Description
Balebreviceps hillmani is a stout-bodied frog with females having a snout-vent length of 45 - 53 mm and males having a smaller length of 36 - 39 mm. In both males and females, the head and eyes are relatively small. The eyes are more horizontal in shape. The snout is rounded and truncated. Tympanums seem to be absent in this species. The skin texture on the dorsal side is glandular, thick, and deeply pitted. The ventral surface on the other hand, is smooth to weakly granular, except for the throat region, which is very wrinkled. Hind limbs are relatively short yet very muscular. Fingers are tapered and broad, with relative lengths of 1 < 2 < 4 < 3. The palms have tubercles that are well-developed. The feet, as well as toes, are both broad. The toes are tapered and lack webbing, with margins that are slightly compressed to form very faint, lateral flanges. The toes have relatives lengths of 1 < 2 < 5 < 3 < 4 (Largen and Drewes 1989).

Balebreviceps hillmani is differentiated from other Brevicipitidae by the presence of posteriorly curved clavicles and absence of middle ear elements. It also has a unique structured palate. The fifth metatarsal has a uniquely elongated proximate epiphysis. Both Balebreviceps and Probreviceps have noticeable longer hind limbs in comparison to Breviceps. Osteologically, the nasals of Balebreviceps are smaller and broadly separated, where as in Probreviceps, the nasals are larger and almost meet in the midline (Largen and Drewes 1989).

In life, expect to see a deep purple or brown color on the dorsal side, with a pair of pale yellow or golden stripes located dorsolaterally. The dorsal margins of the head are outlined by a similar pale-colored marking that extends all the way to the tip of the snout. The sides of the head are dark grey-brown with grayish-yellow spotting. The dorsolateral lines can often expand towards the midline and onto the head, so that the dark color in-between turns into a blob or completely disappears depending on the thickness of the lines. The hindlimbs are similar in color to the dorsolateral strips, and often even have a hint of orange. Sometimes they may also be a dark grey-brown color like the forelimbs. The forelimbs may also have dirty yellow blotches. The soles of the hands and feet are flesh colored and occasionally a pale grey. The ventral side is dirty yellow for the most part, although the belly is sometimes pale grey and the chest is often a pinkish color. In alcohol, expect to see the same dark purple brown color on the dorsum, and the dorsolateral stripes become a dirty cream color. The flank area is also a purplish-brown color with yellow or cream colored spotting. The venter is a cream color with markings that are a darker, purple or brown color (Largen and Drewes 1989).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Ethiopia

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (3 records).

All Balebreviceps hillmani have been found in the Bale Mountains of Ethiopia at an altitude of 3200 m under logs and boulders in woodland. There are many species of plants that create a closed canopy at a height of about 8-10m. The environment is very humid, and has a wet season lasting from March until October. Mosses and lichens are abundant (Largen and Drewes 1989).

Life History, Abundance, Activity, and Special Behaviors
When irritated, Balebreviceps hillmani responds defensively, by lowering the head and inflating the body with air. The body raises from the ground by stiffening and extending the limbs (Largen and Drewes 1989).

All Balebreviceps hillmani live an entirely terrestrial life cycle. Male Balebreviceps hillmani lack a vocal sac and both males and females lack an auditory apparatus, and thus this species is insensitive to airborne vibrations. Balebreviceps hillmani should be found above ground, as they do not seem to have a need to burrow. However, they do squeeze themselves into narrow crevices by using force exerted by the backward thrusts from the hindlimbs. At such a high elevation, there is minimal danger from predators, and the very moist environment removes the risk of desiccation (Largen and Drewes 1989).

Trends and Threats
When Balebreviceps hillmani was first discovered in 1986, the number of individuals was numerous. However, recent studies from 2006-2011 have found evidence of population decline, causing the species to be listed as Critically Endangered. All individuals of the species occupy a threat-defined location estimated to be about 5 km². The quality of this habitat in the Bale Mountains has also decreased, mostly due to human-induced habitat deterioration such as grazing, deforestation, fencing, and settlement development. A highway was built in 1983 to make the region more accessible, resulting in possible destruction of the forest and unregulated exploitation. Although it has not been confirmed, chytrid fungus could also impact population size, since it has been detected on this species as well as other amphibians in Ethiopia (IUCN 2013).

The Ethiopian Wildlife Conservation Organization is taking action by learning more about the forest in order to make educated recommendations for its protection (Largen and Drewes 1989).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments
Related genera include Breviceps and Probreviceps (Largen and Drewes 1989).

Balebreviceps gets its name after the Bale Mountains in southern Ethiopia (Largen and Drewes 1989).

References

IUCN SSC Amphibian Specialist Group. (2013). Balebreviceps hillmani. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org. Downloaded on 24 November 2014.

Largen, M. J. and Drewes, R. L. (1989). ''A new genus and species of brevicipitine frog (Amphibia, Anura, Microhylidae) from high altitude in the mountains of Ethiopia.'' Tropical Zoology, 2, 13-30.

Species Account Citation: AmphibiaWeb 2014 Balebreviceps hillmani <https://amphibiaweb.org/species/2369> University of California, Berkeley, CA, USA. Accessed Nov 25, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Nov 2024.

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