''Rhabdophis subminiatus'', commonly called the red-necked keelback or red-necked keelback snake, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

venomous snake Venomous snakes are Species (biology), species of the Suborder (biology), suborder Snake, Serpentes that are capable of producing Snake venom, venom, which they use for killing prey, for defense, and to assist with digestion of their prey. The v ...

in the subfamily Natricinae of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Colubridae Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ever ...

. The species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Description

''Rhabdophis subminiatus'' has a greenish hue with red and yellow regions near the head. It grows to in total length (including tail). Female is much larger than male, mating behavior multiple males may swarm a single female.

Habitat and diet

The red-necked keelback generally lives near ponds, where it consumes frogs and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

Snakebite and venom

''Rhabdophis subminiatus'' is a rear-fanged species and was previously thought to be harmless. However, following one fatal and several near-fatal envenomations, the

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

of its

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

was investigated. As a result, it has recently been reclassified as a dangerous species. Rear-fanged snakes need to bite and hold on, or repeatedly bite, to have any effect on humans. A chewing action facilitates envenomation, as the venom ducts open to fangs that are externally grooved (not hollow) and are posterior in the oral cavity. ''R. subminiatus'' has enlarged and ungrooved teeth. The species has two enlarged teeth in the back of the jaw. Located in the upper jaw is a gland known as

Duvernoy's gland The Duvernoy's gland is a gland found in some groups of ''colubrid'' snakes. It is distinguished from the venom gland and is not found in ''viperids'' or ''elapids''. It was named for French zoologist Georges Louis Duvernoy who first described t ...

, which produces an extremely venomous secretion. Rhabdophis subminiatus

Symptoms caused by venom

When the snake bites, the salivary venom mixture is not injected, but it flows into the punctures produced by the upper jaw's rear teeth, which can penetrate the skin of humans. The venom from ''R. subminiatus'' has been responsible for internal hemorrhaging, including hemorrhaging of the brain, as well as

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

coagulopathy Coagulopathy (also called a bleeding disorder) is a condition in which the blood's ability to coagulate (form clots) is impaired. This condition can cause a tendency toward prolonged or excessive bleeding (bleeding diathesis), which may occur spo ...

, and even

disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts o ...

. Also, when the venom was tested on animals,

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

was reported. Caution should be taken when dealing with patients who have been bitten by the red-necked keelback snake. No further injury such as injections should be used because this may cause excessive bleeding in the bite victim. Although most bites of humans from ''R. subminiatus'' are involved with the front teeth and do not cause adverse effects, rare bites from the rear fangs can be lethal. Studies in mice on the biological activity of the venom of the red-necked keel-back snake, Rhabdophis subminiatus, showed that the venom contained a potent Factor X activator and had intense defibrinogenating activity; the overall proteolytic activity of the venom was low, and this correlated well with its negligible fibrinogenolytic and fibrinolytic activities. Only one antivenom tested was shown to have weak neutralizing activity against the venom in mice. This species of snake has recently been added to the schedule of the Dangerous Wild Animals Act, 1976.

Etymology

Red-necked_Keelback_(Rhabdophis_subminiatus)_紅脖游蛇9

The specific name ''subminiatus'' refers to the typical reddish coloration ("miniatus" = "scarlet, vermilion"), which may be limited to the neck, or more extensive (e.g., photo at left). The subspecific name, ''helleri'', is in honor of American zoologist

Edmund Heller Edmund Heller (May 21, 1875 – July 18, 1939) was an American zoologist. He was President of the Association of Zoos & Aquariums for two terms, from 1935-1936 and 1937-1938. Early life While at Stanford University, he collected specimens in the ...

. Schmidt, Karl P. (1925). "New reptiles and a new salamander from China". ''American Museum Novitates'' (157): 1-5. http://digitallibrary.amnh.org/dspace/handle/2246/9

Geographic range

The red-necked keelback can be found in: *

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

(Sumatra, Borneo, Java, Sulawesi) *

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand t ...

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...

Burma Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

* West

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

Bhutan Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...

Nepal Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

(

Tripura Tripura (, Bengali: ) is a state in Northeast India. The third-smallest state in the country, it covers ; and the seventh-least populous state with a population of 36.71 lakh ( 3.67 million). It is bordered by Assam and Mizoram to the east a ...

Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...

Meghalaya Meghalaya (, or , meaning "abode of clouds"; from Sanskrit , "cloud" + , "abode") is a states and union territories of India, state in northeastern India. Meghalaya was formed on 21 January 1972 by carving out two districts from the state of As ...

West Bengal West Bengal (, Bengali: ''Poshchim Bongo'', , abbr. WB) is a state in the eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabitants within an area of . West Bengal is the fourt ...

Sikkim Sikkim (; ) is a state in Northeastern India. It borders the Tibet Autonomous Region of China in the north and northeast, Bhutan in the east, Province No. 1 of Nepal in the west and West Bengal in the south. Sikkim is also close to the Siligur ...

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

Mizoram Mizoram () is a state in Northeast India, with Aizawl as its seat of government and capital city. The name of the state is derived from "Mizo people, Mizo", the endonym, self-described name of the native inhabitants, and "Ram", which in the Mizo ...

Nagaland Nagaland () is a landlocked state in the northeastern region of India. It is bordered by the Indian states of Arunachal Pradesh to the north, Assam to the west, Manipur to the south and the Sagaing Region of Myanmar to the east. Its capital cit ...

) *

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

(

Yunnan Yunnan , () is a landlocked Provinces of China, province in Southwest China, the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is ...

Guangxi Guangxi (; ; Chinese postal romanization, alternately romanized as Kwanghsi; ; za, Gvangjsih, italics=yes), officially the Guangxi Zhuang Autonomous Region (GZAR), is an Autonomous regions of China, autonomous region of the People's Republic ...

Guangdong Guangdong (, ), alternatively romanized as Canton or Kwangtung, is a coastal province in South China on the north shore of the South China Sea. The capital of the province is Guangzhou. With a population of 126.01 million (as of 2020) ...

Fujian Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its capi ...

Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China ( abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delt ...

Hainan Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slightly l ...

)

References

External links

*
R. subminiatus Snakebite