AMPHIBIAWEB
Phrynobatrachus acutirostris
family: Phrynobatrachidae
Conservation Status (definitions)
IUCN (Red List) Status Near Threatened (NT)
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Congo, the Democratic Republic of the, Rwanda

 

View distribution map using BerkeleyMapper.

   

From the Encyclopedia of Life account:

Summary

Phrynobatrachus acutirostris is a large species (SVL 37-51 mm) of puddle frog from the Albertine Rift, recorded from the Democratic Republic of Congo, Rwanda, and Burundi. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. Phrynobatrachus acutirostris is characterized by its sharp snout and the presence of digital discs, moderate pedal webbing, and a distinct tympanum. The coloration is extremely variable, but there is often a clear difference between the lighter coloration of the dorsum and the darker and tympanic region, or there may be lighter lateral band separating a dark dorsum and dark tympanic region. Ventral coloration is also variable, although always mottled, speckled or dotted, often with longitudinal band running through the throat and breast. Males exhibit minute asperities and a prominent nuptial pads is present on the base of finger I.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Etymology

From 'acuti' (Latin) meaning acute, and 'rostris' (Latin) meaning snout, this species is named for it's pointed snout.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Distribution

This very poorly known species has been recorded only from the "Lake Region" of eastern Democratic Republic of Congo, western Rwanda, and north-western Burundi (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Morphology

Aspect is raniform with a sharply pointed snout. A clearly visible conical papilla is present in the middle of the tongue. The head is approximately as long as broad, The obtusely pointed snout is rather flattened, sharply exceeding the mouth. Canthus rostralis is very angular. Loreal region is slightly concave. Nostrils are close to the tip of the snout than the eye. The interorbital space is much wider than the upper eyelid. Tympanum is distinct, measuring about 3/4 of the diameter of the eye. First finger is shorter than the 2nd, and the 3rd about 1.5 times as long as the previous one. Digit tips are dilated at their ends into small distinct discs. Manual webbing is absent. According to de Witte (1941), the toes are 3/4 webbed; Zimkus et al. (2010) finds that webbing is moderate and somewhat variable with 2-3.5 phalanges free of webbing on toe IV. Toes are also dilated into small discs. Sub-articular tubercles are moderately prominent. The inner metatarsal tubercle is ovular in shape and well developed, connected to the smaller tarsal tubercle by a raised ridge. The outer metatarsal is also less prominent and round. The internal metatarsal tubercle is located equidistant from the tarsal tubercle and outer metatarsal tubercle. According to de Witte (1941), the internal metatarsal tubercles of females seem less well developed, and there is no trace of skin fold on the inner side of tarsus. The tibio-tarsal articulation reaches the nostril, the tip of the snout or beyond when the hind limb is brought forward; Nieden (1913) did not state this in the original description regarding the female holotype. The tibia is 60% of SVL, and the tibia is 20% of the SVL. When bent at right angles to the axis of the body, tibiae strongly overlap. The head is separated into dorsal and lateral sections by a ridge that runs from the upper lip through the canthus rostralis. This line continues behind the eye as a prominent dorsolateral glandular cord, extending into the lumbar region. A 2nd fold may be present below the previous, starting behind the eye, bypassing the eardrum and extending into the shoulder region or into the sacral region, either interrupted or continuous. Glands forming an X-shape may be visible on the dorsum. The skin of males is dotted with minute asperities, especially toward the sacral region, the lateral side of the head, the lateral side of the body, the inner thighs (where they are most numerous and most developed) and the inner sides of the tibia. In females there are some asperities may be present, especially on the lateral sides of the body and in close proximity of the vent, but nothing like those of the male. According to de Witte (1941), the gular sac is absent in males; however, a single lateral vocal fold on each side of the throat of MCZ A-26503. A prominent nuptial pads is present on the base of finger I in males.

The coloration is extremely variable; dorsum brownish, reddish brown, dark brown or yellowish gray, uniform, mottled, spotted or mottled with blackish brown. There is often a clear difference between the coloration of the upper (lighter) and the lateral side of the body and head (dark brown), or there may be lighter colored lateral band separating a dark dorsum and dark tympanic region. The sides of body are blackish brown, edged sharply with the color of lighter upper parts, although in some specimens, the color is generally lighter, and this difference is not as marked. The sides of head are a uniform blackish brown. In some individuals the upper lip is lighter in color, sometimes white, more or less spotted or speckled with blackish brown. Scapular glands are often the same dark color as the dorsum, but sometimes may be outlined darker. A lighter transverse band may be present between eyes. A clear, thin vertebral line sometimes extends from the tip of the snout to anus. Anterior and posterior limbs are the same color as the body, with transverse bands of blackish brown. Ventral coloration is also variable, although always mottled, speckled or dotted and never uniform. The color may be yellowish, brownish, purplish or white. The throat is mottled and appears darker, often with longitudinal band that is the same color as the breast and belly separating it in half. This longitudinal line may also separate the chest and belly, with spots are present in both these areas, although less numerous in the latter. Region surrounding the vent is mostly dark brown. Forelegs and hind legs may be spotted, and a band of blackish brown is present, extending from the ankle along the tarsus and to part of the metatarsus.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Size

The female holotype measures 46 mm (Nieden, 1913). Males of SVL 37-46 mm (N=49), and a single females measuring 51 mm were reported by de Witte (1941). A male measuring 37.0 mm (MCZ A-26503), a female measuring 39.8 mm (MCZ A-26502), and a cleared-and-stained specimen measuring 40.0 mm (CAS-SUA 13011) were examined by B. Zimkus.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Diagnostic Description

P. acutirostris is a large-bodied species (SVL up to 51 mm) characterized by its sharp snout and the presence of digital discs, moderate webbing of the toes, and a distinct tympanum. The coloration is extremely variable, but there is often a clear difference between the lighter coloration of the dorsum and the darker and tympanic region, or there may be lighter lateral band separating a dark dorsum and dark tympanic region. Ventral coloration is also variable, although always mottled, speckled or dotted and never uniform, often with longitudinal band running through the throat and breast. Males exhibit minute asperities and a prominent nuptial pads is present on the base of finger I.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Habitat and Ecology

It is presumably a forest species as it has been recorded as occurring in forest streams. It is also presumably a montane species, but its altitudinal range is not recorded (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Population Biology

There is no information on the population status of this species (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Activity and Special Behaviors

This frog is rests alongside streams, jumping directly under the overhanging bank when alarmed (de Witte, 1941).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Advertisement Call

De Witte (1941) reported that the advertisement call is varied, at times sounding like a cat meowing, other times croaking like Rana esculenta, and sometimes illiciting a repeated “ri ki ki " cry.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Reproduction

It presumably breeds in forest streams where is has been collected (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Phylogenetics

Mitochodrial sequence data from 12S rRNA, valine-tRNA, and 16S rRNA fragment, as well as combined sequence data from mitochondrial and nuclear (RAG-1) genes indicate that P. acutirostris is the sister species to other large-bodies puddle frogs from the Albertine Rift, including P. dendrobates, P. petropedetoides, and P. versicolor (Zimkus, 2010). This group is also hypothesized to include P. dalcqui, P. irangi, and P. sulfureogularis.This group of puddle frogs in turn is sister to P. krefftii from East Africa.


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

IUCN Red List Category and Justification of Conservation Status

The IUCN Red List (2009) categorizes this species as Vulnerable because its Extent of Occurrence is less than 20,000 km2, its distribution is severely fragmented, and there is continuing decline in the extent and quality of its forest habitat in the Albertine Rift Mountains (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Trends

It is assumed that populations are decreasing (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Threats

It is probably affected by the increased collection of firewood and building materials if it is indeed a forest-dependent species (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/

Conservation Actions and Management

It has apparently been recorded from the Nyungwe National Park in Rwanda and the Virunga National Park in the Democratic Republic of Congo, and is known to occur in the Kahuzi-Biega National Park. However, the effectiveness of the conservation of these areas is probably compromised by the unstable political situation within its range. There is a need for further survey work in this region to better determine the distribution and current population status of this species (Pickersgill and Drewes, 2004).


Author: Zimkus, Breda
License: http://creativecommons.org/licenses/by-nc/3.0/