Hypnale walli
Hypnale walli, or Wall's hump-nosed viper,[2] is a venomous pitviper species endemic to Sri Lanka. The smallest member of its genus, it is distinguished by having a strongly upturned nose and lower scale counts. No subspecies are currently recognized.[3]
| Hypnale walli | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Viperidae |
| Genus: | Hypnale |
| Species: | H. walli |
| Binomial name | |
| Hypnale walli Gloyd, 1977 | |
| Synonyms[1] | |
| |
Etymology
The specific name, walli, is in honor of Ceylonese-born British herpetologist Frank Wall.[4]
Description
The smallest member of the genus Hypnale, the only male with a complete tail measured 30.5 cm (12.0 in) in total length with a tail of 4.3 cm (1+3⁄4 in) (14% of total length), while the largest female was 28.3 cm (11+1⁄4 in) in total length with a tail of 3.5 cm (1+1⁄2 in) (12% of total length). The body is stoutly built.[2]
This species is distinguished from H. hypnale by a snout that has a strongly upturned tip. This is due to an extended rostral scale, which is immediately followed by a raised wart-like hump covered with 10 minute scales. Also, the hemipenes have clearly visible spines. It is distinguished from H. nepa by its lower scale counts.[2]
The scalation includes 17 rows of dorsal scales at midbody that usually lack keels, 7 supralabial scales, 120-126 ventral scales, and 28-33 subcaudal scales.[2]
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.[2]
Geographic range
Hypnale walli is found in Sri Lanka. The type locality given is "Kanneliya Forest, Udugama Southern Province, Ceylon [Sri Lanka], elevation approximately 1,000 ft [300 m]".[1]
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 and subcaudal scale counts, as well as its relatively short tail.[2]
References
- McDiarmid RW, Campbell JA, Touré T (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- 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. ISBN 0-916984-20-6.
- "Hypnale walli". Integrated Taxonomic Information System. Retrieved 8 August 2008.
- Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Hypnale walli, p. 279).
Further reading
- Gloyd HK (1977). "Descriptions of new taxa of crotalid snakes from China and Ceylon (Sri Lanka)". Proc. Biol. Soc. Washington 90: 1002-1015. ("Hypnale walli, new species", pp. 1011-1014).
External links
- Hypnale walli at the Reptarium.cz Reptile Database. Accessed 8 August 2008.