:''Common names'': yarará grande, urutu,Campbell JA, Lamar WW. 2004. ''The Venomous Reptiles of the Western Hemisphere''. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. . wutu,Brown JH. 1973. ''Toxicology and Pharmacology of Venoms from Poisonous Snakes''. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. . ''crossed pit viper.U.S. Navy. 1991. ''Poisonous Snakes of the World''. US Govt. New York: Dover Publications Inc. 203 pp. .'' ''Bothrops alternatus'' is a highly

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

pit viper

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

found in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

(

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

). Within its range, it is an important cause of snakebite. The specific name, ''alternatus'', which is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "alternating", is apparently a reference to the staggered markings along the body. No subspecies are currently recognized.

Description

Size

Large and stout, this terrestrial species reportedly exceeds in total length, although the verified maximum is . Most specimens are in total length, with females being significantly longer and heavier than males.

Color and markings

The scalation includes 25-35 (usually 27-31/29-33 in males/females) rows of

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down t ...

at midbody, 155-183/164-190

ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

in males/females, and 38-53/30-44 subcaudal scales in males/females. On the head there are 8-13 strongly keeled

intersupraocular scales In snakes, the interorbital scales, or intersupraoculars, are the scales on the top of the head between the plates surmounting the eyesWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . ( ...

, 8-10 supralabial scales, none of which are fused with the prelacunal, and 12-14 sublabial scales. The color pattern is exceedingly variable. The ground color may be brown, tan or gray, sometimes with an olive cast. The top of the head is usually chocolate brown to almost black with a range of transverse and longitudinal tan to white markings. On the body, there is a series of 22-28 dorsolateral markings that are chocolate brown to black in color and boldly bordered in cream or white. Along the vertebral line, these markings may either oppose or alternate. Each marking is widened and invaded from underneath by the paler ground color so that it either looks like a cross, encloses a darker blotch, or divides the marking into three parts to give it the shape of a headphone. On the tail, the pattern fuses to form a zigzag pattern. In some specimens, the pattern is so concentrated that there is no difference in color between the markings and the interspaces. The ventral surface includes a dark brown to black stripe that starts at the neck and runs down to the tail tip. Aberrant specimens, described by Lema (1960, 1987), had dark dorsal stripes running down the length of the body.

Common names

''Urutu'', ''wutu'', crossed pit viper. The common names ''urutu'' and ''wutu'' refer to the crescent markings on the body.Mehrtens JM. 1987. ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . In

, it is referred to as ''víbora de la cruz'' and ''yarará grande''. In

it is called ''boicoatiara'', ''boicotiara'' (Tupi dialect), ''coatiara'', ''cotiara'' (southern Brazil), ''cruzeira'', ''cruzeiro'', ''jararaca de agosto'' (Rio Grande do Sul, Lagoa dos Patos region), ''jararaca rabo-de-porco'' (Rio Grande do Sul), and ''urutu''. In

it is called ''mbói-cuatiá'', ''mbói-kwatiara'' (Gí dialect), and ''yarará acácusú'' (Guaraní dialect). In

it is referred to as ''crucera'', ''víbora de la cruz'' and ''yarará''.

Geographic range

Found in southeastern

and northern

. In Argentina it is found in the provinces of

Buenos Aires Buenos Aires ( or ; ), officially the Autonomous City of Buenos Aires ( es, link=no, Ciudad Autónoma de Buenos Aires), is the capital and primate city of Argentina. The city is located on the western shore of the Río de la Plata, on South ...

, Catamarca, Córdoba,

Corrientes Corrientes (; Guaraní: Taragüí, literally: "Currents") is the capital city of the province of Corrientes, Argentina, located on the eastern shore of the Paraná River, about from Buenos Aires and from Posadas, on National Route 12. It ha ...

, Chaco, Entre Ríos, Formosa,

La Pampa La Pampa () is a sparsely populated province of Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it ...

Misiones Misiones (, ''Missions'') is one of the 23 provinces of Argentina, located in the northeastern corner of the country in the Mesopotamia region. It is surrounded by Paraguay to the northwest, Brazil to the north, east and south, and Corrientes P ...

, San Luis, Santa Fe, Santiago del Estero and Tucumán. The type locality is listed as "Amérique méridionale" and "Paraguay."

Habitat

Occurs in tropical and semitropical forests, as well as

temperate deciduous forest Temperate deciduous or temperate broad-leaf forests are a variety of temperate forest 'dominated' by trees that lose their leaves each year. They are found in areas with warm moist summers and cool winters. The six major areas of this forest type ...

s. According to Gallardo (1977), it prefers marshes, low-lying swamps,

riparian zone A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...

s and other humid habitats. It is also said to be common in sugarcane plantations. It is found in a variety of habitats depending on the latitude, including open fields and rocky areas in the Sierra de Achiras in Córdoba and the Sierra de la Ventana in

, fluvial areas, grasslands and

cerrado The ''Cerrado'' (, ) is a vast ecoregion of tropical savanna in eastern Brazil, particularly in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Minas Gerais, and the Federal District. The core areas of the Cerrado biome are the ...

. However, it is usually absent in dry environments.

Reproduction

Females, depending on their size, give birth to varying numbers of live young. Leitão de Araujo and Ely (1980) reported on two litters that had average weights of and and average total lengths of and , with captive females giving birth to 3-12 young. Cardinale and Avila (1997) collected one female in 1995 that was found to contain 26 embryos. Haller and Martins (1999) determined that the species produces 1-24 offspring at a time. Neonates are identical to the adults, except that they are more brightly colored. Neonates are capable of a venomous strike immediately when they are born.

Venom

An important cause of snakebite within its range, bites are rarely fatal but frequently cause severe local tissue damage. Although Spix and Martius (1824) found that it had a reputation for being one of the most venomous snakes in

, its bite ''"said to occasion almost certain death"'', the statistics tell a different story. In his survey of 6,601 snakebite cases in Central and

, Fonseca (1949) found that 384 were attributed to this species and that, of that number, only eight were fatal (2%).Warrell DA. 2004. Snakebites in Central and South America: Epidemiology, Clinical Features, and Clinical Management. ''In'' Campbell JA, Lamar WW. 2004. ''The Venomous Reptiles of the Western Hemisphere''. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. . In a study by Baub ''et al.'' (1994) of the case histories of 32 patients bitten by this species and admitted to the hospital in

Catanduva Catanduva is a municipality in the state of São Paulo, Brazil. The population is 122,497 (2020 est.) in an area of 290.59 km2. Is the second largest city in the Northern part of the state, after São José do Rio Preto. The city has a divers ...

São Paulo São Paulo (, ; Portuguese for ' Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...

, Brazil, all developed local pain and swelling. Furthermore, in 97% of all cases the blood clotting time was prolonged (more than 12 minutes), 41% had bleeding (usually from the gums), 32% had local blistering and 9% had necrosis. In all cases, specific

antivenin Antivenom, also known as antivenin, venom antiserum, and antivenom immunoglobulin, is a specific treatment for envenomation. It is composed of antibodies and used to treat certain venomous bites and stings. Antivenoms are recommended only if th ...

was used and there were no deaths. These findings contrast with other reports involving much more tissue damage. Silva Jr. (1956) includes a description of a Brazilian patient with gangrene on the hand and forearm that required amputation, as well as another bitten four years previously who had scarring over the anterior

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

l compartment. Abalos and Pirosky (1963) considered this species to be responsible for many of the total number of snakebite cases in

and included a picture of a young boy, bitten below the knee, with the bare

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity i ...

and tibia exposed. In 2004, a 44-year-old woman died from a bleed in the brain after getting bitten at her home. The median lethal dose of this species in Brazil varies according to the location, from to .

References

External links

* *. Accessed 9 April 2019. The repeated "cross" motif on its sides gives rise to its Spanish common name ''víbora de la cruz''. {{Taxonbar, from=Q1840955 Reptiles described in 1854 alternatus Reptiles of Argentina Reptiles of Brazil Reptiles of Paraguay Reptiles of Uruguay Taxa named by Gabriel Bibron Taxa named by André Marie Constant Duméril Taxa named by Auguste Duméril