''Polemon christyi'', also known commonly as Christy's snake-eater and the eastern snake-eater, 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 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 ...

rear-fanged

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Aparallactinae The Atractaspididae (atractaspidids) are a family of venomous snakes found in Africa and the Middle East, commonly called mole vipers, stiletto snakes, or burrowing asps. Currently, 12 genera are recognized. Description This family includes many ...

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 ...

Atractaspididae The Atractaspididae (atractaspidids) are a family of venomous snakes found in Africa and the Middle East, commonly called mole vipers, stiletto snakes, or burrowing asps. Currently, 12 genera are recognized. Description This family includes many ...

. The species is native to

Central Africa Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo, ...

and

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

Etymology

The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''christyi'', is in honor of English physician

Cuthbert Christy Cuthbert Christy (1863 – 29 May 1932) was an English doctor and zoologist who undertook extensive explorations of Central Africa during the first part of the 20th century. He was known for his work on sleeping sickness, and for the Christy Repo ...

, who presented the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

to the

British Museum (Natural History) The Natural History Museum in London is a museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum an ...

. Boulenger GA (1903). "Descriptions of new Snakes in the Collection of the British Museum". ''Annals and Magazine of Natural History, Seventh Series'' 12: 350-354. (''Miodon christyi'', new species, p. 354). Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Polemon christyi'', p. 54).

Geographic range

Distribution of ''Polemon christyi'' include

Uganda }), is a landlocked country in East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territor ...

, the

Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

South Sudan South Sudan (; din, Paguot Thudän), officially the Republic of South Sudan ( din, Paankɔc Cuëny Thudän), is a landlocked country in East Africa. It is bordered by Ethiopia, Sudan, Central African Republic, Democratic Republic of the C ...

, and western

Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

. The status of observations from

Rwanda Rwanda (; rw, u Rwanda ), officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of Central Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator ...

and

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...

is uncertain, whereas observations from

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

, and possibly

Burundi Burundi (, ), officially the Republic of Burundi ( rn, Repuburika y’Uburundi ; Swahili language, Swahili: ''Jamuhuri ya Burundi''; French language, French: ''République du Burundi'' ), is a landlocked country in the Great Rift Valley at the ...

likely refer to '' Polemon ater'' described in 2019.

Habitat

The preferred natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s of ''P. christyi'' are

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

and

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

, at altitudes of .

Description

The dorsum of the body of ''P. christyi'' is black. The ventral surface of the head is also black. The

ventrals In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

and

subcaudals In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...

are white, broadly margined with black. The

, a female, is in total length, which includes a tail long. The

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

are smooth, without apical pits, and are arranged in 15 rows at midbody. The ventrals number 209. The

anal plate Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involving ...

is divided. The subcaudals number 20, also divided. The diameter of the eye is three fifths its distance from the mouth. The

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

is higher than wide, barely visible from above. The

internasals In snakes, the internasal scales are those on top of the head between the scales that surround the nostrils. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates. (7 ...

are slightly shorter than the prefrontals. The

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ...

is slightly longer than broad, much broader than the

supraoculars 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. ...

, as long as its distance from the rostral, much shorter than the parietals. The

nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery ** ...

is entire, in contact with the

preocular In scaled reptiles, the ocular scales are those forming the margin of the eye.Wright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . The name originates from the term ''oculus'' which ...

. There are two postoculars. The temporals are 1+1. There are seven

upper labials In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ( ...

, the third and fourth entering the eye. There are four

lower labials In reptiles, the sublabial scales, also called lower-labials or infralabials, are those scales that border the mouth opening along the lower jaw. They do not include the median scaleWright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publis ...

in contact with the anterior

chin shield Chin shields or chinshields, genials scales on a snake are scales found on the underside of the snake's head towards the anterior and touching the lower labial scales. Chin shields to the front of the snake (towards the snout) are called anterior c ...

, the first lower labial forming a suture with its fellow behind the

mental Mental may refer to: * of or relating to the mind Films * ''Mental'' (2012 film), an Australian comedy-drama * ''Mental'' (2016 film), a Bangladeshi romantic-action movie * ''Mental'', a 2008 documentary by Kazuhiro Soda * ''Mental'', a 2014 O ...

. There are two pairs of chin shields, the anterior pair larger than the posterior pair.

Diet

''P. christyi''

preys Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

upon snakes, including those of its own species.

Reproduction

''P. christyi'' is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...