Second record of the West African hairy bush viper Atheris hirsuta Ernst & Rödel, 2002 (Serpentes: Viperidae).

The African bush vipers of the genus Atheris Cope, 1862 currently comprises 15 species, this includes A. barbouri Loveridge, 1930 (often assigned to the genus Adenorhinos; but see Lenk et al. 2001). All species occur exclusively on the African continent with most species occurring in East and Central Africa. West Africa, defined as the eco-region including Nigeria and all countries westwards, excluding Cameroon (see Penner et al. 2011), currently harbours three species of Atheris. (i) Atheris squamigera (Hallowell, 1854) which has a wide range across Central Africa and can be found in south-eastern Nigeria (Spawls & Branch 1995; Luiselli et al. 2000). However, the taxonomy of central African Atheris is still under debate and several hidden species might be included (see Broadley 1998; Lawson 1999; Lawson & Ustach 2000; Lawson et al. 2001). Concerning distribution,we follow Chippaux (2006) and others in regarding all records of A. squamigera west of Nigeria as doubtful. A true West African species is (ii) Atheris chlorechis (Pel, 1851) which ranges from Guinea, through Sierra Leone, Liberia, Côte d’Ivoire and Ghana to Togo. Its occurrence in Nigeria is unclear. So far no records exist for Benin (Ullenbruch et al. 2010; Hughes 2013; C. Toudonou pers. comm.). The third species, (iii) Atheris hirsuta Ernst & Rödel, 2002, was described from a single specimen found near the ecological research station in the Taï National Park, Côte d’Ivoire. No further records existed until this study. A short survey of the herpetofauna of Mt. Swa in Nimba County, Liberia (approximately 200km west of the type locality) revealed the second specimen of this species (leg. & det. J. Penner). The mountain does harbour good secondary forests and altitude remains below 600m a.s.l. The specimen was found around 9pm on the 26 of September 2012. The individual was observed climbing through secondary vegetation in ca. 2m height on the ridge of the mountain (585m a.s.l.). No water bodies of any kind were found on top of the ridge. Weather was windy, cloudy but without rain. Colouration and morphology of the specimen clearly resembles that of the holotype (see Fig. 1, Tab. 1, 2 & 3). The specimen was collected, photographed on the following morning and then killed with an overdose of 20% benzocaine solution. Muscle tissue was taken from the ribs between the anterior two thirds and the posterior one third of the body (stored in 96% Ethanol, for genetic analysis). The specimen was fixed in formaldehyde (4%) with everted hemipenes and later transferred to ethanol (70%). It is now stored in the herpetological collection of the Museum für Naturkunde, Berlin (ZMB 78827).