The Andaman cobra or Andaman spitting cobra (''Naja sagittifera'') is a species of

cobra COBRA or Cobra, often stylized as CoBrA, was a European avant-garde art group active from 1948 to 1951. The name was coined in 1948 by Christian Dotremont from the initials of the members' home countries' capital cities: Copenhagen (Co), Brussels ...

endemic Endemism is the state of a species being found only 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 foun ...

to the

Andaman Islands The Andaman Islands () are an archipelago, made up of 200 islands, in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a mari ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

. The name of this cobra comes from the Islands itself. The species has a very potent venom, and is capable of “spitting”, although this defensive behavior is very rare and the aim is poor and not as efficient as “true spitting cobras”.

Taxonomy

''Naja sagittifera'' is classified under the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Naja ''Naja'' is a genus of venomous elapid snakes commonly known as cobras (or "true cobras"). Various species occur throughout Africa, Southwest Asia, South Asia, and Southeast Asia. Several other elapid species are often called "cobras", such a ...

'' of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Elapidae Elapidae (, commonly known as elapids , from , variant of "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus '' Emydocephalus ...

. It was first described by Frank Wall, a

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

physician A physician, medical practitioner (British English), medical doctor, or simply doctor is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through the Medical education, study, Med ...

and

herpetologist Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (in ...

in 1913. The generic name ''Naja'' is a Latinization of the

Sanskrit Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...

word ' (), meaning "cobra”. The

specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the final ...

epithet ''sagittifera'' is Latin and means “arrow-bearing” or “carrying arrows”. The Caspian cobra (''Naja oxiana'') and

Monocled cobra The monocled cobra (''Naja kaouthia''), also called monocellate cobra and Indian spitting cobra, is a venomous cobra species widespread across South and Southeast Asia. It is characterized by a distinctive circular or "monocle"-shaped marking on ...

(''Naja kaouthia'') have been demonstrated to be sister clades to ''Naja sagittifera''. Noticeably, despite population separation caused by the

Hindu Kush The Hindu Kush is an mountain range in Central Asia, Central and South Asia to the west of the Himalayas. It stretches from central and eastern Afghanistan into northwestern Pakistan and far southeastern Tajikistan. The range forms the wester ...

mountains, ''N. oxiana'' demonstrates a single evolutionary lineage, suggesting historic rapid range expansion. ''N. oxiana'' is a non-spitter unlike ''N. kaouthia'' and ''N. sagittifera''.

Description

The Andaman cobra is medium to large sized snake in length, is a heavy bodied snake with long cervical ribs capable of expansion to form a hood when threatened, it may also spit its venom into the eyes, although not as accurately as the true spitting cobras. Body is compressed dorsoventrally and sub-cylindrical posteriorly. The average length of these snakes is about , but they can grow to about regularly, although the longest specimen found measured . Adults come in three color patterns: a) Uniform glossy black above, with indistinct black monocle hood mark. Glossy dark-gray below. Head black, with pale white patches on shields. b) Light brown or creamish above, with indistinct black lines round the body and tail and indistinct black monocle hood mark, with brown centre. Pale brown below. Head light brown, spotted with black. c) Uniform grayish above, with distinct black narrow, irregular cross-bars on the body and tail and distinct black monocle hood mark, with gray centre. Grayish below. Head black, with pale white patches on shields. Juveniles have broad black cross-band on throat or underside of neck. Juveniles are glossy black above with a series of narrow, white, irregular cross-bars on body and tail, which show 'A' shape marks when seen from the side. There is a distinct white monocle mark, with black centre. Monocle mark becomes black with the age, also a broad white band below monocle mark disappears with age. Black below. Head black, with some shields blueish-white.

Scalation

Head broad, slightly distinct from neck. Eye medium, with round pupil; nostrils large; frontal small; no loreal; 1 preocular in contact with posterior nasal; 3 postoculars; temporals 2+1 or 2+2. Scales smooth, in 27-29 : 21-23 : 15-17 rows; supralabials 7 ( 3rd and 4th in contact with the eye ), 7th longest, elongated; cuneates 1 on each side; infralabials 8, first 4 touching the first pair of genials; ventrals 172–184; subcaudals 60–64, paired; anal entire.

Distribution

This species is endemic to Andaman and Little

Venom

Using WHO-recommended protocols, venom potencies of this species and its congener from mainland India (''Naja naja'') were evaluated in a murine model of envenoming. The results indicated that the of ''N. sagittifera'' venom was 0.475 mg/kg via

intravenous injection Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...

. Like ''N. kaouthia'' and ''N. atra'', this isn't a “true spitting cobra”. It may, in rare instances, eject venom. If venom gets into the eye, it can cause intense pain and blindness if left untreated. Cobras that cause both extensive & local effects, with or without flaccid paralysis, such as

Naja kaouthia The monocled cobra (''Naja kaouthia''), also called monocellate cobra and Indian spitting cobra, is a venomous cobra species widespread across South and Southeast Asia. It is characterized by a distinctive circular or "monocle"-shaped marking on ...

, generally cause a painful bite, with progressive swelling and, if

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

develops, there is often discolouration of the skin and/or blistering first. This may progress to full thickness skin

over 3–7 days. Such wounds may be extensive, can sometimes involve underlying tissues, and may be difficult to heal. There is a potential for both secondary infection and long term morbidity. Squamous cell carcinoma can develop in such long-term sores. In addition to these local effects, there may be systemic symptoms, such as headache, nausea, vomiting, abdominal pain and less commonly, evidence of mild, sometimes moderate to severe flaccid paralysis. This may develop within a few hours or be delayed (greater than 12 hrs before onset). Ptosis is usually the first sign, followed by

ophthalmoplegia Ophthalmoparesis refers to weakness (-paresis) or paralysis (-plegia) of one or more extraocular muscles which are responsible for eye movements. It is a physical finding in certain neurologic, ophthalmologic, and endocrine disease. Internal ...

, then if it progresses, dysarthria, dysphagia, poor tongue extrusion, drooling, limb weakness, lastly respiratory paralysis. Relative rates of necrosis versus paralysis for ''Naja kaouthia'' vary between studies, but it appears necrosis will develop in about 10-40% of cases, while paralysis occurs in >50% of cases. Infection of the bite area is also common, as high as 58% of cases. Dry bites constitute roughly 20-40% of all bites.

References

{{Taxonbar, from=Q2712316 Naja Reptiles of India Endemic fauna of the Andaman Islands Reptiles described in 1913 Taxa named by Frank Wall