ఇసుక పింజరి

ఇసుక పింజరి
Saw-scaled viper, E. carinatus
Scientific classification
Kingdom:	ఏనిమేలియా
Phylum:	కార్డేటా
Subphylum:	సకశేరుకాలు
Class:	సరీసృపాలు
Order:	Squamata
Suborder:	Serpentes
Family:	వైపరిడే
Subfamily:	Viperinae
Genus:	ఎఖిస్ Merrem, 1820
Synonyms
Echis - Merrem, 1820 Toxicoa - Gray, 1849 Turanechis - Cherlin, 1990

సాధారణ పేర్లు: ఇసుక పింజరి, ఇసుక పొడ.

ఎఖిస్ ఆఫ్రికా, మధ్య ప్రాచ్యం, పాకిస్థాన్, ఇండియా, శ్రీలంక లలోని పొడి ప్రాంతాలలో కనిపించే విషపూరితమైన పొడ పాముల ప్రజాతి.చిన్న వైన పాములైనప్పటికీ, తొందరగా ఆవేశం తెచ్చుకొనే, కాటేయడానికి సిద్ధంగా ఉండే స్వభావాలకి తోడు అతి ప్రమాదకరమైన విషం కలిగి ఉండటంచేత ఇవి అతి ప్రమాదకరమైనవి. ప్రమాదాన్ని సుచించడానికి ఇవి వాటి వంటిపైన ఉండే గరుకు పొలుసులని రుద్ది రంపముతో కోస్తున్న, (అట్టపై ఇసుఅతో రుద్దుతున్నటువంటి) శబ్దము చేస్తాయి.

ఎఖిస్ అనేది పొడపాము అనే అర్ధం వచ్చే గ్రీకు పదం ప్రస్తుతానికి వీటిలో ఎనిమిది ప్రజాతులను గుర్తించారు.

వివరణ

Closeup: scales with serrated keels.

సాధారణంగా చిన్నవిగా ఉండే వీటిలో పెద్దవి మహా అంటే 90 సెం.మీ. మించి పొడవు పెరగవు. (35 in.) (E. pyramidum).

తల పొట్టిగా, వెడల్పుగా బాణం ఆకారంలో మెడనుండి విడిగా ఉంటుంది.మూతి చిన్నగా, గుండ్రంగా ఉంటుంది.కళ్ళు బాగా పెద్దవిగా ఉండి, చక్కగా ముందువైపుకి ఉంటాయి.తలపైభాగం చిన్న, చిన్న, క్రమమైన ఆకారంలేని పొలుసులతో కప్పబడి ఉంటుంది.ఆ పొలుసులు, మృదువుగాకాని, గరుకుగాకాని ఉంటాయి.

శరీరం ఒక మోస్తరు సన్నంగా, గుండ్రంగా ఉంటుంది.వీపు మీది పొలుసులు వంపుగా ఉంటాయి. కానీ పొట్టకిరుపక్కలా ఉండే పొలుసులకు మధ్యన ఎత్తుగా ఉండి పక్కలకు ప్రత్యేకంగా 45దు డిగ్రీల వాలు కలిగి ఉంటాయి. రంపపు పళ్ళలా ఉంటాయి. అందుకే వాటికి ఆ పేరు వచ్చింది. తోక పొట్టిగా ఉంటుంది. The dorsal scales are mostly keeled. However, the scales on the lower flanks stick out at a distinct 45-degree angle and have a central ridge, or keel, that is serrated (hence the common name). The tail is short and the subcaudals single.

విస్తరణ

Found in Pakistan, India and Sri Lanka, parts of the Middle East and Africa north of the equator.

ప్రవర్తన

All members of this genus have a distinctive threat display, which involves forming a series of parallel C-shaped coils and rubbing them together to produce a sizzling sound, rather like water on a hot plate. The proper term for this is stridulation. As they become more agitated, this stridulating behavior becomes faster and louder. It is postulated that this display evolved as a means of limiting water loss, such as might occur when hissing. However, some authors describe this display as being accompanied by loud hissing.

These snakes are very aggressive and will strike vigorously from the position described above. When doing so, they may overbalance and end up moving towards their aggressor as a result; most unusual behavior for a snake.

ఆహారం

Little is known about the eating habits of some Echis species. For others the diet is reported to be extremely varied, and may include items such as locusts, beetles, worms, slugs, spiders, scorpions, centipedes, solifugids, frogs, toads, reptiles (including other snakes), small mammals and birds.

సంతానోత్పత్తి

Most Echis species, such as those found in Africa, are oviparous, while others, such as those in India, are viviparous.

విషం

Bites from Echis species result in more human fatalities than from any other venomous snakes. The genus is recognized as medically significant in many tropical rural areas. They may be small, but they are very aggressive, quick to strike and possess an extremely virulent hemotoxic venom. They are widespread and live in areas that lack modern medical facilities. There seems to be no significant correlation between the length of the specimen and the symptomology signs that occur in humans. Most victims are bitten after dark when these snakes are active.

Most of these species have venom that contains factors that can cause a consumption coagulopathy and defibrination which may persist for days to weeks. This may result in bleeding anywhere in the body, including the possibility of an intracranial hemorrhage. The latter classically occurs a few days following the bite.

Venom toxicity varies among the different species, geographic locations, individual specimens, sexes, over the seasons, different milkings, and of course the method of injection (SC, IM, IP, IV). Consequently, the LD₅₀ values for Echis venom differ significantly. In mice the intravenous LD₅₀ ranges from 2.3 mg/kg (U.S. Navy, 1991) to 24.1 mg/kg (Christensen, 1955) to 0.44-0.48 mg/kg (Cloudsley-Thompson, 1988). In humans, the lethal dose is estimated to be 3–5 mg (Minton, 1967). Latifi (1991) notes that venom from females was more than twice as toxic on average than venom from males.

The amount of venom produced also varies. Reported yields include 20–35 mg of dried venom from specimens 41–56 cm in length (Minton 1974, U.S. Navy, 1991), 6–48 mg (16 mg average) from Iranian specimens (Latifi, 1991) and 13–35 mg of dried venom from animals from various other localities (Boquet, 1967). Yield varies seasonally, as well as between the sexes: the most venom is produced during the summer months and males produce more than females.

జాతులు

Species	Taxon author	Subsp.*	Common name	Geographic range
E. carinatusT	(Schneider, 1801)	4	Saw-scaled viper	Southeastern Arabian Peninsula (Oman, Masirah and eastern UAE), southwestern Iran, Afghanistan, Uzbekistan, Turkmenistan, Tajikistan, Pakistan (including Urak near Quetta and Astola Island off the Makran Coast), India, Sri Lanka and Bangladesh.
E. coloratus	Günther, 1878	0	Palestine saw-scaled viper	Southeastern Egypt east of the Nile and as far south as the 24th parallel, Sinai, Israel, Jordan, and the Arabian Peninsula in Saudi Arabia, Yemen and Oman.
E. hughesi	Cherlin, 1990	0	Hughes' saw-scaled viper	Somalia: northern Migiurtinia, near Meledin.
E. jogeri	Cherlin, 1990	0	Joger's saw-scaled viper	Western and central Mali.
E. leucogaster	Roman, 1972	0	White-bellied carpet viper	West and north-west Africa: extreme southern Morocco, Western Sahara, Algeria (Ahaggar), the southern region of Mauritania, Senegal, northern Guinea, central Mali, Burkina Faso, western Niger and northern Nigeria.
E. megalocephalus	Cherlin, 1990	0	Cherlin's saw-scaled viper	Red Sea island between Yemen and Eritrea (Dahlak Archipelago).
E. ocellatus	Stemmler, 1970	0	African saw-scaled viper	Northwest Africa: Mauritania, Senegal, Mali, Guinea, Ivory Coast, Burkina Faso, Ghana, Togo, Benin, southern Niger, Nigeria, northern Cameroon and southern Chad.
E. pyramidum	(Geoffroy Saint-Hilaire, 1827)	2	Egyptian saw-scaled viper	In northeastern Africa: northern Egypt and central Sudan, Eritrea, Ethiopia, Somalia and northern Kenya. In the southwestern Arabian Peninsula: scattered populations in western Saudi Arabia (south of the 18th parallel), Yemen, South Yemen (Hadhramaut) and Oman (Dhofar). Disjunct populations apparently also occur in the northern regions of Libya, Tunisia and Algeria.

*) Not including the nominate subspecies.
^T) Type species.

శాస్త్రీయ విశ్లేషణ

Some sources also mention several other species:

• E. omanensis, Babocsay 2004. A new species found in the United Arab Emirates and east Oman.
• E. khosatzkii, Cherlin 1990. Found in Oman and Yemen. Considered a synonym of E. pyramidum.
• E. multisquamatus, Cherlin 1981. Described here as E. carinatus multisquamatus.

ఇతర సమాచారం

• A saw scaled viper of the genus Echis may be responsible for biblical claims of a fiery flying serpent.

ఇతరత్రా చదువగలవి

• Boquet P. 1967. Pharmacology and toxicology of snake venoms of Europe and the Mediterranean regions. In: Bucherl W, editor. 1967. Venomous Animals and their Venoms. Vol. I. Paris: Masson. pp 340–58.
• Boulenger GA. 1890. The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia. Taylor & Francis, London, xviii, 541 pp.
• Cherlin, V.A. 1990 Taxonomic revision of the snake genus Echis (Viperidae). II. An analysis of taxonomy and description of new forms [in Russian]. Proceedings of the Zoological Institute, Leningrad, USSR Academy of Schience 207: 193-223[202].
• Christensen PA. 1955. South African Snake Venoms and Antivenins. Johannesburg: South African Institute of Medical Research. 35 pp.
• Cloudsley-Thompson JL. 1988. The saw-scaled viper Echis carinatus. British Herpetological Society Bulletin 24:32-3.
• Gray JE. 1849. Catalogue of the specimens of snakes in the collection of the British Museum. British Museum (Natural History), London. xv, 125 pp.[29].
• Latifi M. 1991. The snakes of Iran. Published by the Department of the Environment and the Society for the Study of Amphibians and Reptiles, 2nd edition. 156 pp.
• Merrem B. 1820. Versuch eines systems der amphibien. Tentamen systematis amphibiorum. J.C. Krieger, Marburg. xv, 191 pp.[149], 1 pl.
• Minton SA Jr. 1967. Snakebite. In: Beeson PB, McDermott W, editors. Cecil and Loeb Textbook of Medicine. Philadelphia: Saunders. 420 pp.
• Minton SA Jr. 1974. Venom Diseases. Springfield (IL) : CC Thomas Publ. 386 pp.
• U.S. Navy. 1991. Poisonous Snakes of the World. US Govt. New York: Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.

బయటి లంకెలు

• Echis at Herpbreeder.com. Accessed 9 September 2006.
• Echis photo gallery at Herpetology of Africa. Accessed 9 September 2006.
• Photograph of a bite to the leg inflicted by saw-scaled viper