Common names: black-headed bushmaster.

Lachesis melanocephala is a venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 pitviper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 found in Costa Rica

Costa Rica

Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

. No subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 are currently recognized.

Description

Adults frequently grow to 190–200 cm in length with the largest reported specimens being 230 cm (Solórzano, 2004) and 240 cm (Ripa, 2001). The top of the head is uniform black in color.

Geographic range

Found in Costa Rica

Costa Rica

Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

 on the Pacific versant of southeastern Puntarenas

Puntarenas

Puntarenas is the capital and largest city in the province Puntarenas, Costa Rica, at the Pacific coast. The eponymous and oddly shaped province has its largest section in the South, far from the capital.Some 100,000 live in the city and close towns...

 province from near sea level to about 1500 m. The type locality given is "tropical rainforest 9 km northern of Ciudad Neily in southeastern Provincia de Puntarenas, Costa Rica."

Campbell and Lamar (2004) describe its range as southwestern Costa Rica and possibly extreme western Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

, but state that almost all locality records are from Puntarenas province.