''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

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 ...

. The smallest member of its

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

, it is distinguished by having a strongly upturned nose and lower scale counts. 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.

Etymology

The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''walli'', is in honor of Ceylonese-born

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

herpetologist Herpetology (from Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and rept ...

Frank Wall.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Hypnale walli'', p. 279).

Description

The smallest member of the genus ''

Hypnale :''Common names: hump-nosed vipers,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. . hump-nosed pit vipers.Brown JH. 1973. Toxi ...

'', the only male with a complete tail measured in total length with a tail of (14% of total length), while the largest female was in total length with a tail of (12% of total length). The body is stoutly built. 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 10 minute 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. It is distinguished from '' H. nepa'' by its lower scale counts. 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 usually lack keels, 7

supralabial scales In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ( ...

, 120-126

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 28-33

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 ...

. Regarding the color pattern, Gloyd and Conant (1990) examined a number of preserved specimens, mentioning that some were so faded as to render the pattern almost invisible. One of these, however, had a faint narrow stripe down the center of its back. In general, the color pattern is described as consisting of a series of 18-24 dorsolateral small subtriangular brown blotches, pointing upwards. These are slightly darker than the ground color, except for the upper edges that may be considerably darker. A pair of dark brown blotches are present on the side of the head, along with a pair of dark stripes curving backward on the sides of the neck. The ventral surface is strongly flecked and dappled with grayish brown.

Geographic range

''Hypnale walli'' is found in

. The type locality given is "Kanneliya Forest, Udugama Southern Province, Ceylon ri Lanka elevation approximately ".

Taxonomy

According to Gloyd and Conant (1990), the taxonomic status of this species is unclear. Although described here as a species, it may eventually be classified as a subspecies of '' H. nepa'', or even as the minimum extreme for ''H. nepa'' with regard to its low

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

and subcaudal scale counts, as well as its relatively short tail.

References

External links