Atheris
Encyclopedia
- Common names: bush vipers.
Atheris is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of venomous
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
vipers
Viperinae
The Viperinae, or viperines, are a subfamily of venomous vipers found in Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the Crotalinae. Currently, 12 genera and 66 species are recognized...
found only in tropical subsaharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
, excluding southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
. Confined to rain forest areas, many members have isolated and fragmented distributions. In an interesting example of convergent evolution, they show many similarities to the arboreal pit vipers
Crotalinae
The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...
of Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. Eight species are currently recognized.
Description
Relatively small in size, with adults ranging in size from 40 cm (A. katangensisAtheris katangensis
Atheris katangensis is a venomous viper species endemic to DR Congo. Found only in a limited area in the east of the country. No subspecies are currently recognized.-Description:...
) to a maximum of 78 cm. (A. squamigera
Atheris squamigera
Atheris squamigera is a venomous viper species found in west and central Africa. No subspecies are currently recognized.-Description:Grows to an average length of 46–60 cm, with a maximum of at least 78 cm. Females are usually larger than males....
).
All species have a broad, triangular head that is distinct from the neck. The canthus
Canthus (snake)
In snakes and amphibians, the canthus, canthal ridge or canthus rostralis, is the angle between the flat crown of the head and the side of the head between the eye and the snout. More specifically, between the supraocular scale and the rostral scale. It is defined as a sharp ridge in many viperids,...
is also distinct and the snout is broad. The crown is covered with small imbricate or smooth scales, none of which are enlarged. The eyes are relatively large eyes with elliptical pupils. The eyes are separated from the supralabials by 1–3 scale rows and from the nasal by 2–3 scales.
The body is slender, tapering and slightly compressed. The dorsal scales are overlapping, strongly keeled
Keeled scales
Keeled scales refer to reptile scales that, rather than being smooth, have a ridge down the center that may or may not extend to the tip of the scale, making them rough to the touch...
and have apical pits. Laterally these are smaller than the middorsals. Midbody there are 14–36 rows of dorsal scales. There are 133–175 rounded ventral scales. The subcaudal scales are single and number 38–67. The tail is strongly prehensile and can support the body while suspended from a branch or a twig.
Members of this group come in an amazing variety of colors and patterns, often within a single species. A. ceratophora
Atheris ceratophora
Atheris ceratophora is a venomous viper species found only in a few mountain ranges in Tanzania. This is the only horned, arboreal viper in Africa. No subspecies are currently recognized.-Description:...
and A. squamigera
Atheris squamigera
Atheris squamigera is a venomous viper species found in west and central Africa. No subspecies are currently recognized.-Description:Grows to an average length of 46–60 cm, with a maximum of at least 78 cm. Females are usually larger than males....
are particularly variable.
Geographic range
Tropical subsaharan AfricaSub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
, excluding southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
.
Some species have only isolated populations, surviving in small sections of ancient rainforest. It is obvious that they once had a much wider distribution, but are now declining.
Habitat
Rainforest regions, mostly in remote areas far from human activity. Some species are threatened by habitat destruction.Behavior
All species are strictly arboreal, although they can sometimes be found on or near the ground.Feeding
Atheris species have been known to prey upon a variety of small amphibians, lizards, rodents, birds and even other snakes. Some species or populations may specialize in eating frogs, but most have been described as opportunistic feeders. Prey is typically ambushed from a hanging position, held until it has succumbed to the venom and then swallowed.Reproduction
All Atheris species are ovoviviparous. Food may be refused during the African "winter" months of July and August. Mating takes place in September-November and the females give birth to live young in March and April.Captivity
A. squamigeraAtheris squamigera
Atheris squamigera is a venomous viper species found in west and central Africa. No subspecies are currently recognized.-Description:Grows to an average length of 46–60 cm, with a maximum of at least 78 cm. Females are usually larger than males....
is reported to do very well in captivity, needing only something to climb on and having no particular temperature requirements. Captive specimens take mice and small birds. However, there have been reports of cannibalism.
Venom
Not much is known about their venom except that it is strongly hemotoxic, causing pain, swelling and blood clotting problems. Until recently, their venom has often been regarded as less toxic than that of many other species, perhaps because bites are uncommon, but this turned out not to be the case. There are now a number of reports of bites that have led to severe hemorrhaging. One case was fatal. Atheris-specific antiveninAntivenin
Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...
does not exist and antivenins meant for bites from other species seem to have little effect, although Echis
Echis
Echis is a genus of venomous vipers found in the dry regions of Africa, the Middle East, Pakistan, India and Sri Lanka. They have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound...
antivenin has been reported to have been of some help in a case of A. squamigera
Atheris squamigera
Atheris squamigera is a venomous viper species found in west and central Africa. No subspecies are currently recognized.-Description:Grows to an average length of 46–60 cm, with a maximum of at least 78 cm. Females are usually larger than males....
envenomation.
Species
| Species | Taxon author | Subsp.* | Common name | Geographic range |
|---|---|---|---|---|
| A. anisolepis Atheris anisolepis Atheris anisolepis is a venomous viper species found in west central Africa. No subspecies are currently recognized.-Geographic range:Found in West central Africa: Gabon, Congo, west DR Congo, north Angola. The type locality given is "d'Alima Lékéti ... Congo ." Broadley limited it to "Alima... |
Mocquard, 1887 | 0 | West central Africa Central Africa Central Africa is a core region of the African continent which includes Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, and Rwanda.... : Gabon Gabon Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west... , Congo Republic of the Congo The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by... , west DR Congo Democratic Republic of the Congo The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world... , north Angola Angola Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city... . |
|
| A. ceratophora Atheris ceratophora Atheris ceratophora is a venomous viper species found only in a few mountain ranges in Tanzania. This is the only horned, arboreal viper in Africa. No subspecies are currently recognized.-Description:... |
Werner Franz Werner Franz Werner was an Austrian zoologist and explorer. Specializing as a herpetologist and entomologist, Werner described numerous species and other taxa of frogs, snakes, insects, and other organisms.... , 1895 |
0 | Horned bush viper | The Usambara Usambara Mountains The Usambara Mountains are a mountain range in North-East Tanzania, approximately long and ranging from 20 to in width. Mountains in the range rise as high as 8,000 ft .... and Uzungwe Mountains in Tanzania Tanzania The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state... . |
| A. chlorechis Atheris chlorechis Atheris chlorechis is a venomous viper species found only in the forests of West Africa. No subspecies are currently recognized.-Description:... T |
(Pel, 1851) | 0 | Western bush viper | West Africa West Africa West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:... including Guinea-Bissau Guinea-Bissau The Republic of Guinea-Bissau is a country in West Africa. It is bordered by Senegal to the north, and Guinea to the south and east, with the Atlantic Ocean to its west.... , Guinea Guinea Guinea , officially the Republic of Guinea , is a country in West Africa. Formerly known as French Guinea , it is today sometimes called Guinea-Conakry to distinguish it from its neighbour Guinea-Bissau. Guinea is divided into eight administrative regions and subdivided into thirty-three prefectures... , Sierra Leone Sierra Leone Sierra Leone , officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of and has an estimated population between 5.4 and 6.4... , Liberia Liberia Liberia , officially the Republic of Liberia, is a country in West Africa. It is bordered by Sierra Leone on the west, Guinea on the north and Côte d'Ivoire on the east. Liberia's coastline is composed of mostly mangrove forests while the more sparsely populated inland consists of forests that open... , Ivory Coast, Ghana Ghana Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south... , Togo Togo Togo, officially the Togolese Republic , is a country in West Africa bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, on which the capital Lomé is located. Togo covers an area of approximately with a population of approximately... , Benin Benin Benin , officially the Republic of Benin, is a country in West Africa. It borders Togo to the west, Nigeria to the east and Burkina Faso and Niger to the north. Its small southern coastline on the Bight of Benin is where a majority of the population is located... , isolated locations in Nigeria Nigeria Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in... , Cameroon Cameroon Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the... , Equatorial Guinea Equatorial Guinea Equatorial Guinea, officially the Republic of Equatorial Guinea where the capital Malabo is situated.Annobón is the southernmost island of Equatorial Guinea and is situated just south of the equator. Bioko island is the northernmost point of Equatorial Guinea. Between the two islands and to the... and Gabon. |
| A. desaixi Atheris desaixi Atheris desaixi is a venomous viper species endemic to Kenya, where only two isolated populations are known. It is known for its striking black and yellow coloration. This species is named in honor of a Peace Corps volunteer who collected the first specimen: Mr. Frank DeSaix... |
Ashe, 1968 | 0 | Mount Kenya bush viper | Two isolated populations in Kenya Kenya Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east... : in the forests at Chuka, south-eastern Mount Kenya Mount Kenya Mount Kenya is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian , Nelion and Point Lenana . Mount Kenya is located in central Kenya, just south of the equator, around north-northeast of the capital Nairobi... , and Igembe in the northern Nyambeni range. |
| A. hispida Atheris hispida Atheris hispida is a venomous viper species found in Central Africa. Known for its extremely keeled scales that give it an almost bristly appearance. No subspecies are currently recognized.-Description:... |
Laurent, 1955 | 0 | Spiny bush viper | Central Africa: DR Congo, south-west Uganda Uganda Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by... , west Kenya. |
| A. katangensis Atheris katangensis Atheris katangensis is a venomous viper species endemic to DR Congo. Found only in a limited area in the east of the country. No subspecies are currently recognized.-Description:... |
Witte, 1953 | 0 | Upemba bush viper | Restricted to Upemba National Park Upemba National Park Upemba National Park is a large park in the Katanga province of the Democratic Republic of Congo. Located in a lush area dotted by lakes, including the eponymous Lake Upemba, and bordered by the Lualaba River, its 11,730 km² dominates the Kibara Plateau.... , Shaba Province Katanga Province Katanga Province is one of the provinces of the Democratic Republic of the Congo. Between 1971 and 1997, its official name was Shaba Province. Under the new constitution, the province was to be replaced by four smaller provinces by February 2009; this did not actually take place.Katanga's regional... in eastern DR Congo. |
| A. mabuensis Atheris mabuensis Atheris mabuensis, or the Mount Mabu forest viper, is a species of snake in the Viperidae family. It is endemic to Mozambique.During his second reconnaissance visit to Mount Mabu a very young forest viper was found by Dr. Julian Bayliss in leaf litter on the floor of closed-canopy wet forest on... |
Branch & Bayliss, 2009 | 0 | Mount Mabu forest viper | Mount Mabu Mount Mabu Mount Mabu is both a mountain and its associated virgin rainforest located in northern Mozambique. The forest covers about 7,000 hectares, while Mount Mabu itself is approximately in elevation. Even though it was known locally, the Mount Mabu forest and its extremely diverse wildlife were unknown... and Mount Namuli Mount Namuli Mount Namuli is the highest peak in the Zambezia Province of Mozambique. With 2,419 metre it is the second highest mountain of Mozambique behind the Monte Binga. The Namuli massif consists of a level plateau which rises 700 to 800 metre. The granite dome of the Namuli rises 1,600 metre above the... , northern Mozambique Mozambique Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest... |
| A. nitschei Atheris nitschei Atheris nitschei is a venomous viper species found in Africa from Uganda and adjacent DR Congo in the north to northern Malawi in the south. Two subspecies are currently recognized, including the nominate subspecies described here.-Description:... |
Tornier, 1902 | 1 | Great Lakes bush viper | Central Africa from east DR Congo, Uganda and west Tanzania southward to north Malawi Malawi The Republic of Malawi is a landlocked country in southeast Africa that was formerly known as Nyasaland. It is bordered by Zambia to the northwest, Tanzania to the northeast, and Mozambique on the east, south and west. The country is separated from Tanzania and Mozambique by Lake Malawi. Its size... and north Zambia Zambia Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west.... . |
| A. squamigera Atheris squamigera Atheris squamigera is a venomous viper species found in west and central Africa. No subspecies are currently recognized.-Description:Grows to an average length of 46–60 cm, with a maximum of at least 78 cm. Females are usually larger than males.... |
(Hallowell, 1854) | 0 | Variable bush viper | West and central Africa: Ivory Coast and Ghana, eastward through southern Nigeria to Cameroon, southern Central African Republic Central African Republic The Central African Republic , is a landlocked country in Central Africa. It borders Chad in the north, Sudan in the north east, South Sudan in the east, the Democratic Republic of the Congo and the Republic of the Congo in the south, and Cameroon in the west. The CAR covers a land area of about ,... , Gabon, Congo, DR Congo, northern Angola, Uganda, Tanzania (Rumanika Game Reserve), western Kenya and Bioko Island. |
*) Not including the nominate subspecies.
T) Type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
.
Taxonomy
Other species may be encountered in literature, such as:- A. acuminata — Broadley, 1998 — western UgandaUgandaUganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...
- A. broadleyi — Lawson, 1999 — CameroonCameroonCameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...
(East Province) - A. hirsuta — Ernst & Rödel, 2002 — Ivory Coast
- A. rungweensis — Bogert, 1940 — south-west Tanzania, north-east Zambia, north Malawi
- A. subocularis — Fischer, 1888 — Cameroon (Southwest Province), extreme east Nigeria
Until relatively recently, these species, all of which are terrestrial, were also included in the genus Atheris:
- Adenorhinos barbouriAdenorhinosAdenorhinos is a monotypic genus created for a venomous viper species, A. barbouri. This is a small and exceptionally rare terrestrial species found only in the Uzungwe and Ukinga mountains of south-central Tanzania in Africa. No subspecies are recognized.-Description:A small species reaching only...
, Uzungwe viper (Loveridge, 1930) - Montatheris hindiiMontatherisMontatheris is a monotypic genus created for a venomous viper species, M. hindii. This is a small terrestrial species found only at high altitude on Mount Kenya and the Aberdare mountain range in Kenya. No subspecies are currently recognized....
, Montane viper, (BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1910) - Proatheris superciliarisProatherisProatheris is a monotypic genus created for a venomous viper species, P. superciliaris. This is a small terrestrial species found in Tanzania, Malawi and Mozambique. No subspecies are currently recognized.-Description:...
, Lowland viper, (PetersWilhelm PetersWilhelm Karl Hartwich Peters was a German naturalist and explorer.He was assistant to Johannes Peter Müller and later curator of the Berlin Zoological Museum. In September 1842 he travelled to Mozambique via Angola. He returned to Berlin with an enormous collection of natural history specimens...
, 1855)
Together with Atheris, these four genera are sometimes referred to as the tribe Atherini.
External links
- Bush vipers at Corallus.com. Accessed 2 August 2007.