Albertine Rift Reed Frog

A large Hyperolius (males 29–33 mm) from montane forests in central Africa. Dorsum uniform brownish to orange, uniform or with diffuse dark spots. A dark canthal line. Vocal sac in calling males bright green. Ventrum bright orange. Pupil horizontal (Schiøtz 1999).Hyperolius discodactylus was split from a similar species, Hyperolius alticola. When they were differentiated as separate species, it was for a myriad of reasons, on of them being differences in species among morphological traits such as the interorbital space, tympanum, toe webbing, tibia length, subarticular tubercle, and skin of belly. For the space between its eyes, the difference is in width were that H. discodactylus is two times the width of the top eyelid while H. alticola is 1.5 times as wide as the top eyelid. The tympanum on H. alticola is smaller and free verses hidden under a thin layer of skin on H. discodactylus. The bellies of these species differ in that H. discodactylus has clear postpectoral folds while H. alticola does not. The same is seen with the temporofemoral fold between species. The other morphological differences are in length with slight noticeable variation (Liedtke et al. 2014).In preservative (ethanol): This species dorsum and posterior area below the ribs of this species are a brownish white coloration with darker peppered pigmentation forming a canthal line along its body. Its ventral coloration is a uniform pale yellow (Liedtke et al. 2014).The specimens described here were very similar to H. frontalis collected nearby (Schiøtz 1999). Initially they were described as H. alticola, but H. discodactylus has priority as the name (Schiøtz 1999; Frost 2007). However, the recent rediscovery of H. alticola has led to the split of the two species again (Liedtke et al. 2014).The two species of reed frogs were first discovered by Ernst Ahl in 1931. He found these species inhibiting the forests of the Albertine Rift in Eastern Africa. The two were synonymized by Raymond Green two decades later but a conclusive decision on this taxonomy was never made because the type material for H. alticola was lost. After the material was recently rediscovered, the validity of Laurent’s synonymy has been under reassessment. Genetic findings suggest a Northern and Southern clade and diverging morphologies also suggest a split between species. Though genetic and morphological differences are marginal, they reflect population level variation thus further supporting the continuation of H. discodactylus and the discontinuation of H. alticola is a valid taxon (Liedtke et al. 2014).The majority of this account was taken from "Treefrogs of Africa" by Arne Schiøtz with kind permission from Edition Chimaira publishers, Frankfurt am Main.The species authority is: Ahl, E. (1931b) Zur Systematik der afrikanischen Artes der Baumfrochgattung Hyperolius. Mitteilungen aus dem Zoologischen Museum in Berlin, 17 (1), 1–132.

Found in high-elevation montane forest along streams in western Rwanda, western Burundi, southwestern Uganda, and eastern D. R. Congo (Channing and Howell 2006).

The call is a rather long buzzing with a duration of about 0.3 sec and a frequency-intensity maximum at about 2000–2500 cps (Schiøtz 1999).

Although the species was initially listed as "Vulnerable", it is now considered "Least Concern". Threats to this species include agriculture, aquaculture, biological resource use, logging, small holder farming, ranching, and grazing. It also lives in a highly fragmented habitat (IUCN SSC 2013).

Very little is known about Hyperolius discodactylus or indeed about most of the species within the genus. In the wet season the reed frogs tend to gather near water, preferably smaller temporary water bodies, where they breed. However, very little is known of their whereabouts outside the breeding season (6). Most, if not all, Hyperolius species from forest habitats deposit eggs in a gelatinous mass on vegetation above water, while some savanna-living species lay their eggs aquatically (5) (6).

There are no known conservation measures for Hyperolius discodactylus, but it is known to be present in at least three protected areas, Bwindi National Park and Ruwenzori Mountains National Park in Uganda, and Virungas National Park in the Democratic Republic of Congo (1).

Hyperolius discodactylus is one of at least nine Hyperolius species endemic to the Albertine Rift, one of the richest sites for biodiversity in Africa (1) (3). In common with many species within this genus, it has moderately long-limbs and large toe pads that aid its largely arboreal lifestyle (4) (5). The smooth back of this species varies in colour between brown and orange and is sometimes dotted with diffuse dark spots. Underneath it is bright orange except for the male vocal sac which is bright green (2). The call of male Hyperolius discodactylus is a fairly long buzzing (2).

Hyperolius discodactylus occurs along streams in montane forests (6).

Found in the Albertine Rift, encompassing parts of eastern Democratic Republic of Congo, western Rwanda, western Burundi, and south-western Uganda (1).

Classified as Vulnerable (VU) on the IUCN Red List (1).

In common with other reed frogs endemic to the Albertine Rift, the distribution of Hyperolius discodactylus is severely fragmented and its population is probably declining because of a decrease in the quality and extent of its habitat. Wood extraction, habitat conversion for agriculture and encroaching human settlement are thought to be principally responsible for habitat degradation in the Albertine Rift (1).

Hyperolius discodactylus is a species of frogs in the family Hyperoliidae. It occurs in the montane areas of eastern Democratic Republic of the Congo and western Uganda, Rwanda, and Burundi. It is also known as the Albertine Rift reed frog, highland reed frog, or disc-fingered reed frog.