ఇసుక పింజరి

సాధారణ పేర్లు: ఇసుక పింజరి, ఇసుక పొడ.Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN 0-88359-029-8.
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.

Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. 359 pp. ISBN 0-89464-877-2. ఎఖిస్ అనేది పొడపాము అనే అర్ధం వచ్చే గ్రీకు పదంE  at California Plant Names: Latin and Greek Meanings and Derivations. A Dictionary of Botanical Etymology . Accessed 26 January 2007.Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2. ప్రస్తుతానికి వీటిలో ఎనిమిది ప్రజాతులను గుర్తించారు.

వివరణ

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.Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X. 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.Campbell CH. 1995. Snake bite and snake venoms: their effects on the nervous system. In: de Wolff FA, editor. Handbook of clinical neurology, vol 21 (65). Intoxications of the nervous system, part II. Amsterdam: Elsevier Science Publications.

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
SpeciesTaxon authorSubsp.*Common nameGeographic rangeE. carinatusT (Schneider, 1801)4Saw-scaled viperSoutheastern 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. coloratusGünther, 18780Palestine saw-scaled viperSoutheastern 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. hughesiCherlin, 19900Hughes' saw-scaled viperSomalia: northern Migiurtinia, near Meledin.E. jogeriCherlin, 19900Joger's saw-scaled viperWestern and central Mali.E. leucogasterRoman, 19720White-bellied carpet viperWest 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. megalocephalusCherlin, 19900Cherlin's saw-scaled viperRed Sea island between Yemen and Eritrea (Dahlak Archipelago).E. ocellatusStemmler, 19700African saw-scaled viperNorthwest 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)2Egyptian 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:Echis omanensis, Oman saw-scaled viper  at Wolfgang Wüster's homepage . Accessed 7 June 2007.

 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.What Fiery Flying Serpent Symbolized Christ?  at Meridian . Accessed 22 June 2007.

ఇంకా చూడవలసినవి

ప్రామాణికాలు

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

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