Hyperolius mosaicus Perret, 1959

Lötters, S., Schick, S., Scheelke, K., Teege, P., Kosuch, J., Rotich, D. & Veith, M., 2004, Bio-sketches and partitioning of sympatric reed frogs, genus Hyperolius (Amphibia; Hyperoliidae), in two humid tropical African forest regions, Journal of Natural History 38 (15), pp. 1969-1997 : 1972-1973

Hyperolius mosaicus Perret

(figure 1)

This reed frog is known from forest in southern Cameroon and the Monts Cristal in Gabon ( Perret, 1966; Frétey and Blanc, 2000; Lötters et al., 2001). From the intervening area, no records are available (e.g. De la Riva, 1994). In the past there has been some taxonomic confusion between this species and the similar H. acutirostris Buchholz and Peters , from Cameroon (cf. Perret, 1966), but the two species are well distinguishable (see below). Our specimens from Gabon closely coincide with the types (cf. Lötters et al., 2001).

Diagnosis. (1) SVL of males 24.0¡ 0.76 mm (23.1–24.5 mm, n ~3), SVL of females unknown (most probably slightly larger than males); (2) TIBL/SVL 0.50¡0.01 (0.49–0.50, n ~3), HW/SVL 0.34¡0.01 (0.33–0.34, n ~3); (3) dorsal surface with small scattered warts; (4) snout shape dorsally and laterally rounded, nares visible from above; (5) E-N/EYE 0.97¡0.1 (0.9–1.1, n ~3), canthus rostralis straight from tip of snout to nostril and concave from nostril to eye; (6) tympanum distinct, TYMP/EYE 0.43¡0.08 (0.4–0.5, n ~3); (7) FOOT/TIBL 0.8¡0.04 (0.8–0.9, n ~3); (8) foot webbing formula: 1(1), 2i(1) 2e(K), 3i(1K–2) 3e(1), 4i(1K–2) 4e(1), 5(0–K); (9) PhJ is dorsally brown with up to seven light brown areas (i.e. at snout, at shoulders, on mid-dorsum and on posterior back), usually with tiny white spots, ventrally yellowish with black areas, sole and palm black with yellow toe and finger tips; females were not found but in Cameroon PhF is similar to PhJ ( Schiøtz, 1999); the gular flap of males is yellowish; the iris is reddish brown (information provided is based on collected and some non-collected males); (10) for sequence of 560 bp fragment of mitochondrial DNA of the 16S ribosomal gene see GenBank under AY323923 (~ZFMK 73140); (11) LTRF unknown for material from Gabon; Cameroonian tadpoles have 1/3 (1) (cf. Perret, 1959: 720).

Similar species are the partly sympatric H. acutirostris and H. endjami Amiet from Cameroon ( Perret, 1975; Amiet, 1980; Schiøtz, 1999). The former always has a light band in front of the urostyle and the gular flap in adult males is comparatively smaller. Hyperolius endjami lacks white dorsal tubercles and adult males have, in relation, a larger gular flap.

Life history. This species is nocturnal and arboreal. At the Monts Cristal, calling males were observed after sunset on vegetation below 1 m above ground in a semi-cleared area within the forest. This site was far away from open waters but single large trees were around. According to Perret (1959), H. mosaicus , in Cameroon, breeds in tree holes. We expect the same in Gabon and that therefore H. mosaicus may be a prolonged breeder.

The advertisement call (figure 2A; table 1) is a short ‘click’ consisting of a single pulsed note, very similar to what we know from Cameroonian specimens (cf. Amiet in Schiøtz, 1999).