Hyperolius lateralis Laurent, 1940

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 : 1989-1990

Hyperolius lateralis Laurent

(figure 9)

This reed frog is known to range from north-western Tanzania to the eastern Democratic Republic of Congo and to western Kenya; it occurs in bush land and forest ( Schiøtz, 1975, 1999). Several subspecies from Rwanda, Burundi and western Uganda were named by Laurent (e.g. 1951). According to Schiøtz (1975, 1999), they seem to reflect variation among populations of a single taxon only. We examined the female holotypes of the forms capnodogaster, pulcherrimus and subolivaceus and have the impression that they could represent distinct taxa. Comprehensive investigation remains to be carried out including also the similar H. castaneus Ahl and its junior synonyms (from eastern Democratic Republic of Congo, Rwanda and western Uganda). Kenyan material is referable to the nominotypical form and well coincides with the female holotype ( SVL 25.0 mm).

Diagnosis. SVL males 23.6¡ 0.62 mm (22.5–24.2 mm, n ~7); according to Schiøtz (1975: 129), SVL of one female 25.0 mm (a non-collected female had SVL 24.3 mm); (2) TIBL / SVL 0.47¡0.01 (0.46–0.49, n ~7), HW/ SVL 0.32¡0.02 (0.3–0.35, n ~7); (3) dorsal surface finely coarse, tuberculate below eye and tympanic area; (4) snout shape dorsally and laterally rounded, nares visible from above; (5) E-N/EYE 0.68¡0.08 (0.58–0.76, n ~7), canthus rostralis straight from tip of snout to nostril and concave from nostril to eye; (6) tympanum distinct or covered by thick skin, TYMP /EYE 0.31–0.36 (n ~2); (7) FOOT / TIBL 0.86¡0.03 (0.85–0.92, n ~7); (8) foot webbing formula: 1(K–1), 2i(1) 2e(K), 3i(1) 3e(K), 4i(1) 4e(1), 5(K); (9) PhJ and PhF are dorsally olive, brownish or yellowish green, with or without diffuse dark brown and/or bright yellow spotting, sometimes with a faint, thin light dorsolateral stripe, and in PhF a cream and/or bright yellow irregular lateral line or lateral marbling from below or behind eye to groin which always is bordered by dark brown; a dark brown canthal line may be present, ventral sides are translucent pink to reddish including sole and palm, webbing as well as parts of the upper sides of toes and fingers; the gular flap of males is dark yellowish golden; the iris is light brownish grey (information provided is based on collected and numerous non-collected specimens of both sexes); (10) for sequence of 560 bp fragment of mitochondrial DNA of the 16S ribosomal gene see GenBank under AY323924 (~ NMK A/3925/1); (11) LTRF 1/3.

Hyperolius lateralis is similar to H. cinnamomeoventris and H. castaneus , which are both sympatric in part. According to Schiøtz (1975, 1999), the latter is very variable and can be indistinguishable from H. lateralis PhJ ( H. castaneus does not fall into PhJ and PhF). It seems that a dark canthal line is always present in H. castaneus (versus occasionally present in H. lateralis ). For differentiation from H. cf. cinnamomeoventris see below.

Life history. As elsewhere, in the Kakamega Forest, H. lateralis is a nocturnal arboreal species. We observed it between April and June only. Males and females were found in disturbed primary forest, and at its edge in swampy areas or at ponds where males called from vegetation v 1.5 m above ground. This reed frog tends to be intermediate between explosive and prolonged breeding strategies. Two clutches were fixed to vegetation above the water surface, containing 94 and 179 eggs (half black, half cream) each ca 1.6–1.9 mm in diameter (without jelly). Larvae are lentic and omnivorous .

The advertisement of this species can be described as a ‘squashed peep’. It consists of a single note. Graphic and numerical characteristics (figure 2G; table 1) are comparable to data provided by Schiøtz (1975). However, frequency range and dominant frequency are somewhat higher, with overlap.