Echis ocellatus

Echis ocellatus, known by the common names West African carpet viper[2][3] and ocellated carpet viper,[4] is a highly venomous species of viper endemic to West Africa. No subspecies are currently recognized.[5]

Echis ocellatus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Genus: Echis
Species:
E. ocellatus
Binomial name
Echis ocellatus
Stemmler, 1970
Synonyms
  • Echis carinatus ocellatus Stemmler, 1970
  • Echis ocellatus
    — Hughes, 1976
  • Echis [(Toxicoa)] ocellatus
    — Cherlin, 1990[1]

It is responsible for more human fatalities due to snakebite than all other African species combined.[6] An antivenom called Echitab-plus-ICP[7] is manufactured by the Costa Rican Instituto Clodomiro Picado and another called EchiTabG[8] is manufactured by MicroPharm Ltd in the UK.

Taxonomy

Othmar Stemmler described the species in 1970. It was considered a subspecies of the E. carinatus.

Recent revisions split the species into three, with the recognition of Echis jogeri from Senegal, Guinea and Mali, and Echis romani from eastern Nigeria, southeastern Niger, Cameroon and Chad. [9] [10]

The specific name, ocellatus, is a reference to the distinctive series of "eye-spots" (ocelli) which runs the length of the body.[3]

Common names include African saw-tailed viper, ocellated carpet viper and West African carpet viper.

Description and behavior

The maximum total length (body + tail) is 65 cm (26 in), possibly more, while the average total length is 30–50 cm (12–20 in).[3] They are characterized by their bulging eyes and short snout, typical of species of the genus Echis. E. ocellatus is terrestrial, nocturnal and crespuscular, it usually goes out to hunt its preys at the first hours of the night, preys like small vertebrates, like mammals, birds, lizards and amphibians, it has already been reported hunting small invertebrates like centipedes and scorpions. It's a very aggressive viper; it forms its body like a ''S'' and rubs itself making an alert sound with its scales.[11]

Range and habitat

It is found in West Africa in Mali, Ivory Coast, Burkina Faso, Ghana, Togo, Benin, southern Niger, and Nigeria. Older records from Senegal, Guinea Bissau and Guinea refer to Echis jogeri, and those from eastern Nigeria, Cameroon and southern Chad to Echis romani.

The type locality is described as "Haute Volta, Garango, 048 N, 033 W" (Burkina Faso).[1]

There are also reports of single specimens found in the Bangui in the Central African Republic, and in central Sudan. It is rarely found north of the 15th parallel, after which E. leucogaster becomes more common. The geographic range of E. ocellatus extends to the coast via the Dahomey Gap. They are mainly found in savanna and occasionally in wooded areas.[3][12]

Reproduction

Sexually mature females lay between 6 and 20 eggs, usually at the end of the dry season in February to March. Hatchlings are 10–12 cm (3.9–4.7 in) in total length.

Venom

It's responsible by more fatalities than all other african snakes combined, its venom is compound of Procoagulants, anticoagulants, hemorraghins, nephrotoxins and necrotoxins, symptoms of their bites include local pain, swelling, bleeding necrosis and disfigurement which may result in amputation. Systemic symptoms include coagulopathy, hemorraghes, shock, renal failure and blindness. The envenoming rate is 80% and the lethality rate is 10-20%.[11][13]

References
  1. 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).
  2. Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. 359 pp. ISBN 0-89464-877-2.
  3. Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. ISBN 0-88359-029-8.
  4. Echis ocellatus at Munich AntiVenom INdex (MAVIN). Accessed 3 August 2007.
  5. "Echis ocellatus". Integrated Taxonomic Information System. Retrieved 2 August 2006.
  6. JERRY G. WALLS, The World's Deadliest Snakes, Reptiles (magazine)
  7. "EchiTAb-Plus-ICP Description and Instructions".
  8. Snake Antivenom for Sub – Sharan Africa EchiTAbG (PDF), World Health Organization, 20 June 2019, retrieved 14 December 2019
  9. Pook, C.E.; Joger, U.; Stümpel, N.; Wüster, W. (2009). "When continents collide: Phylogeny, historical biogeography and systematics of the medically important viper genus Echis (Squamata: Serpentes: Viperidae)". Molecular Phylogenetics and Evolution. 53 (3): 792–807. doi:10.1016/j.ympev.2009.08.002. ISSN 1055-7903. PMID 19666129.
  10. Trape, Jean-François (2018). "Partition d'Echis ocellatus Stemmler, 1970 (Squamata, Viperidae), avec la description d'une espèce nouvelle". Bulletin de la Société Herpétologique de France. 167: 13–34.
  11. "WCH Clinical Toxinology Resources". www.toxinology.com. Retrieved 2020-09-16.
  12. "WCH Clinical Toxinology Resources". www.toxinology.com. Retrieved 2020-09-15.
  13. Habib, A. G.; Abubakar, S. B.; Abubakar, I. S.; Larnyang, S.; Durfa, N.; Nasidi, A.; Yusuf, P. O.; Garnvwa, J.; Theakston, R. D. G.; Salako, L.; Warrell, D. A. (September 2008). "Envenoming after carpet viper (Echis ocellatus) bite during pregnancy: timely use of effective antivenom improves maternal and foetal outcomes". Tropical Medicine & International Health. 13 (9): 1172–1175. doi:10.1111/j.1365-3156.2008.02122.x. ISSN 1360-2276. PMC 2857546. PMID 18631310.

Further reading
  • Cherlin VA. 1990. [A taxonomic revision of the snake genus Echis (Viperidae). II. An analysis of taxonomy and description of new forms]. [Proc. Zool. Inst. Leningrad] 207: 193-223. (in Russian).
  • Hughes B. 1976. Notes on African Carpet Vipers, Echis carinatus, E. leucogaster and E. ocellatus (Viperidae, Serpentes). Revue Suisse de Zoologie 83 (2): 359-371.
  • Stemmler O. 1970. Die Sandrasselotter aus Westafrika: Echis carinatus ocellatus subsp. nov. (Serpentes, Viperidae). Revue Suisse de Zoologie 77 (2): 273-282.
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