Arthroleptis adelphus Perret, 1966 Photo figures 3A–C

TYPE LOCALITY.— “Foulassi”, near Sangmelima, Cameroon .

DISTRIBUTION.– This species ranges over the forests of the Gulf of Guinea region, from southern Cameroon to Gabon. In Equatorial Guinea, A. adelphus has been recorded in Río Muni, at Monte Alén National Park (De la Riva 1994), and on Bioko at Pico Basilé (Blackburn 2008) (Map 2A).

COMMENTS.— Our identifications of the preserved A. adelphus are confirmed by molecular data (authors’ unpublished data). Two preserved specimens (MNCN 48825–48826) from Batete, Bioko, have a striped pattern. The external morphology of this species is similar to that of members of the A. poecilonotus species complex (see entry for A. aff. poecilonotus), and a close relationship has been evidenced by molecular data (Blackburn 2008). However, in life, A. adelphus can be diagnosable by the presence of marked and larger skin granules over the dorsal and lateral parts of the body, whereas in A. poecilonotus the dorsal surface of the skin is smoother and homogenously granulated. Additional subtle differences such as the metatarsal tubercle and the subarticular tubercle of Finger I seem to be diagnostic (Dewynter et al. 2018).

SPECIMENS EXAMINED.— Nine specimens. Illadji River, Bioko, 03°19ʹ46.04ʺN, 08°40ʹ26.13ʺE, 14 November 2003 (MNCN 48833) ; surroundings of BBPP camp, Caldera de Luba, Bioko, 03°20ʹ47.32ʺN, 08°29ʹ48.44ʺE, 26 November 2003 (MNCN 48827–48828, MNCN 48830, 48832), 27 November 2003 (MNCN 48829, 48831) ; path behind church in Bakelele forest, Batete, Bioko, 03°26ʹ37.34ʺN, 08°30ʹ24.76ʺE; 02 November 2003 (MNCN 48825–48826) .