Comprehensive DescriptionRead full entry
A member of the Mantidactylus boulengeri-group, which contains M. boulengeri, M. boulengeri "leucocephalus", M. decaryi, M. eiselti, M. thelenae, M. klemmeri and M. webbi. This group is composed of rather small species (20-35 mm). Lateral metatarsalia are connected. An outer metatarsal tubercle is present, with the exception ofM. webbi. Webbing is absent between the fingers and reduced between the toes, except for M. webbi, in which the feet are moderately webbed. Nostrils are situated nearer to the tip of the snout than the eye. Males have paired subgular vocals sacs which are white in M. webbi and dark in the other species. Femoral glands are distinct in males, absent in females. These frogs are active and call mainly during the day. M. webbi and M. klemmeri live on mossy stones along brooks; calling males of the other species do not aggregate around water. Direct development has been observed in M. eiselti. On the lip, alternating light and dark transverse bands are present, as in the subgenus Brygoomantis, whose species are also mainly terrestrial with at least partial diurnal activity. Representatives can be distinguished from most other species of Mantidactylus by the paired subgular vocal sacs of males, only also present in the M. granulatus-group, which is composed of larger and mainly nocturnal species (references 97 and 252; for references in text see Comments, below).
Mantidactylus webbi (GRANDISON, 1953) is a medium-sized greenish species of Mantidactylus; males 22-28 mm, females 28-33 mm. Dorsal colouration similar to mossy stones: greenish with irregular dark spots, and two or three dark transverse bands. Ventral surface whitish, less pigmented. Throat with some dark colour. Hind legs with dark bands. The omosternum not distinctly forked. Skin finely granular. Tympanum distinct, about 2/5-1/2 of eye diameter. Tibiotarsal articulation reaches at least the nostrils. Lateral metatarsalia connected. Hands without webbing; webbing of the foot 1(1), 2i(1), 2e(1), 3i(2), 3e(1-2), 4i/e(2.5-3), 5(2). Males with white (!), paired subgular vocal sacs and femoral glands.
Similar species: So far as known, M. webbi is the only Malagasy frog with white, paired subgular vocal sacs. The most similar species is M. klemmeri.
Taken with permission from Glaw and Vences (2007).