# Hypnale nepa

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Species of snake

Hypnale nepa Conservation status Endangered (IUCN 3.1)[1] Scientific classification Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Suborder: Serpentes Family: Viperidae Genus: Hypnale Species: H. nepa Binomial name Hypnale nepa (Laurenti, 1768) Synonyms[2] Coluber nepa Laurenti, 1768 Hypnale nepa – Günther, 1864 Crotalus Hypnale nepa – Higgins, 1873 Hypnale walli – Gloyd., 1977 Ancistrodon nepa – M.A. Smith, 1937 Agkistrodon nepa – Taylor, 1950 Hypnale nepa – Gloyd, 1977

***Hypnale nepa***, the **Sri Lankan hump-nosed viper**,[3] is a [venomous](/source/Venomous_snake) [pitviper](/source/Crotalinae) [species](/source/Species) [endemic](/source/Endemism) to [Sri Lanka](/source/Sri_Lanka) where it is known as මූකලන් තෙලිස්සා (mukalan thelissa) in Sinhala. Earlier thought that *[Hypnale walli](/source/Hypnale_walli)* and *Hypnale nepa* were two distinct species, but it is now accepted that it is the same species and *[Hypnale walli](/source/Hypnale_walli)* is a synonym name. Relatively small, they are distinguished by a strongly upturned snout. No [subspecies](/source/Subspecies) are currently recognized.[4]

## Description

Adults grow to a total length of 30–35 cm (11+3⁄4–13+3⁄4 in). According to [Wall](/source/Frank_Wall_(herpetologist)) (1921), the maximum recorded lengths are for a male of 38.7 cm (15+1⁄4 in) and a female of 38.1 cm (15.0 in). According to [Deraniyagala](/source/Paules_Edward_Pieris_Deraniyagala) (1955), the largest specimen in the Colombo museum was 39.2 cm (15+1⁄2 in) in total length with a tail measuring 5.9 cm (2+1⁄4 in). 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.[3]

This species is distinguished from *[H. hypnale](/source/Hypnale_hypnale)* by a snout that has a strongly upturned tip. This is due to an extended [rostral scale](/source/Rostral_scale), which is immediately followed by a raised wart-like hump covered with 7-14 very small scales. Also, the [hemipenes](/source/Hemipenis) have clearly visible spines.[3]

The scalation includes 17 rows of [dorsal scales](/source/Dorsal_scales) at midbody that are weakly [keeled](/source/Keeled_scales) or smooth, 124-142 [ventral scales](/source/Ventral_scales), and 33-41 [subcaudal scales](/source/Subcaudal_scales).[3]

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.[3]

## Geographic range

*Hypnale nepa* is found in [Sri Lanka](/source/Sri_Lanka) throughout [forested](/source/Forest) areas, from lowland [rainforest](/source/Rainforest) to over 1,800 m (5,900 ft) altitude. The [type locality](/source/Type_locality_(biology)) given is "Africa." An obvious error, this was amended to "Sri Lanka" by [Hoge](https://fr.wikipedia.org/wiki/Alphonse_Richard_Hoge) and Romano-Hoge (1981).[2]

## References

1. **[^](#cite_ref-iucn_status_18_November_2021_1-0)** Ukuwela, K., de Silva, A., Kannishka, S., Pushpamal, V. & Kandambi, D. (2021). ["*Hypnale nepa*"](https://www.iucnredlist.org/species/178661/123308135). *[IUCN Red List of Threatened Species](/source/IUCN_Red_List)*. **2021** e.T178661A123308135. Retrieved 18 November 2021.{{[cite journal](https://en.wikipedia.org/wiki/Template:Cite_journal)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. ^ [***a***](#cite_ref-McD99_2-0) [***b***](#cite_ref-McD99_2-1) McDiarmid RW, [Campbell JA](/source/Jonathan_A._Campbell), Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. [ISBN](/source/ISBN_(identifier)) [1-893777-00-6](https://en.wikipedia.org/wiki/Special:BookSources/1-893777-00-6) (series). [ISBN](/source/ISBN_(identifier)) [1-893777-01-4](https://en.wikipedia.org/wiki/Special:BookSources/1-893777-01-4) (volume).

1. ^ [***a***](#cite_ref-G&C90_3-0) [***b***](#cite_ref-G&C90_3-1) [***c***](#cite_ref-G&C90_3-2) [***d***](#cite_ref-G&C90_3-3) [***e***](#cite_ref-G&C90_3-4) [Gloyd HK](/source/Howard_K._Gloyd), [Conant R.](/source/Roger_Conant_(herpetologist)) 1990. Snakes of the *Agkistrodon* Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. [ISBN](/source/ISBN_(identifier)) [0-916984-20-6](https://en.wikipedia.org/wiki/Special:BookSources/0-916984-20-6).

1. **[^](#cite_ref-ITIS_4-0)** ["*Hypnale nepa*"](https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=634894). [Integrated Taxonomic Information System](/source/Integrated_Taxonomic_Information_System). Retrieved 8 August 2008.

## Further reading

- [Laurenti, J.N.](/source/Josephus_Nicolaus_Laurenti) 1768. *Specimen Medicum, Exhibens Synopsin Reptilium Emendatum Cum Experimentis Circa Venena Et Antidota Reptilium Austriacorum*. "Joan. Thom." Vienna. 214 pp. + Plates I.-V. (*Coluber nepa*, p. 97.)

## External links

- [*Hypnale nepa*](http://reptile-database.reptarium.cz/species.php?genus=Hypnale&species=nepa) at the [Reptarium.cz Reptile Database](http://reptile-database.reptarium.cz/). Accessed 8 August 2008.

Taxon identifiers Hypnale nepa Wikidata: Q2710677 Wikispecies: Hypnale nepa ADW: Hypnale_nepa CoL: 6MQ4B EoL: 1056244 GBIF: 2443912 iNaturalist: 31053 IRMNG: 10362204 ITIS: 634894 IUCN: 178661 NCBI: 1297012 Observation.org: 100089 Open Tree of Life: 4120617 RD: nepa Coluber nepa Wikidata: Q109507071 ITIS: 1058636

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