''Proatheris'' (commonly referred to as the lowland viper and swamp viper among other names) is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

created for the

viper 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 (relative to non-vipe ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, ''Proatheris superciliaris''. This is a small

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

species

endemic Endemism is the state of a species being found only 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 foun ...

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

. Like all other vipers, it is

venomous 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 ...

. No

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

are currently recognized.

Description

''Proatheris superciliaris'' is a small species that averages 40 to 50 cm (about 16 to 20 inches) in total length (body + tail), with a maximum total length of . 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 scales In scaled reptiles, supraocular scales are (enlarged) scales on the crown immediately above the eye.Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. ...

, which are almost twice as long as they are wide.Mallow D, Ludwig D, Nilson G. 2003. ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. .

Common names

Common names for the ''Proatheris'' include the lowland viper, swamp viper,Spawls S, Branch B. 1995. ''The Dangerous Snakes of Africa''. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. . lowland swamp viper, eyebrow viper, swamp adder, Peter's viper, flood-plain viper, Mozambique viper, African lowland viper,Brown JH. 1973. ''Toxicology and Pharmacology of Venoms from Poisonous Snakes''. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. . and the domino viper.U.S. Navy. 1991. ''Poisonous Snakes of the World''. US Govt. New York: Dover Publications Inc. 203 pp. .

Geographic range

It is found in East Africa. The southern part of its range begins near Beira, in central

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

, extends up north over the Mozambique Plain to Quissanga, and through

Malawi Malawi, officially the Republic of Malawi, is a landlocked country in Southeastern Africa. It is bordered by Zambia to the west, Tanzania to the north and northeast, and Mozambique to the east, south, and southwest. Malawi spans over and ...

and as far north as the floodplains of southern

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

at the northern end of

Lake Malawi Lake Malawi, also known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, () is an African Great Lakes, African Great Lake and the southernmost lake in the East African Rift system, located between Malawi, Mozambique and Tanzania. It is ...

. The type locality given is ''"Terra Querimba"'' (= Quissanga mainland opposite Ilha Quirimba, Mozambique). Its range is apparently centered on the lower section of the

Zambezi River The Zambezi (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than half of t ...

and spreads out into the coastal plain of central Mozambique and the Shire Valley to

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. There is an isl ...

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

It is almost always found in low-lying

marsh In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in genera ...

es,

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s and land frequently used for grazing cattle. The soil is never too dry, since this would make it difficult for the

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s that they feed on to dig their burrows. These snakes are entirely terrestrial and are usually found in or around these rodent

burrow file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...

Behaviour

One of the distinguishing characteristics of the ''

Atheris ''Atheris'' is a genus of Viperinae, vipers known as bush vipers.Spawls S, William Roy Branch, Branch B (1995). ''The Dangerous Snakes of Africa''. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. . They are found only in tropical Sub-Saharan ...

'' group (to which ''Proatheris'' is closely related), is that they have

prehensile tail A prehensile tail is the tail of an animal that has Adaptation (biology), adapted to grasp or hold objects. Fully Prehensility, prehensile tails can be used to hold and manipulate objects, and in particular to aid arboreal creatures in finding and ...

s. With ''Proatheris'', the young and subadults have this capability, but it is diminished in the adults.

Feeding

Preys mainly on small

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

s and

toad Toad (also known as a hoptoad) is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands. In popular culture (folk taxonomy ...

s. Occasionally, it also feeds on small rodents.

Reproduction

This species is

viviparous In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

, with typically 3-16 neonates.

Venom

The first known case of a survivor of

snakebite 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 ...

by this species was reported by Els (1988), involving a juvenile and 24-year-old victim penetrated by a single fang. The results were painful, but there were none of the strongly

hemotoxic Haemotoxins, hemotoxins or hematotoxins are toxins that destroy red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term ''haemotoxin'' is to some degree a misnomer since toxins that damage ...

symptoms that had been associated with ''

'' venom up to that point. In a second case in 1996, a victim experienced severe

hemolysis Hemolysis or haemolysis (), also known by #Nomenclature, several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may ...

and complete

platelet Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no ...

destruction after which his liver and kidneys began to fail. When it was feared that the patient might die from hemolytic-uremic syndrome,

plasmapheresis Plasmapheresis (from the Greek language, Greek πλάσμα, ''plasma'', something molded, and ἀφαίρεσις ''aphairesis'', taking away) is the removal, treatment, and return or exchange of blood plasma or components thereof from and to the ...

was performed. Luckily, the patient survived, but it is now obvious that ''P. superciliaris'' venom is very

Taxonomy

This species was previously placed in the genus ''

'' based on skull characteristics and because of its partially prehensile tail.

Etymology

The generic name, ''Proatheris'', is

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "before-''atheris''".