| Deinagkistrodon | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Viperidae |
| Subfamily: | Crotalinae |
| Genus: | Deinagkistrodon Gloyd, 1979 |
| Species: | D. acutus |
| Binomial name | |
| Deinagkistrodon acutus (Günther, 1888) | |
| Synonyms | |
| |
Deinagkistrodon is a monotypic genus [4] created for the pit viper species, Deinagkistrodon acutus, which is endemic to Southeast Asia. [2] No subspecies are currently recognized. [5]
Deinagkistrodon acutus is light brown or greyish brown dorsally, with a series of dark brown lateral triangles on each side. The two pointed tops of the two opposite triangles meet each other at the mid-line, forming a series of about 20 light brown, squarish blotches on the back. A row of large black spots extends along each side near the belly. The top and upper sides of the head are uniformly black, with a black streak from the eye to the angle of the mouth. D. acutus is yellowish ventrally, spotted with dark brown. The young are much lighter than the adults with essentially the same pattern. The head is large, triangular, with an upturned snout. The body is very stout. The tail is short, ending in a compressed, pointed slightly curved cornified scale. The top of the head is covered with nine large shields. The dorsal scales are strongly and tubercularly keeled. The subcaudals are mostly in pairs, some of the anterior ones are single. This stout snake, usually between 0.8 and 1.0 metre (2.6 and 3.3 ft) in total length (including tail), reaches a maximum total length of 1.57 metres (5.2 ft) in males and 1.41 metres (4.6 ft) in females. [6] The largest specimen on record measured approximately 1.549 metres (5.08 ft). [7]
Common names for D. acutus include sharp-nosed viper, snorkel viper, hundred pacer, [8] Chinese moccasin, [9] Chinese copperhead, [10] five-pacer, hundred-pace snake, long-nosed pit viper, sharp-nosed pit viper, [11] hundred-pace pit viper. [12] The snake has been an object of veneration by indigenous Taiwanese peoples.
Deinagkistrodon acutus is found in southern China (Zhejiang, Fujian, Hunan, Hubei, Guangdong), Taiwan, northern Vietnam, and possibly Laos. The type locality was not included in the original description. It was later given as "Wusueh [ Wuxue ], Hupeh [ Hubei ] Province, China" by Pratt (1892) and Pope (1935). Listed as "Mountains N. of Kiu Kiang [ Jiujiang ]" in the catalogue of the British Museum of Natural History. [2]
The species D. acutus inhabits high, forested mountains up to 1,350 metres (4,430 ft), but has also been found in low coastal regions (100 metres (330 ft)). It prefers lower mountain slopes or rocky hills with small valleys. [6]
The diet of D. acutus consists of small mammals such as rats and mice, birds, toads, frogs and lizards. Chinese herpetologist Zhao Ermi reported a specimen of a total length of 1.04 metres (3.4 ft) and weighing 600 grams (1.3 lb) having eaten a specimen of Rattus rattus of a total length of 51.5 centimetres (20.3 in) and a weight of 530 grams (1.17 lb). [6]
As one of the few oviparous pit vipers, D. acutus can lay up to 24 eggs, which may be retained during initial incubation, an adaptation that shortens post-deposition incubation time. However, it generally only deposits 11 or 12 eggs from June to August. Egg size is 40–56 x 20–31 mm (about 2 × 1 in). Hatchlings are lighter and more vividly patterned than the adults, but this darkens considerably with age. [8] [6]
Dangerous animals often have exaggerated reputations and the species D. acutus is no exception. The popular name "hundred pacer" refers to a local belief that, after being bitten, the victim will only be able to walk 100 steps before dying. In some areas, it has even been called the "fifty pacer" or, in extreme examples, the "five-step snake." This often causes bite victims to needlessly amputate or burn bitten fingers or limbs, resulting in further complications like the loss of the amputated body part or gangrene. Nevertheless, this species is considered dangerous, and fatalities are not unusual. An antivenom is produced in Taiwan. [8] [13]
Brown (1973) mentions a venom yield of up to 214 mg (dried) and LD50 (toxicity) values of 0.04 mg/kg IV, 4.0 mg/kg IP and 9.2–10.0 mg/kg SC. [14] The venom contains at least four hemorrhagins Acutolysin A, B, C [15] and D. [16]
According to the US Armed Forces Pest Management Board, the venom is a potent hemotoxin that is strongly hemorrhagic. Bite symptoms include severe local pain and bleeding that may begin almost immediately. This is followed by considerable swelling, blistering, necrosis, and ulceration. Systemic symptoms, which often include heart palpitations, may occur suddenly and relatively soon after the bite. [9] Because of its body size and large hinged fangs which permit effective delivery of large quantities of venom, victims bitten by this snake should be treated accordingly.
The venom of this species is commonly used for research purposes. Researchers have found that this venom contains protease activity, meaning it attacks and degrades intra- and extracellular proteins. [17] If injected into mice, within 2 hours the venom begins a process known as mesangiolysis (the degeneration and death of cells that line the inner layer of the glomerulus and regulate glomerular filtration in the kidney). [17] Eventually, the kidneys no longer function and the mouse dies. [18]
When controlled, the venom has some clinical application. D. acutus snake venom contains a protein called ACTX-6. [19] This protein was shown to induce apoptosis (cell death) in isolated cancer cells through Fas pathway activation. [19] Fas is a protein that becomes a death receptor in the cellular membrane. When activated, Fas turns on what is called a "caspase cascade". [20] This pathway is made up of a series of proteins called initiator and executioner caspases. Initiator caspases help form an apoptosis initiation factor that eventually activates executioner caspases (see figure 3). Executioner caspases go on to "digest" the cell from the inside out. They cleave cytoskeleton filaments and DNA until the cell completely implodes. [20]
Deinagkistrodon acutus venom has been used in traditional Chinese medicine for centuries to extract antivenin that is successfully used to treat snakebites. [21] [22] Different parts of the snake are also prescribed to help alleviate ailments known as "wind diseases". [21] Because these snakes move so quickly, substances from their bodies are thought to easily treat these fast-moving "wind" syndromes. D. acutus is currently used in patients with arthritis, leprosy, tetanus, boils, and, as previously mentioned, tumors. [23] The same qualities that make snakes flexible, capable of regenerating skin, and able to inflict paralysis could be transferred to human conditions if applied medicinally. [24] The vipers are prepared by cooking the flesh of the headless body, grinding a paste of snake ash and mixing it with honey, drying the snake and compacting it into a powder, or even injecting their venom intravenously. [24] Although these practices are common in Chinese medicine, no current studies have affirmed the effectiveness of these treatments. Whether these "cures" simply have a placebo effect or actually heal the patients is not known.
The eastern copperhead, also known simply as the copperhead, is a species of venomous snake, a pit viper, endemic to eastern North America; it is a member of the subfamily Crotalinae in the family Viperidae.
Agkistrodon piscivorus is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. It is one of the world's few semiaquatic vipers, and is native to the Southeastern United States. As an adult, it is large and capable of delivering a painful and potentially fatal bite. When threatened, it may respond by coiling its body and displaying its fangs. Individuals may bite when feeling threatened or being handled in any way. It tends to be found in or near water, particularly in slow-moving and shallow lakes, streams, and marshes. It is a capable swimmer, and like several species of snakes, is known to occasionally enter bays and estuaries and swim between barrier islands and the mainland.
The Crotalinae, commonly known as pit vipers, or pit adders, are a subfamily of vipers found in Asia and the Americas. Like all other vipers, they are venomous. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on both sides of the head. Currently, 23 genera and 155 species are recognized: These are also the only viperids found in the Americas. The groups of snakes represented here include rattlesnakes, lanceheads, and Asian pit vipers. The type genus for this subfamily is Crotalus, of which the type species is the timber rattlesnake, C. horridus.
Agkistrodon is a genus of pit vipers commonly known as American moccasins. The genus is endemic to North America, ranging from the Southern United States to northern Costa Rica. Eight species are currently recognized, all of them monotypic and closely related. Common names include: cottonmouths, copperheads, and cantils.
Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long, hinged fangs that permit deep penetration and injection of their venom. Three subfamilies are currently recognized. They are also known as viperids. The name "viper" is derived from the Latin word vipera, -ae, also meaning viper, possibly from vivus ("living") and parere, referring to the trait viviparity common in vipers like most of the species of Boidae.
Gloydius is a genus of pit vipers endemic to Asia, also known as Asian moccasins or Asian ground pit vipers. Named after American herpetologist Howard K. Gloyd, this genus is very similar to the North American genus Agkistrodon. 24 species are currently recognized.
Russell's viper is a highly venomous snake in the family Viperidae native to South Asia. It was described in 1797 by George Shaw and Frederick Polydore Nodder. It is named after Patrick Russell and is one of the big four snakes in India.
Bothriechis schlegelii, known commonly as the highlandeyelash-pitviper or Schlegel'seyelash-pitviper, is a species of pit viper in the family Viperidae, native to Latin America. Somewhat small, arboreal snakes, B. schlegelii is perhaps best known for the namesake superciliary ("eyelash") scales above its eyes, and for having distinctly keeled or "raised" scales covering the bulk of its body. The species is also known for producing a veritable rainbow of color forms (morphs). It is the most common of the green palm-pitvipers, and is often present in zoological exhibits, owing to its general hardiness. The specific name schlegelii honors Hermann Schlegel, who was a German ornithologist and herpetologist.
Gloydius himalayanus also known as the Himalayan pit viper or the Himalayan viper is a pit viper species found along the southern slopes of the Himalayas in Pakistan, India and Nepal. No subspecies are currently recognized. Himalayan pit vipers have been found up to 4900m above sea level, which makes it the highest living snake ever found.
The eastern diamondback rattlesnake is a species of pit viper in the family Viperidae. The species is endemic to the Southeastern United States. It is one of the heaviest venomous snakes in the Americas and the largest rattlesnake. No subspecies are recognized.
Echis is a genus of vipers found in the dry regions of Africa, the Middle East, India, Sri Lanka and Pakistan. They have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound. The name Echis is the Latin transliteration of the Greek word for "viper" (ἔχις). Like all vipers, they are venomous. Their common name is "saw-scaled vipers" and they include some of the species responsible for causing the most snakebite cases and deaths in the world. Twelve species are currently recognized.
Calloselasma is a monotypic genus created for a pit viper species, Calloselasma rhodostoma, which is endemic to Southeast Asia from Thailand to northern Malaysia and on the island of Java. 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 pit viper species found in Japan. It was once considered to have 4 subspecies, but it is now considered monotypic.
Agkistrodon bilineatus is a highly venomous pit viper species found in Mexico and Central America as far south as Honduras.
The Florida cottonmouth is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. The species is endemic to the United States, where it occurs in southern Georgia and the Florida peninsula in nearly every type of wetlands in the region, including brackish water and offshore islands. However, it is not entirely dependent on water and is occasionally encountered as far as a mile from surface water. Agkistrodon conanti venom is very hemolytic and known to cause relatively extensive necrosis compared to many snake venoms, and can sometimes be lethal with a 17% mortality rate. It is often confused with harmless watersnakes (Nerodia) and other semi-aquatic species with which it shares its habitat.
Agkistrodon contortrix pictigaster was formerly a venomous pit viper subspecies found in the Trans-Pecos region of the United States in western Texas, and northeastern Mexico. However, recent taxonomic changes do not recognize the Trans-Pecos copperhead as a valid taxon.
Gloydius halys is a pit viper species found within a wide range that stretches across Asia, from Russia, east of the Urals, eastwards through China. Five subspecies are currently recognized, including the nominotypical form described here.
Gloydius brevicauda is a pit viper species endemic to China and the Korean Peninsula.
Venom in snakes and some lizards is a form of saliva that has been modified into venom over its evolutionary history. In snakes, venom has evolved to kill or subdue prey, as well as to perform other diet-related functions. While snakes occasionally use their venom in self defense, this is not believed to have had a strong effect on venom evolution. The evolution of venom is thought to be responsible for the enormous expansion of snakes across the globe.
