''Bothrops alcatraz'', also known as the Alcatrazes lancehead, is a pitviper

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

found only on the Alcatrazes Islands off the coast of southeastern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. No subspecies are currently recognized. Like all pit vipers, it is

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 ...

Description

Grows to a maximum size of 46.2/50.5 cm for males/females. Its small size and relatively large eyes are considered paedomorphic (juvenile) characteristics. Until 15,000 years ago, only common ''

Bothrops ''Bothrops'' is a genus of highly venomous pit vipers Endemism, endemic to the Neotropics.McDiarmid RW, Jonathan A. Campbell, Campbell JA, Touré T. 1999. ''Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1''. Herpetologist ...

'' lived by the island, which was at that time still connected to the continent due to the receded sea waters. When the sea rose back again (with the end of the last glacial period) and the mountain returned to its archipelago status, the ''Bothrops'' that became isolated there quickly fed on all available rodents, which are its main food. They ended up resorting to cockroaches and '' scolopendra'' and, due to their much smaller nutritional value, the snakes slowly shrunk their size until they couldn't grow beyond 50 cm – a process known as

allopatric speciation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

Geographic range

Found only on Ilha Alcatrazes, 35 km off the coast of

São Paulo São Paulo (; ; Portuguese for 'Paul the Apostle, Saint Paul') is the capital of the São Paulo (state), state of São Paulo, as well as the List of cities in Brazil by population, most populous city in Brazil, the List of largest cities in the ...

, southeastern

. This island, which has a total area of only 1.35 km², is one of four islands than make up the Alcatrazes Archipelago. The type locality given is therefore the same: "Alcatrazes Island, (24°06'S, 45°42'W), São Sebastião, São Paulo, Brazil".

Habitat

Described as "low Atlantic Forest vegetation". The highest point on island is .

Conservation status

This species is classified as vulnerable on the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

Red List. Although ''Bothrops alcatraz''t is relatively abundant on Alcatrazes, its range is very small (less than 1.35 km²), making it vulnerable to stochastic events. Previously, the island was used as a Naval target practice area.

Cited references

{{Taxonbar, from=Q2911758

alcatraz Alcatraz Island () is a small island about 1.25 miles offshore from San Francisco in San Francisco Bay, California, near the Golden Gate Strait. The island was developed in the mid-19th century with facilities for a lighthouse, a military fo ...

Snakes of Brazil Endemic reptiles of Brazil Reptiles described in 2002 Taxonomy articles created by Polbot