Herpetology of Ethiopia and Eritrea


Hemisotidae Cope, 1867


Hemisus marmoratus (Steindachner, 1863)

Hemisus marmoratus - Gambella, Ethiopia
Hemisus marmoratus - Gambella, Ethiopia

Description:
A plump, almost cylindrical frog with a very pointed snout and short but sturdy limbs. Males measure 22–34 mm (SVL), weighing 1.3 to 5.0 g. Females bearing no eggs weigh 5.8–6.3 g, otherwise 7.7–12 g (SVL: 37–49 mm). A bulging dermal fold separates the neck and the snout regions. Males have a single subgular vocal sacs which are usually covered by a small gular flap. They have small eyes with vertically slit pupils. These frogs have no visible tympanum. Both the hardened snout and the large inner metatarsal tubercles have been transformed into digging tools. The inner metatarsal tubercle reaches 0.9–1.9 of the shortest toe length. The thighs reach 0.2–0.4, the lower legs 0.3-0.4 and the foot, including the longest toe, 0.5–0.6 of the SVL. Neither toe-tips nor finger-tips are enlarged. No traces of webbing. The skin is usually smooth, occasionally finely granular. Loveridge (1929) cites a female from Kenya with 52 mm SVL.

Distribution:
Subsaharan Africa from west to east and south in savanna areas.
Senegal, Benin, Togo, Burkina Faso, Camerun, Central African Republic, Chad, Eritrea, Ethiopia, Somalia, Kenya, Gambia, Ghana, Guinea-Bissau, Malawi, Mossambic, Nigeria, SRA, Namibia, Swaziland, Tanzania, Zambia, Zimbabwe.
In Ethiopia lowlands in the west under Ethiopian highland.

Biology:
H. marmoratus seems to be a predominantly subterranean species. Unlike most other burrowing species, which burrow by means of the metatarsal tubercles of their hind limbs (transformed into shovels), digging themselves backward rather slowly, Hemisus species invariably burrow head first, even when the male clasps his mate in inguinal amplexus. However, it is not sure whether these frogs are active or forage for prey below the surface. Although they are very likely to do so, we have not yet found evidence. H. marmoratus is encountered at the surface mainly at night, or immediately before or after rainfall when the air is saturated with humidity. This observation is confirmed by Poynton & Broadley (1985a). Otherwise, the frogs are hardly ever active at the surface. The diet nearly exclusively consists of ants and termites. Each pair will dig a burrow near the water, and the eggs are deposed in this subterranean refuge. Most probably, the males leave the burrow soon after. On the other hand, the females keep sitting on the clutch which would dry up otherwise. Eggs stuck on the back of the female. When the rains come, female smoothen the way to water and tadpoles will be moved into the water.

Description original:
Peters, W. C. H. 1854. Diagnosen neuer Batrachier, welche zusammen mit der früher (24. Juli und 18. August) gegebenen Übersicht der Schlangen und Eidechsen mitgetheilt weden. Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin 1854: 614-628.

Described as Engystoma marmoratum

Common english name: Mottled Burrowing Frog




Hemisus microscaphus Laurent, 1972      !

Hemisus microscaphus - Bedelle, Ethiopia

Description:
A small frog; size up to 50 mm. Males are smaller; on throat subgular vocal sac. Head significantly pointed, hind limbs with large foot spurs. Dorsum brown or reddish brown, with darker and yellow dots on body and limbs.
A medium-sized species of Hemisus, snout-vent length of adult males 29-35 (mean 32.7) mm, of females 36-45 (40.7) mm; limbs moderate, the tibia 36-44 (40. 7)% of snout-vent length; digits comparatively long, their tips bluntly rounded or even slightly swollen; inner metatarsal tubercle exceptionally small, its length just 30-46% that of the free portion of toe V, and not powerfully compressed; upper eyelid only 20-27% of the unusually broad interorbital space; dorsum flecked, spotted or blotched with yellow; venter more or less extensively suffused with dark pigment that encloses yellow flecks, spots or blotches on the throat, flanks and limbs, but centre of the chest and abdomen always paler than the lower flanks
Colour: Deep purplish-brown above, obscurely to distinctly marbled with greyish- or reddish-brown, although sometimes the paler pigment is expanded to form the ground colour and the darker may then become reduced to no more than sparse mottling; occasionally the back is sprinkled with few to numerous vivid yellow dots; sides of the head purplish-grey freckled with pale yellow; flanks pinkish or purplish-brown and, like the upper surfaces of the limbs, more or less prominently and profusely speckled, spotted or blotched with pale to bright yellow, this pigmentation being most intense on the hindlimbs, sometimes even appearing pale orange on the backs of the thighs. Cornified snout tip whitish to pale pink. Venter dirty yellow, suffused to a greater or less extent with pale to dark purplish- brown, especially peripherally; on the throat this dark pigment encloses profuse pale freckling, on the lower flanks pale speckles or spots, and on the underside of the hindlimbs large pale blotches which may coalesce to form coarse mottling; only occasionally is the mid-ventral area completely immaculate, more commonly it is lightly to heavily sprinkled with dark chromatophores. Mid-gular region of adult males intense purplish-brown to black [according to LARGEN].

Distribution:
This species is endemic to the highlands of southwestern and western Ethiopia. It is typically found in montane grassland at elevations between at about 1,500 and 2,700m.

Biology:
Usually it is found in a mountain meadows and pastures, but marginally extends to the tropical forests and wet savannas. There inhabits in wet and humid habitats around streams and lakes. They usually live underground, under the bark of large trees, etc. I found a piece in wet decayed trunk of a fallen sycamore tree where the frog probably hunted everywhere present termites. Eggs lays like the previous species to underground nest chambers, where tadpoles develop into a certain size, under the protection of the mother. From there, then move on to end metamorphosis into water. Tadpoles which lives in nests probably feeds by secretion from skin of females, in the water by detritus and algae. Larval development was observed in periodicals but also in permanent water.

Description original:
Laurent, R. F. 1972. Tentative revision of the genus Hemisus. Annales du Musée Royal de l'Afrique Centrale. Série in Octavo, Science Zoologique. Tervuren 194: 1-67.

Common english name: Lake Zwai Shovelnose Frog























































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