unelevated

Bothrops

Common names: lanceheads, American lanceheads, American lance-headed vipers.

Bothrops is a genus of venomous pitvipers found in Central America, South America. The generic name is derived from the Greek words bothros and ops that mean "pit" and "eye" or "face"; an allusion to the heat-sensitive loreal pit organs. Members of this genus are responsible for more human deaths in the Americas than any other group of venomous snakes. Currently, 32 species are recognized.

Description

These snakes range from small, never growing to more than 50-70 cm, to large at over 200 cm in length. Most are characterized by having a sharp canthus rostralis and an unelevated snout.

The arrangement of the scales on top of the head is extremely variable; the number of intrasupraoculars may be anything from 3 to 14. Usually there are 7-9 supralabials and 9-11 sublabials. There are 21-29 midbody dorsal scales, 139-240 ventral scales and 30-86 subcaudals, which are generally divided.

Geographic range

Found in northeastern Mexico (Tamaulipas) southward through Central and South America to Argentina. Also occurs on the islands of Saint Lucia and Martinique in the Lesser Antilles, as well as on Ilha da Queimada Grande off the coast of Brazil.

Behavior

Most species are nocturnal, although a few that are found at higher altitudes are active during the day. Otherwise they may be seen on cloudy days or during periods of rain. Most are terrestrial, even though all are capable of climbing. One in particular, B. insularis, has a reputation for often being found in trees.

Venom

Members of this genus are responsible for more fatalities in the Americas than any other group of venomous snakes. In this regard, the most important species are B. asper, B. atrox and B. jararaca. Without treatment, the fatality rate is estimated to be about 7%, but with treatment this is reduced to 0.5-3%.

Typical symptoms of bothropic envenomation include immediate burning pain, dizziness, nausea, vomiting, sweating, headache, massive swelling of the bitten extremity, hemorrhagic blebs, local necrosis, bleeding from the nose and gums, ecchymosis, erythemia, hypotension, tachycardia, coagulopathy with hypofibrinogenemia and thrombocytopenia, hematemesis, melena, epistaxis, hematuria, intracerebral hemorrhage and renal failure secondary to hypotension and bilateral cortical necrosis. There is usually some discoloration around the bite site and rashes may develop on the torso or the extremities.

In general, death results from hypotension secondary to hypovolemia, renal failure and intracranial hemorrhage. Common complications include necrosis and renal failure secondary to hypovolemic shock and the toxic effects of the venom.

Species

Species	Taxon author	Subsp.*	Common name	Geographic range
B. alternatus	Duméril, Bibron and Duméril, 1854	0	Urutu	Southeastern Brazil, Paraguay, Uruguay and northern Argentina (in the provinces of Buenos Aires, Catamarca, Córdoba, Corrientes, Chaco, Entre Ríos, Formosa, La Pampa, Misiones, San Luis, Santa Fe, Santiago del Estero and Tucumán.
B. ammodytoides	Leybold, 1873	0	Patagonian lancehead	Argentina in the provinces of Buenos Aires, Catamarca, Córdoba, Chubut, La Pampa, La Rioja, Mendoza, Neuquén, Río Negro, San Juan, San Luis, Santa Cruz and Tucumán.
B. andianus	Amaral, 1923	0	Andean lancehead	Southern mountains of Peru in the departments of Cuzco and Puno at elevations of 1800-3300 m.
B. asper	(Garman, 1884)	0	Terciopelo	Atlantic lowlands of eastern Mexico and Central America, including Guatemala, Belize, Honduras, Nicaragua Costa Rica and Panama. A disjunct population occurs in southeastern Chiapas (Mexico) and southwestern Guatemala. In northern South America in Colombia and Venezuela. Also in Ecuador.
B. atrox	(Linnaeus, 1758)	0	Common lancehead	Tropical lowlands of South America east of the Andes, including southeastern Colombia, southern and eastern Venezuela, Guyana, Surinam, French Guiana, eastern Ecuador, eastern Peru, northern Bolivia and the northern half of Brazil.
B. barnetti	Parker, 1938	0	Barnett's lancehead	Along the Pacific coast of northern Peru at low elevations in arid, tropical scrub.
B. brazili	Hoge, 1954	0	Brazil's lancehead	Equatorial forests of southern Colombia, eastern Peru, eastern Ecuador, southern and eastern Venezuela, Guyana, Surinam, French Guiana, Brazil and northern Bolivia.
B. campbelli	Freire-Lascano, 1991	0	Ecuadorian toadheaded pitviper	Pacific lowlands and slopes from west-central Colombia to Ecuador.
B. caribbaeus	(Garman, 1887)	0	Saint Lucia lancehead	St. Lucia, Lesser Antilles. Apparently restricted to the low elevation periphery of all but the southern third and extreme northern tip of the island.
B. colombianus	Rendahl & Vestergren, 1940	0	Colombian toadheaded pitviper	Pacific versant of Colombia.
B. cotiara	(Gomes, 1913)	0	Cotiara	Araucaria forests of southern Brazil in the states of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. In northeastern Argentina in Misiones Province.
B. erythromelas	Amaral, 1923	0	Caatinga lancehead	Northeastern Brazil in the states of Alagoas, Bahia, Ceará, extreme eastern Maranhão, Minas Gerais, Paraíba, Pernambuco, Piauí, Rio Grande do Norte and Sergipe.
B. fonsecai	Hoge & Belluomini, 1959	0	Fonseca's lancehead	Southeastern Brazil in the states of northeastern São Paulo, southern Rio de Jeneiro and extreme southern Minas Gerais.
B. hyoprorus	Amaral, 1935	0	Amazonian toadheaded pitviper	Northwestern South America in the equatorial forests of southern Colombia, eastern Ecuador, northeastern Peru and western Brazil.
B. iglesiasi	Amaral, 1923	0	Cerrado lancehead	Northeastern Brazil in northern Piaui state.
B. insularis	(Amaral, 1922)	0	Golden lancehead	Queimada Grande Island, Brazil.
B. itapetiningae	(Boulenger, 1907)	0	São Paulo lancehead	Southeastern Brazil in the states of Minas Gerais, Mato Grosso, São Paulo, and on the Paraná Plateau.
B. jararaca	(Wied-Neuwied, 1824)	0	Jararaca	Southern Brazil, northeastern Paraguay and northern Argentina (Misiones).
B. jararacussu	Lacerda, 1884	0	Jararacussu	Eastern Brazil (from Bahia to Santa Catarina), Paraguay, southeastern Bolivia and northeastern Argentina (Misiones province).
B. jonathani	(Harvey, 1994)	0	Cochabamba lancehead	The Altiplano of central Bolivia in the department of Cochabamba, occurring at elevations of 2800-3200 m in dry rocky grassland.
B. lanceolatus^T	(Bonnaterre, 1790)	0	Martinique lancehead	Martinique, Lesser Antilles.
B. leucurus	Wagler, 1824	0	Bahia lancehead	Eastern Brazil along the Atlantic coast from northern Espírito Santo north to Alagoas and Ceará. Occurs more inland in several parts of Bahia. The identity of disjunct populations west of the Rio São Francisco is uncertain.
B. lojanus	Parker, 1930	0	Lojan lancehead	Southern Ecuador in the provinces of Loja and Zamora-Chinchipe at elevations of 2100-2250 m.
B. marajoensis	Hoge, 1966	0	Marajó lancehead	Northern Brazil in the coastal lowlands of the Amazon Delta.
B. microphthalmus	Cope, 1875	0	Small-eyed toadheaded pitviper	Amazonian slopes and lowlands of Colombia, Ecuador, Peru and Bolivia.
B. moojeni	Hoge, 1966	0	Brazilian lancehead	Central and southeastern Brazil, eastern Paraguay, northeastern Argentina (Misiones) and likely eastern Bolivia.
B. neuwiedi	Wagler, 1824	11	Neuwied's lancehead	South America east of the Andes and south of approx. 5° south, including Brazil (southern Maranhão, Piauí, Ceará, Bahia, Goiás, Mato Grosso, an isolated population in Amazonas, Rondônia and all southern states), Bolivia, Paraguay, Argentina (Catamarca, Córdoba, Corrientes, Chaco, Entre Ríos, Formosa, Jujuy, La Pampa, La Rioja, Mendoza, Misiones, Salta, San Juan, San Luis, Santa Fe, Santiago del Estero and Tucumán) and Uruguay.
B. pictus	(Tschudi, 1845)	0	Desert lancehead	Peru on the hills of the Pacific coastal region and versant up to approx. 1800 m elevation.
B. pirajai	Amaral, 1923	0	Piraja's lancehead	Brazil in central and southern Bahia state and possibly also Minas Gerais.
B. pradoi	(Hoge, 1948)	0		Brazil in central Espírito Santo state.
B. sanctaecrucis	Hoge, 1966	0	Bolivian lancehead	Bolivia in the Amazonian lowlands from the departments of El Beni to Santa Cruz.
B. venezuelensis	Sandner Montilla, 1952	0	Venezuelan lancehead	Northern and central Venezuela, including the Cordillera de la Costa (coast range) and the states of Aragua, Carabobo, the Federal District, Miranda, Mérida, Trujillo, Lara, Falcón, Yaracuy and Sucre.

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

Taxonomy

Other (new) species may be encountered in literature, such as:

B. alcatraz - Marques, Martins & Sazima, 2002. Range: Brazil (São Paulo). Common name: jararaca-de-Alcatrazes.
B. muriciensis - Ferrarezzi & Freire, 2001. Range: northeastern Brazil (Alagoas). Common name: Murici lancehead.