''Hypnale nepa'', the Sri Lankan hump-nosed viper, Gloyd HK, Conant R. 1990. Snakes of the ''Agkistrodon'' Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. . is a

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 ...

pitviper The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfa ...

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 ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

where it is known as මූකලන් තෙලිස්සා (mukalan thelissa) in Sinhala. Earlier thought that ''

Hypnale walli ''Hypnale walli'', or Wall's hump-nosed viper, Gloyd HK, Conant R (1990). ''Snakes of the ''Agkistrodon'' Complex: A Monographic Review''. Oxford, Ohio: Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. . is a v ...

'' and ''Hypnale nepa'' were two distinct species, but it is now accepted that it is the same species and ''

'' is a synonym name. Relatively small, they are distinguished by a strongly upturned snout. No

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are currently recognized.

Description

Adults grow to a total length of . According to

Wall A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including: * Walls in buildings that form a fundamental part of the supe ...

(1921), the maximum recorded lengths are for a male of and a female of . According to

Deraniyagala Deraniyagala is a town in the Kegalle district in the Sabaragamuwa Province of Sri Lanka. Deraniyaga city area consists major government administrative offices, textile industries and transportation hub and the district hospital which has seve ...

(1955), the largest specimen in the Colombo museum was in total length with a tail measuring . In general, the tail is 13-18% of total body length. The body is moderately slender with a head that is conspicuously distinct from the neck. This species is distinguished from '' H. hypnale'' by a snout that has a strongly upturned tip. This is due to an extended

rostral scale The rostral scale, or rostral, in snakes and other scaled reptiles is the median plate on the tip of the snout that borders the mouth opening. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: ...

, which is immediately followed by a raised wart-like hump covered with 7-14 very small scales. Also, the

hemipenes A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamata, squamates (snakes, lizards and amphisbaenia, worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erecti ...

have clearly visible spines. The scalation includes 17 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. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

at midbody that are weakly keeled or smooth, 124-142

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 conta ...

, and 33-41

subcaudal scales In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...

. The color pattern consists of a light brown to dark brown to pale olive ground color, flecked and mottled with darker tones. This is overlaid with a series of 17-26 dorsolateral suboval or subtriangular brown blotches that alternate or oppose each other middorsally. These blotches are 3-4 scales wide and extend down to the third scale row. The top of the head is brown and usually lacks any pattern except for a black postorbital stripe that extends to the neck.

Geographic range

''Hypnale nepa'' is found in

throughout

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

ed areas, from lowland

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

to over altitude. The type locality given is "Africa." An obvious error, this was amended to "Sri Lanka" by Hoge and Romano-Hoge (1981).

References

External links

nepa The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.Un ...

Reptiles of Sri Lanka Reptiles described in 1768 Taxa named by Josephus Nicolaus Laurenti {{Alethinophidia-stub

Description

Geographic range

References

Further reading

External links