Xenocalamus bicolor, or the slender quill-snouted snake, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of venomous rear-fanged snake

Snake

Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...

 in the family Atractaspididae

Atractaspididae

The Atractaspididae are a family of snakes found in Africa and the Middle East. Currently, 12 genera are recognized.-Description:This family includes many genera formerly classed in other families, on the basis of fang type. It includes fangless , rear-fanged , fixed-fanged , and viper-like species...

. It is endemic to Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

.

Geographic range

It is found in 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...

, Botswana

Botswana

Botswana, officially the Republic of Botswana , is a landlocked country located in Southern Africa. The citizens are referred to as "Batswana" . Formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966...

, Democratic Republic of the 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...

, 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...

, Namibia

Namibia

Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

, Republic of South Africa, and Zimbabwe

Zimbabwe

Zimbabwe is a landlocked country located in the southern part of the African continent, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest and Mozambique to the east. Zimbabwe has three...

.

Description

Black dorsally. White ventrally including the upper lip and the first two rows of dorsal scales on each side.

Total length 43 cm (16⅞ inches); tail 3 cm (1⅛ inch).

Dorsal scales smooth, without apical pits, arranged in 17 rows. Ventrals 218; anal plate divided; subcaudals 24, also divided.

Portion of rostral visible from above nearly half as long as the frontal. Frontal extremely large, more than half as long as the shielded part of the head. Internasals large, forming a short median suture. Supraocular very narrow. One large elongate preocular, contacting the posterior nasal, the internasal, the frontal, and the third upper labial. One minute postocular. One temporal. Six upper labials, the first very small, third and fourth entering the eye, the fifth very large and contacting the parietal. One pair of narrow chin shields. Three lower labials in contact with the chin shield. Third lower labial extremely large.

[Nota bene: the description above is a description of the species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 X. bicolor. The subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 listed below vary somewhat from this description.]

Subspecies

Seven subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 are recognized including the nominate race.

• Xenocalamus bicolor australis FitzSimons, 1946
• Xenocalamus bicolor bicolor Günther, 1868
• Xenocalamus bicolor concavorostralis Hoffman, 1940
• Xenocalamus bicolor lineatus Roux, 1907
• Xenocalamus bicolor machadoi Laurent, 1954
• Xenocalamus bicolor maculatus FitzSimons, 1932
• Xenocalamus bicolor pernasutus (F. 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....
  
  , 1915)