Causus bilineatus

Causus bilineatus
Conservation status
	; Least Concern (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Viperidae
Genus:	Causus
Species:	C. bilineatus
Binomial name
	Causus bilineatus; Boulenger, 1905
Synonyms
	Causus rhombeatus ; — Bocage, 1895 (part); Causus rhombeatus var. bilineatus ; Boulenger, 1905; Causus lineatus ; Laurent, 1955; Causus bilineatus bilineatus — Laurent, 1964; Causus bilineatus ; — Broadley, 1971;

Causus bilineatus is a species of venomous snake in the subfamily Viperinae of the family Viperidae. The species is native to southcentral Africa.^[3] There are no subspecies that are recognized as being valid.^[4]^[5]

Common names

Common names for C. bilineatus include lined night adder,^[3] two-lined night adder,^[4] and two-striped night adder.^[4]^[6]

Description

Adults of C. bilineatus have an average total length (tail included) of 30–50 cm (12–20 in), with a reported maximum of 65 cm (26 in).^[3]

The head is slightly distinct from the neck, while the snout is fairly long and tapering. Midbody there are 15–18 rows of dorsal scales that are weakly keeled and have a soft and velvety appearance. The ventral scales number 122–141 in males and 128–144 in females. There are 18–30 subcaudals.^[3]

The color pattern consists of an ash to auburn to brown ground color, overlaid with numerous irregular or vaguely rectangular black dorsal patches. These patches lie within two distinct and narrow pale stripes that run the length of the body. The belly color is dark to dark cream.^[3]

Geographic range

C. bilineatus is found in Angola, southern DR Congo, Rwanda, western Tanzania, and Zambia.^[4]

The type locality is given by Boulenger (1905) as "between Benguella and Bihé" (Angola). Bocage (1895) listed "Duque de Bragança, Quissange, Caconda, and Huilla" (Angola) for the localities.^[2]

Habitat

C. bilineatus occurs in moist savanna, forest-savanna environments, and swampy habitats,^[3] at altitudes of 800–1,800 m (2,600–5,900 ft).^[1] Wild-caught specimens found to have eaten clawed frogs, Xenopus, suggest a more aquatic nature than other species.^[3]

Diet

C. bilineatus preys mostly upon toads and frogs, particularly the frogs of the genus Xenopus.^[3]

Reproduction

C. bilineatus is oviparous.^[1]^[4]

Venom

C. bilineatus is venomous, and there is no available antivenom. However, no human fatalities from its bite have been recorded.^[7]

References

^ ^a ^b ^c Wagner P (2021). "Causus bilineatus ". IUCN Red List of Threatened Species. 2021: e.T13300996A13300998. doi:10.2305/IUCN.UK.2021-3.RLTS.T13300996A13300998.en. Retrieved 25 January 2025.
^ ^a ^b McDiarmid RW, Campbell JA, Touré TA (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
^ ^a ^b ^c ^d ^e ^f ^g ^h Mallow D, Ludwig D, Nilson G (2003). True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. 359 pp. ISBN 0-89464-877-2.
^ ^a ^b ^c ^d ^e Causus bilineatus at the Reptarium.cz Reptile Database. Accessed 20 June 2021.
^ "Causus bilineatus". Integrated Taxonomic Information System. Retrieved 20 June 2021.
^ Spawls, Stephen; Branch, Bill (1995). The Dangerous Snakes of Africa. Dubai: Oriental Press / Ralph Curtis Books. 192 pp. ISBN 0-88359-029-8.
^ Spawls S, Howell K, Hinkel H, Menegon M (2018). A Field Guide to East African Reptiles, Second Edition. London: Bloomsbury Wildlife. 624 pp. ISBN 978-1-399-40481-5. (Causus bilineatus, p. 569).