Proatheris
Encyclopedia
- Common names: lowland viper, swamp viper, lowland swamp viper, eyebrow viper, more.
Proatheris is a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
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...
created for a 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...
viper
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...
species, P. superciliaris. This is a small terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
species found 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...
, 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 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...
. No subspecies are currently recognized.
Description
A small species that averages 40 to 50 cm and a maximum of 61 cm in length. The females are slightly larger than the males. The head has a somewhat elongated appearance, the top of which is covered with small scales except for a pair of large supraocular scalesSupraocular scales
In scaled reptiles, supraocular scales are scales on the crown immediately above the eye. The size and shape of these scales are among the many characteristics used to differentiate species from each another....
, which are almost twice as long as they are wide.
Common names
Lowland viper, swamp viper, lowland swamp viper, eyebrow viper, swamp adder, Peter's viper, flood-plain viper, Mozambique viper, African lowland viper, domino viper.Geographic range
East AfricaEast Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
. The southern part of its range begins near Beira
Beira, Mozambique
Beira is the second largest city in Mozambique. It lies in the central region of the country in Sofala Province, where the Pungue River meets the Indian Ocean. Beira had a population of 412,588 in 1997, which grew to an estimated 546,000 in 2006...
, in central 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...
, extends up north over the Mozambique Plain to Quissanga, and through 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 as far north as the floodplains of southern 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...
at the northern end of Lake Malawi
Lake Malawi
Lake Malawi , is an African Great Lake and the southernmost lake in the Great Rift Valley system of East Africa. This lake, the third largest in Africa and the eighth largest lake in the world, is located between Malawi, Mozambique, and Tanzania...
. The type locality given is "Terra Querimba" (Quissanga mainland opposite Ilha Quirimba, Mozanbique).
Its range it apparently centered around the lower section of the Zambezi River and spreads out into the coastal plain of central Mozambique and the Shire Valley to Lake Chilwa
Lake Chilwa
Lake Chilwa is the second-largest lake in Malawi after Lake Malawi. It is in eastern Zomba District, near the border with Mozambique. Approximately 60 km long and 40 km wide, the lake is surrounded by extensive wetlands....
and Malawi. However, other specimens have been found far from this region, such as in Cape Delgado Province, in north-eastern Mozambique, and Mwaya in south-western Tanzania.
Habitat
Almost always found in low-lying marshes, floodplains and land frequently used for grazing cattle. The soil is never too dry, since this would make it difficult for the rodents that they feed on to dig their burrows. These snakes are entirely terrestrial and are usually found in or around these rodent burrows.Behavior
One of the distinguishing characteristics of the AtherisAtheris
Atheris is a genus of venomous vipers found only in tropical subsaharan Africa, excluding southern Africa. 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...
group (to which Proatheris is closely related), is that they have prehensile tails. With Proatheris, the young and subadults have this capability, but it is diminished in the adults.
Venom
First known case reported by Els (1988) involving a 20 cm juvenile and 24-year-old victim penetrated by a single fang. The results were painful, but there were none of the strongly hemotoxicHemotoxin
Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells , disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term hemotoxin is to some degree a misnomer since toxins that damage the blood also damage other tissues...
symptoms that had been associated with Atheris
Atheris
Atheris is a genus of venomous vipers found only in tropical subsaharan Africa, excluding southern Africa. 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...
venom up to that point.
In a second case in 1996, however, the victim experienced severe hemolysis
Hemolysis
Hemolysis —from the Greek meaning "blood" and meaning a "loosing", "setting free" or "releasing"—is the rupturing of erythrocytes and the release of their contents into surrounding fluid...
and complete platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
destruction after which the liver and kidneys began to fail. When it was feared that the patient may die from hemolytic-uremic syndrome
Hemolytic-uremic syndrome
Hemolytic-uremic syndrome , abbreviated HUS, is a disease characterized by hemolytic anemia, acute renal failure and a low platelet count . It predominantly, but not exclusively, affects children. Most cases are preceded by an episode of diarrhea caused by E. coli O157:H7, which is acquired as a...
, a plasmapheresis
Plasmapheresis
Plasmapheresis is the removal, treatment, and return of blood plasma from blood circulation. It is thus an extracorporeal therapy...
was performed. Luckily, the patient survived, but it is now obvious that P. superciliaris venom is very hemotoxic
Hemotoxin
Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells , disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term hemotoxin is to some degree a misnomer since toxins that damage the blood also damage other tissues...
.
Taxonomy
This species was previously placed in the genus AtherisAtheris
Atheris is a genus of venomous vipers found only in tropical subsaharan Africa, excluding southern Africa. 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...
based on skull characteristics and because of its partially prehensile tail. The name Proatheris is Latin for "before-atheris".
External links
- Proatheris at Herpbreeder.com. Accessed 26 September 2006.
- Proatheris superciliaris image at Swissherp.org. Accessed 8 October 2006.
- Proatheris image at Glades Herp. Accessed 9 August 2007.
