Snakes of Trinidad and Tobago Archived 2006-08-08 at the Wayback Machine at Republic of Trinidad and Tobago Biodiversity Clearing House Archived 2012-12-21 at Archive.today. Accessed 25 October 2006.
  12. http://www.lachesisbrasil.com.br/download/BulChicagoHerpSoc_Vol42Num7pp105-115%282007%29.pdf

Further reading
  • Eatherley, Dan. Bushmaster: Raymond Ditmars and the Hunt for the World's Largest Viper. 2015 (Arcade: New York City)
  • Mehrtens, J.M. Living Snakes of the World in Color. New York: Sterling Publishers. 1987. 480 pp. ISBN 0-8069-6460-X.
  • O'Shea, Mark. Venomous Snakes of the World. Princeton University Press. 2005. 160 pp. ISBN 0-691-12436-1.
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