The Andaman cobra (Naja sagittifera) is a species of cobraendemic to the Andaman Islands of India. 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”.[3][4]
The Caspian cobra (Naja oxiana) and Monocled cobra (Naja kaouthia) have been demonstrated to be sister clades to Naja sagittifera. Noticeably, despite population separation caused by the Hindu Kush 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. [6][7]
Description
An Andaman cobra in a defensive posture
With its hood lowered
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 0.9 metres (3.0 ft), but they can grow to about 1.5 metres (4.9 ft) regularly, although the longest specimen found measured 1.8 metres (5.9 ft). 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.[8]
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.[9]
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 LD50 of N. sagittifera venom was 0.475 mg/kg via intravenous injection.[11]
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, generally cause a painful bite, with progressive swelling and, if necrosis develops, there is often discolouration of the skin and/or blistering first. This may progress to full thickness skin necrosis 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, 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.[4]
References
^Mohapatra, P.; Achyuthan, N.S. (2021). "Naja sagittifera". IUCN Red List of Threatened Species. 2021: e.T202848A2757313. doi:10.2305/IUCN.UK.2021-3.RLTS.T202848A2757313.en. Retrieved 6 March 2022.
^"Naja sagittifera". The Reptile Database. Retrieved 2021-05-17.
^ ab"Naja sagittifera". Clinical Toxinology Resources. University of Adelaide. Retrieved 2 June 2021.
^Mahoney, KD. "Latin definition for: sagittifer, sagittifera, sagittiferum". La°tdict. Latin Dictionary & Grammar Resources. Retrieved 25 August 2022.
^Kazemi, Elmira; Nazarizadeh, Masoud; Fatemizadeh, Faezeh; Khani, Ali; Kaboli, Mohammad (2021). "The phylogeny, phylogeography, and diversification history of the westernmost Asian cobra (Serpentes: Elapidae: Naja oxiana) in the Trans-Caspian region". Ecology and Evolution. 11 (5): 2024–2039. doi:10.1002/ece3.7144. ISSN 2045-7758. PMC7920780. PMID 33717439.
^Wüster, Wolfgang (1996-04-01). "Taxonomic changes and toxinology: Systematic revisions of the asiatic cobras (Naja naja species complex)". Toxicon. 34 (4): 399–406. doi:10.1016/0041-0101(95)00139-5. ISSN 0041-0101. PMID 8735239.
^"Andaman & Nicobar Snakes". Andaman and Nicobar Islands Environmental Team. Retrieved 2 June 2021.
^Vogel, G (2006). TERRALOG: Venomous Snakes of Asia, Vol. 14 (1st ed.). Frankfurt am Main: Hollywood Import & Export. p. 148. ISBN3936027935.
^Whitaker, R; Captain, A (2008). Snakes of India, The Field Guide (Reprint ed.). Draco Books. ISBN978-8190187305.
^Attarde, S; Khochare, S; Iyer, A; Dam, P; Martin, G; Sunagar, K (25 October 2021). "Venomics of the Enigmatic Andaman Cobra ( Naja sagittifera) and the Preclinical Failure of Indian Antivenoms in Andaman and Nicobar Islands". Frontiers in Pharmacology. 12: 768210. doi:10.3389/fphar.2021.768210. PMC8573199. PMID 34759827.
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andaman, cobra, naja, sagittifera, species, cobra, endemic, andaman, islands, india, name, this, cobra, comes, from, islands, itself, species, very, potent, venom, capable, spitting, although, this, defensive, behavior, very, rare, poor, efficient, true, spitt. The Andaman cobra Naja sagittifera is a species of cobra endemic to the Andaman Islands of India 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 3 4 Andaman cobraConservation statusEndangered IUCN 3 1 1 CITES Appendix II CITES 2 Scientific classificationKingdom AnimaliaPhylum ChordataClass ReptiliaOrder SquamataSuborder SerpentesFamily ElapidaeGenus NajaSpecies N sagittiferaBinomial nameNaja sagittiferaWall 1913Distribution of the Andaman cobra Contents 1 Taxonomy 2 Description 2 1 Scalation 3 Distribution 4 Venom 5 ReferencesTaxonomy EditNaja sagittifera is classified under the genus Naja of the family Elapidae It was first described by Frank Wall a British physician and herpetologist in 1913 The generic name Naja is a Latinization of the Sanskrit word naga न ग meaning cobra The specific epithet sagittifera is Latin and means arrow bearing or carrying arrows 5 The Caspian cobra Naja oxiana and Monocled cobra Naja kaouthia have been demonstrated to be sister clades to Naja sagittifera Noticeably despite population separation caused by the Hindu Kush 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 6 7 Description Edit An Andaman cobra in a defensive posture With its hood lowered 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 0 9 metres 3 0 ft but they can grow to about 1 5 metres 4 9 ft regularly although the longest specimen found measured 1 8 metres 5 9 ft 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 8 Scalation Edit 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 9 Distribution EditThis species is endemic to Andaman and Little Andaman Islands 10 Venom EditUsing 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 LD50 of N sagittifera venom was 0 475 mg kg via intravenous injection 11 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 amp local effects with or without flaccid paralysis such as Naja kaouthia generally cause a painful bite with progressive swelling and if necrosis develops there is often discolouration of the skin and or blistering first This may progress to full thickness skin necrosis 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 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 gt 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 4 References Edit Mohapatra P Achyuthan N S 2021 Naja sagittifera IUCN Red List of Threatened Species 2021 e T202848A2757313 doi 10 2305 IUCN UK 2021 3 RLTS T202848A2757313 en Retrieved 6 March 2022 Appendices CITES cites org Retrieved 2022 01 14 Naja sagittifera The Reptile Database Retrieved 2021 05 17 a b Naja sagittifera Clinical Toxinology Resources University of Adelaide Retrieved 2 June 2021 Mahoney KD Latin definition for sagittifer sagittifera sagittiferum La tdict Latin Dictionary amp Grammar Resources Retrieved 25 August 2022 Kazemi Elmira Nazarizadeh Masoud Fatemizadeh Faezeh Khani Ali Kaboli Mohammad 2021 The phylogeny phylogeography and diversification history of the westernmost Asian cobra Serpentes Elapidae Naja oxiana in the Trans Caspian region Ecology and Evolution 11 5 2024 2039 doi 10 1002 ece3 7144 ISSN 2045 7758 PMC 7920780 PMID 33717439 Wuster Wolfgang 1996 04 01 Taxonomic changes and toxinology Systematic revisions of the asiatic cobras Naja naja species complex Toxicon 34 4 399 406 doi 10 1016 0041 0101 95 00139 5 ISSN 0041 0101 PMID 8735239 Andaman amp Nicobar Snakes Andaman and Nicobar Islands Environmental Team Retrieved 2 June 2021 Vogel G 2006 TERRALOG Venomous Snakes of Asia Vol 14 1st ed Frankfurt am Main Hollywood Import amp Export p 148 ISBN 3936027935 Whitaker R Captain A 2008 Snakes of India The Field Guide Reprint ed Draco Books ISBN 978 8190187305 Attarde S Khochare S Iyer A Dam P Martin G Sunagar K 25 October 2021 Venomics of the Enigmatic Andaman Cobra Naja sagittifera and the Preclinical Failure of Indian Antivenoms in Andaman and Nicobar Islands Frontiers in Pharmacology 12 768210 doi 10 3389 fphar 2021 768210 PMC 8573199 PMID 34759827 This snake article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Andaman cobra amp oldid 1130932417, wikipedia, wiki, book, books, library,
