Afrixalus delicatus Pickersgill, 1984
Original Published Description:
Pickersgill's Banana Frog (English), Delicate Spiny Reed Frog (English), Delicate Leaf-folding Frog (English)
A. delicatus is distributed along the coastal plain of Mozambique (Pickersgill 1984; Poynton and Broadley 1987), and is also known to occur in southern Malawi, ranging northward along the East African coast to southern Somalia (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
This species is named for the Latin 'delicatus" meaning delicate or dainty.
This species is referred to as Afrixalus brachycnemis in Channing and Howell (2006).
This is a small slender frog with a silvery or yellow dorsum. Small dark tipped spines cover the heads of the females and the heads and backs of males. A dark band with light spots runs along each side from the snout to the groin. The dorsal pattern is variable across the species range, but in the Eastern Arc and Coastal Forests there is usually a pair of dorsolateral stripes from the vent to a patch behind the eyes. The legs are pale with dark bands. Toe tips are yellow with expanded disks. In males the throat is yellow. Females have white throats (Text from Harper et al., 2010).
Snout-vent lengths of males are up to 25 mm and females are up to 27 mm (Harper et al., 2010).
This species is syntopic with A. s. spinifrons at many localities where the ranges of these two species overlap (M.P. pers. obs.). A. delicatus is also similar, morphologically, to A. aureus, and is sympatric with that species over part of its range. However, the latter seems to prefer drier habitat and does not usually utilize the same breeding sites (Pickersgill 1984; M.P. pers. obs.). Also, the advertisement call of A. aureus lacks a “zip” component and cannot be confused with A. delicates (Modified from Minter et al., 2004, © SI/MAB Biodiversity Program).
This species is referred to as Afrixalus brachycnemis in Channing and Howell (2006). A. delicatus and A. stuhlmanni are the two dwarf Afrixalus species that occur in the coastal lowland savannas. A. stuhlmanni has a similar dorsal pattern but lacks the patch behind the eyes (Text from Harper et al., 2010).
Habitat and Ecology
A mosaic of forest patches, evergreen thicket and secondary woody vegetation set in a grassy matrix. A. delicatus is found at an altitude of 300 m the habitat has an annual rainfall exceeding 1000 mm and with an abundance of surface water that collects in a variety of natural wetlands and artificial impoundments (Modified from Minter et al., 2004, © SI/MAB Biodiversity Program).
This species is usually found in near permanent waters within savanna, shrubland and grasslands at elevations up to 500 m (Harper et al., 2010).
A.delicatus is believed to feed largely on mosquitoes (Wager 1965) and other small insects. The predators of this species are unknown (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
The mating pair move a distance of 20-150 cm after amplexus at the call site so the female can lay the eggs. During oviposition these frogs construct nests. Eggs are laid on the leaf of either a Polygonum pulchrum or Ludwedegia stolonifer. Using their hind legs the frogs bring the leaf margins together by gluing (using the adhesive oviducal secretion) the opposing leaf faces (Backwell and Passmore, 1990).
Breeding takes place during September–February. Breeding sites include permanent bodies of water such as ponds, vleis and marshes, particularly those with emergent vegetation that includes Polygonum pulchrum and Ludwigia stolonifera used during oviposition (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
Males call from vegetation at the edges of permanent water. Eggs are laid on vegetation (Text from Harper et al., 2010).
Males congregate on emergent vegetation at their breeding sites in the evening and call, calling activity is more subdued after midnight or once most of the males have paired. In South Africa, calling males within a chorus form groups of about eight individuals (Backwell and Passmore 1991), with about 25% of males that are satellites (Backwell 1991). In Kenya, choruses consist of many hundreds of males (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).
The call was described by Pickersgill (2007) as “a prolonged rattle.”
IUCN Red List Category and Justification of Conservation Status
A. delicatus is considered to be of least concern occurs in a number of reserves (Text from Minter et al., 2004, © SI/MAB Biodiversity Program).