Phrynobatrachus ukingensis (Loveridge, 1932)
Original Published Description:
Ukinga River Frog (English), Ukinga Puddle Frog
Phrynobatrachus ukingensis is a small species (SVL < 21 mm) of puddle frog found in the mountains of Tanzania and Malawi. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. Phrynobatrachus ukingensis is characterized by a hidden tympanum, small but distinct digital discs, and rudimentary pedal webbing. Males exhibit a black throat, and a vocal sac that forms a posterior fold when deflated.
This species occurs in eastern Tanzania (Uluguru Mountains), southern Tanzania (Ukinga and Rungwe Mountains), in northern Malawi (Misuku Mountains and at Nchenachena), and in southern Malawi (highlands south-west of Zomba at Maroka). It presumably occurs more widely, in particular between the currently known sites (Mazibuko and Poynton, 2004).
This species was named for the Ukinga Mountains in southern Tanzania.
Zimkus and Schick (2010) found that P. ungujae may be synonymous with P. ukingensis, but additional specimens of both taxa are needed.
Phrynobatrachus ukingensis is a small species (SVL < 21 mm) that is characterized by a hidden tympanum, small but distinct digital discs, and rudimentary pedal webbing. Males exhibit a black throat, and a vocal sac that forms a posterior fold when deflated.
The holotype, a female, measured 18 mm (Loveridge, 1932). Channing and Howell (2006) report that males reach 19 mm and females are only slightly larger, reaching up to 21 mm.
Tongue with a conical papilla present in the middle. Snout is moderate, much longer than the horizontal diameter of the eye. The nostril much close to the snout tip than the eye. The interorbital space is much broader than an upper eyelid. The tympanum is hidden. Tips of fingers and toes are dilated into small but distinct discs, although Loveridge (1932) notes that this is more apparent in live animals than that preserved specimen, which have had some shrinkage of the discs due to frequent removal from alcohol. Poynton and Broadley (1985) also note that circummarginal grooves are weak or absent on the toes.The first finger is shorter than the second, which is shorter than the fourth, and the third is by far the longest. Two metatarsal tubercles (inner and outer), as well as a tarsal tubercle are present. Toes are rudimentary with the four phalanges free of webbing on toe IV, three phalanges free on toes III and V, and two phalanges free on toe I and II. Zimkus (unpublished) examined specimens with 3-4 phalanges free on toe IV. The tibio-tarsal articulation of the adpressed hind limb reaches the eye. The skin of the back is smooth with inconspicuous flattened warts (Loveridge, 1932). Dorsal skin glands are weakly developed. Glands are also present on the upper leg. When the male's vocal sac is deflated, it often forms a tranverse fold (Poynton and Broadley, 1985).
Dorsum is mainly brown or olive, minutely mottled with dusky brown. A light vertebral line may be present from snout to anus with similar lines on thighs and tibiae. Barring may present on the upper and lower jaws (Poynton and Broadley, 1985). A continuous light subtympanic band, extending from the lower eyelid to the base of the arm, is present, typically bordered by an irregular dark band. The venter is largely transparent posteriorly. In females, the throat presents dusky specklings or freckling, which may extend to the breast well between the forearms. In males, the throat is dusky to black in color, and a patch is present across the belly at midbody, which is cream colored with a satiny gloss (Loveridge, 1932).
This species is distinguished from many other small East African puddle frogs by the presence of digital discs; Phrynobatrachus inexpectatus, P. mababiensis (including its junior synonyms P. vanrooyeni, P. chitialaensis, P. broomi), P. minutus, P. parvulus (including its junior synonyms P. schoutedeni, P. ukingensis nyikae) and the P. kakamikro are all similar in size but do not exhibit expanded toe tips. The foot of P. kinangopensis and P. perpalmatus is well webbed, distinguishing it from this species. Phrynobatrachus rungwensis, P. ungujae, and P. uzungwensis exhibit well-developed digital discs and an indistinct tympanum. Phrynobatrachus ungujae differs by its smaller size (snout–vent length < 16 mm). Phrynobatrachus rungwensis does not exhibit a light subtympanic band, and males have grey throats. Phrynobatrachus uzungwensis differs by its extensive pedal webbing, and the gular region in males is yellow. Phrynobatrachus breviceps and P. stewartae also exhibit more extensive pedal webbing (at maximum two and a half phalanges of fourth toe free of webbing).
Habitat and Ecology
It is a montane species, probably occurring above 1,000m asl, and perhaps ranging to over 2,000m asl in places. It is found in forest, forest edges, and open montane grassland. It may live in marshy areas in open habitats, or at the edges montane forest. (Mazibuko and Poynton, 2004).
Males call while hidden in the base of grasses near pools and other small bodies of water. This species breeds in the summer, although males do call during most months of the year. Egss are black in color and small (0.9 mm in diameter within 1.1 mm capsules). They are laid in a single layer, approximately 50 mm across, that floats on the surface of the water (Channing and Howell, 2006).
The call is made up of a number of long buzzes (pulse rate of 80/s and an emphasized frequency of 4.1 kHz) that are interspersed with clicks (Channing and Howell, 2006).
Evolution and Systematics
Zimkus and Schick (2010) found that P. ungujae may be synonymous with P. ukingensis, which is not surprising given that this species was often confused with P. ukingensis prior to its description (Pickersgill, 2007). This result was confirmed in an phylogenetic analyis of the genus by Zimkus et al. (2010). Further investigation, including additional genetic samples of both species, is needed.
IUCN Red List Category and Justification of Conservation Status
The IUCN Red List (2009) categorizes this species as Data Deficient in view of continuing doubts as to its taxonomic validity, extent of occurrence, status and ecological requirements (Mazibuko and Poynton, 2004).
The main threats to this species are agricultural expansion, wood extraction and expanding human settlements, which are most likely adversely affecting it by causing the ongoing loss of forest and degradation of montane grassland within its range (Mazibuko and Poynton, 2004).
Conservation Actions and Management
This species occurs in Matipa Forest Reserve in the Misuku Mountains of Malawi (Mazibuko and Poynton, 2004).
- Arthroleptis ukingensis Loveridge, 1932 (synonym)
- Phrynobatrachus ukingensis — Laurent, 1941 (synonym)
- Phrynobatrachus ukingensis ukingensis — Loveridge, 1953 (synonym)