Conraua alleni ( Barbour and Loveridge, 1927 )

Kanga, Kouassi Philippe, Kouamé, N’Goran Germain, Zogbassé, Parfait, Gongomin, Basseu Aude-Inès, Agoh, Konan Laurent, Kouamé, Akoua Michèle, Konan, Jean Christophe B. Y. N., Adepo-Gourène, Abouo Béatrice, Gourène, Germain & Rödel, Mark-Oliver, 2021, Amphibian diversity of a West African biodiversity hotspot: an assessment and commented checklist of the batrachofauna of the Ivorian part of the Nimba Mountains, Amphibian & Reptile Conservation (e 275) 15 (1), pp. 71-107 : 81

Conraua alleni ( Barbour and Loveridge, 1927)

Allen’s Giant Frog

Material: Two unsexed, NGK-Nimba 0057 ( Fig. 8A ), NGK-Nimba 0058 , and two females, NGK-Nimba 0059 ( Fig. 8B ), NGK-Nimba 0073 .

Comments: Conraua alleni is a highly aquatic frog, which inhabits slow- to fast-flowing forest streams, from lowlands to montane forest areas. Records are known from eastern Guinea and Sierra Leone, through Liberia to western Ivory Coast, with an isolated population occurring in western Ghana ( Barbour and Loveridge 1927; Guibé and Lamotte 1958a; Lamotte and Perret 1968; Rödel 2003; Rödel and Bangoura 2004; Channing and Rödel 2019; Rödel and Glos 2019; Schäfer et al. 2019). Some of these populations may comprise cryptic taxa (see Rödel and Branch 2002; Hillers et al. 2008a). We found C. alleni populations in streams intersecting forest patches (07°35.258’N, 008°25.052’W; 821 m asl). Other individuals were heard calling in a very impressive torrent stream in mid-elevation forest (07°34.652’N, 008°24.966’W; 716 m asl). The bird-like whistles were heard during day and night, with peaks after sunset (around 1841 h GMT). Additional populations were found at night in pools of a slow running stream with a sandy and rocky bottom. This stream crossed a slightly degraded forest patch dominated by bamboo (07°32.993’N, 008°24.753’W; 425 m asl), where a total of 14 adult frogs were caught. Through palpation of the lower abdomen, two of them were identified as gravid females. Their body size was 52.8–54.0 mm. The remaining 12 frogs ranged from 51.1–55.6 mm but could not be sexed. One adult, kept in captivity for two months, preyed on locusts, ants, spiders, caterpillars, and butterflies that were floating on the water surface. All adult C. alleni had a clear interorbital line, however, their back pattern varied from a darker brown with black dots and reddish legs to frogs with orange patches on the darker brown ground. In contrast to other described C. alleni (e.g., Channing and Rödel 2019), the venter of our frogs was golden yellow or beige to pinkish, and the thighs had a pink ventral color. The throat was dark, and pinkish with reddish-brown dots or uniform beige. The taxonomic status of these frogs and the populations from nearby Mount Sangbé National Park (Rödel 2003) should be investigated.

Figures

Fig. 8. Conrauid, dicroglossid, hemisotid, and hyperoliids from Mount Nimba Integrated Nature Reserve: Conraua alleni (A–B); Hoplobatrachus occipitalis (C); Hemisus marmoratus (D); Afrixalus dorsalis (E); A. fulvovittatus (F); Hyperolius chlorosteus (G–H).