Calloselasma | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Viperidae |
Subfamily: | Crotalinae |
Genus: | Calloselasma Cope, 1860 |
Species: | C. rhodostoma |
Binomial name | |
Calloselasma rhodostoma (Kuhl, 1824) | |
Synonyms | |
|
Calloselasma is a monotypic genus [3] created for a venomous pit viper species, Calloselasma rhodostoma, which is endemic to Southeast Asia from Thailand to northern Malaysia and on the island of Java. [2] No subspecies are currently recognized. [4]
Attains an average total length of 76 cm (30 in), with females being slightly longer than males. Occasionally, they may grow as long as 91 cm (36 in). [5]
A specimen with a total length of 81 cm (32 in) has a tail 9 cm (3.5 in) long.
Dorsally it is reddish, grayish, or pale brown, with two series of large, dark brown, black-edged triangular blotches, which are alternating or opposite. There is also a thin dark brown vertebral stripe, which may be interrupted or indistinct in some specimens. The upper labials are pink or yellowish, and powdered with brown. There is a broad, dark brown, black-edged diagonal stripe from the eye to the corner of the mouth, with a narrower light-colored stripe above it. Ventrally it is yellowish, uniform or powdered or spotted with grayish brown.
The smooth dorsal scales are arranged in 21 rows at midbody. Ventrals 138-157; anal plate entire; subcaudals 34-54 pairs.
Snout pointed and upturned. Rostral as deep as broad. Two internasals and two prefrontals. Frontal as long as or slightly longer than its distance from tip of snout, as long as or slightly shorter than the parietals. 7-9 upper labials. Loreal pit not in contact with the upper labials. [6]
This is the only Asian pit viper with large crown scales and smooth dorsal scales. [7]
Found in Nepal, Thailand, Cambodia, Laos, Vietnam, northern West Malaysia and on the Indonesian island of Java. The type locality is listed as "Java". [2] There are unconfirmed, but credible reports from southern Myanmar (Burma), northern Sumatra and northern Borneo.
Prefers coastal forests, bamboo thickets, unused and overgrown farmland, orchards, plantations as well as forests around plantations, [5] where it searches for rats and mice.
This species is oviparous and the eggs are guarded by the female after deposition. [7]
This species has a reputation for being bad-tempered and quick to strike. In northern Malaysia it is responsible for some 700 incidents of snakebite annually with a mortality rate of about 2 percent. Remarkably sedentary, it has often been found in the same spot several hours after an incident involving humans. [7] Its venom causes severe pain and local swelling and sometimes tissue necrosis, but deaths are not common. Many victims are left with dysfunctional or amputated limbs due to the lack of antivenom and early treatment. In a 2005 study of 225 Malayan pit viper (Calloselasma rhodostoma) bites in Thailand, most victims had mild to moderate symptoms, but 27 of 145 patients (18.6%) developed permanently swollen limbs. [8] There were only two deaths (related to intracerebral hemorrhage) and no amputations. The antivenin manufactured in Thailand seemed effective in reversing the blood clotting caused by the venom. Most patients remained stable and did not require antivenin. The authors suggested that victims not use traditional healers and avoid overuse of tourniquets. In a prospective phase of the study, bites occurred throughout the year but mostly early in the monsoon season (May and June).
The venom of this species is used to isolate a thrombin-like enzyme called ancrod. [9] This enzyme is used clinically to break down and dissolve thrombi (blood clots) in patients and lower blood viscosity to help prevent heart attack and stroke. [9] [10]
The king cobra is a venomous snake endemic to Asia. The sole member of the genus Ophiophagus, it is not taxonomically a true cobra, despite its common name and some resemblance. With an average length of 3.18 to 4 m and a maximum record of 5.85 m (19.2 ft), it is the world's longest venomous snake. The species has diversified colouration across habitats, from black with white stripes to unbroken brownish grey. The king cobra is widely distributed albeit not commonly seen, with a range spanning from Indian Subcontinent through Southeastern Asia to Southern China, where it preys chiefly on other snakes, including those of its kind. A female king cobra is among few snakes guarding the nest to protect the eggs throughout the incubation period.
Antivenom, also known as antivenin, venom antiserum, and antivenom immunoglobulin, is a specific treatment for envenomation. It is composed of antibodies and used to treat certain venomous bites and stings. Antivenoms are recommended only if there is significant toxicity or a high risk of toxicity. The specific antivenom needed depends on the species involved. It is given by injection.
A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occur. This may result in redness, swelling, and severe pain at the area, which may take up to an hour to appear. Vomiting, blurred vision, tingling of the limbs, and sweating may result. Most bites are on the hands, arms, or legs. Fear following a bite is common with symptoms of a racing heart and feeling faint. The venom may cause bleeding, kidney failure, a severe allergic reaction, tissue death around the bite, or breathing problems. Bites may result in the loss of a limb or other chronic problems or even death.
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom.
Russell's viper is a venomous snake in the family Viperidae native to the Indian subcontinent and one of the big four snakes in India. It was described in 1797 by George Shaw and Frederick Polydore Nodder, and named after Patrick Russell, who wrote about it in his 1796 work An account of Indian serpents, collected on the coast of Coromandel.
Rhabdophis subminiatus, commonly called the red-necked keelback or red-necked keelback snake, is a species of venomous snake in the subfamily Natricinae of the family Colubridae. The species is endemic to Asia.
The Caspian cobra, also called the Central Asian cobra, ladle snake, Oxus cobra, or Russian cobra, is a species of venomous snake in the family Elapidae. The species is endemic to Central Asia. Described by Karl Eichwald in 1831, it was for many years considered a subspecies of the Indian cobra until genetic analysis revealed it to be a distinct species.
Atheris is a genus of vipers known as bush vipers. They are found only in tropical subsaharan Africa and many species have isolated and fragmented distributions due to their confinement to rain forests. Like all other vipers, they are venomous. In an example of convergent evolution, they show many similarities to the arboreal pit vipers of Asia and South America. Seventeen species are currently recognized.
Deinagkistrodon is a monotypic genus created for the venomous pit viper species, Deinagkistrodon acutus, which is endemic to Southeast Asia. No subspecies are currently recognized.
Gloydius blomhoffii, commonly known as the mamushi, Japanese moccasin, Japanese pit viper, Qichun snake, Salmusa or Japanese mamushi, is a venomous pit viper species found in Japan. It was once considered to have 4 subspecies, but it is now considered monotypic.
Naja is a genus of venomous elapid snakes commonly known as cobras. Members of the genus Naja are the most widespread and the most widely recognized as "true" cobras. Various species occur in regions throughout Africa, Southwest Asia, South Asia, and Southeast Asia. Several other elapid species are also called "cobras", such as the king cobra and the rinkhals, but neither is a true cobra, in that they do not belong to the genus Naja, but instead each belong to monotypic genera Hemachatus and Ophiophagus.
Agkistrodon bilineatus is a highly venomous pit viper species found in Mexico and Central America as far south as Honduras.
Ancrod is a defibrinogenating agent derived from the venom of the Malayan pit viper. Defibrinogenating blood produces an anticoagulant effect. Ancrod is not approved or marketed in any country. It is a thrombin-like serine protease.
Venom-induced consumption coagulopathy (VICC) is a medical condition caused by the effects of some snake and caterpillar venoms on the blood. Important coagulation factors are activated by the specific serine proteases in the venom and as they become exhausted, coagulopathy develops. Symptoms are consistent with uncontrolled bleeding. Diagnosis is made using blood tests that assess clotting ability along with recent history of envenomation. Treatment generally involves pressure dressing, confirmatory blood testing, and antivenom administration.
Snake antivenom is a medication made up of antibodies used to treat snake bites by venomous snakes. It is a type of antivenom.
The Papuan black snake is a venomous snake of the family Elapidae native to New Guinea. Reaching around 2 m in length, it is a predominantly black snake coloured grey underneath.
Most snakebites are caused by non-venomous snakes. Of the roughly 3,700 known species of snake found worldwide, only 15% are considered dangerous to humans. Snakes are found on every continent except Antarctica. There are two major families of venomous snakes, Elapidae and Viperidae. 325 species in 61 genera are recognized in the family Elapidae and 224 species in 22 genera are recognized in the family Viperidae, In addition, the most diverse and widely distributed snake family, the colubrids, has approximately 700 venomous species, but only five genera—boomslangs, twig snakes, keelback snakes, green snakes, and slender snakes—have caused human fatalities.
Ram Chandra was a snake showman in Australia. He was known as Australia's "taipan man" and for his work in extracting snake venom to create antivenoms.
The whole blood clotting test is a blood test used to check the coagulation mechanism in the blood following a snake bite. If the test is positive after a bite in South East Asia it indicates the snake was a viper rather than an elapid. It can also be used to assess the effectiveness of antivenin therapy.