83.
Mazumbai Warty Frog
(Callulina kisiwamsitu)
EN
Overview
This is an intensely warty species that is both ground-dwelling and tree climbing. The Mazumbai warty frog is one of only two species in its genus, and is fairly small (measuring 30-40 mm in length), with males being markedly smaller than females. Eggs are laid in dark, damp locations and undergo direct development, hatching as froglets. It is found in damp mountain forests with dense undergrowth, and is presumed to be intolerant to habitat degradation. Although it is found in three forest reserves, none of these protected areas provide a completely safe refuge and all are threatened by some degree of habitat destruction, through factors such as logging and agriculture.
Urgent Conservation Actions
Improved the management of forest reserves where this species is found, working with local communities to develop sustainable farming and firewood harvesting in the area.
Distribution
West Usambara Mountains of Tanzania.
Fact
The specific name for the Mazumbai warty frog, Callulina kisiwamsitu, derives from the Swahili “kisiwa”, meaning island and “msitu”, meaning forest. This refers to the fragmented habitat of this species that is now just a remnant, patchy forest that once covered the West Usambara Mountains.
Associated Blog Posts
6th Aug 12
The Mazumbai warty frog (Callulina kisiwamsitu) has a very interesting lineage. Its family (Brevicipitidae) is a group of 26 unique frogs from Africa that us...  Read

Media from ARKive
ARKive image - Mazumbai warty frog
ARKive image - Mazumbai warty frog on stem
ARKive image - Mazumbai warty frog, lateral view
ARKive image - Mazumbai warty frog showing skin detail
ARKive image - Mazumbai warty frog on leaf
Evolutionary Distinctiveness
Order: Anura
Family: Brevicipitidae
The Brevicipitidae family is a group of highly rotund frogs from Africa that usually have burrowing lifestyles and a highly characteristic appearance, with a bulbous body and tiny head. Previously a subfamily of the Microhylidae (the “narrow-mouthed frogs”) and called the Brevicipitinae, the Brevicipitidae family actually started to diverge from the narrow-mouthed frogs about 130 million years ago in the Early Cretaceous. There are 26 species currently assigned to newly recognised Brevicipitidae family. They started to evolve separately from all other modern amphibians about 65 million years ago, at a time when the dinosaur abruptly became extinct. This makes them as different from all other amphibians as whales are to giraffes! The genus Callulina (commonly known as the “warty frogs” diverged 40 million years ago within the Brevicipitids – this intra-family split therefore occurred about 5 million years before the origin of monkeys.

For nearly 100 years since the discovery of the first warty frog (Callulina kreffti), this genus was presumed to be monotypic (i.e. containing only a single species). However, in 2004 scientists realised that Callulina kreffti actually comprised two species – the original Callulina kreffti was confined to the in the East Usambara Mountains and a new species, the Mazumbai warty frog (Callulina kisiwamsitu) was present in the West Usambara Mountains. Although these two species look rather similar, an amphibian survey in Tanzania in 1999–2000 discovered that the warty frog from the West Usambara could be distinguished from the warty frog in the East Usambara (where Callulina kreffti was first officially discovered) by their advertisement call. The peak dominant frequency of the advertisement call of the Mazumbai warty frog is always below 2 Khz, whereas the peak dominant frequency in Callulina kreffti is always above 2 Khz (usually around 2.5–2.6 KHz). Subsequent analyses of the external morphology (of physical make-up) and DNA sequence data of warty frogs from West and East Usambara supported the recognition of these two disjunct populations as distinct species. The population from the West Usambara Mountains was described as a new species, bringing the grand total of warty frogs to just two species. Confined to Tanzania, they are highly distinct and unusual members of the Brevicipitidae family.
Description
The Mazumbai warty frog, as its common names would suggest, is absolutely covered in a uniform layer of small, prominent warts, giving its skin an extremely bumpy appearance. It grows to lengths of 30-40 mm and has a stout, rounded body with short, slender limbs and moderately long hands and feet. The tips of the relatively long digits have adhesive discs, and the first and second toes are opposable, aiding grip whilst climbing. The head is small and has a distinctly rounded, foreshortened snout. This species has rounded nostrils, large brown eyes, and visible ovoid eardrums. The colouration of this species is brown with irregular dark brown marbling and a thin cream line running down the centre of the back. The warts on the sides of the body are white. The ventral (or lower) surface, including the stomach, chest and throat, is cream with brown marbling on the edges. Females are larger than males.
Ecology
The Mazumbai warty frog is a ground dwelling as well as climbing species. There is no aquatic tadpole stage, and instead the embryonic and larval development up to metamorphosis takes place within the eggs. This species therefore breeds by “direct development”. The eggs are deposited in dark, damp locations, as is the case with their close relatives, the globular African rain frogs (of the genus Breviceps), which lay their eggs in underground chambers, where they develop into froglets. The short arms and rotund body of the Mazumbai warty frog is likely to render amplexus (the mating embrace) rather difficult. Added to these unfavourable body dimensions is the fact that the males, who must grasp the female from behind, are by far the smaller sex. Although little is known of the breeding habits of the warty frogs, it is possible they are similar to that of the African rain frogs. The highly bulbous, short-limbed African rain frogs manage their amplexus (mating embrace) by being very sticky – the male literally sticks himself to the female so that he can remain in an appropriate position to fertilise her eggs as they are released. The Mazumbai warty frog is also known to be very sticky.

Mazumbai warty frogs commence their mating calls when the rainy season starts, generally at night between the hours of 20:00 and 23:00. The males climb into low bushes and other vegetation where they start to call. It has often been observed that calling males position themselves vertically on small trunks, from 0.5–2 m off the ground. Their warty, camouflaged appearance meant that they were initially mistaken for notches in the trunks. They have also been found calling at the junction of branches. The call is a long trill composed of 8–18 notes, at an average call duration of 126 milliseconds. There is an average of 5.44 pulses per note and the intensity of the dominant frequency is around 1.84 KHz, which is significantly lower than that of its sister species Callulina kreffti in the East Usambara Mountains.

Through the examination of the stomach contents of one specimen of this species, the Mazumbai warty frog is known to feed on relatively large arthropods (Hemiptera or bugs, Orthoptera or crickets, and Diplopoda), and nematode worms.
Habitat
The Mazumbai warty frog is found in damp mountain forests with dense undergrowth, and is presumed to be intolerant to habitat degradation. It is both terrestrial and partially arboreal.
Distribution
This species is known from remnant forest patches in the West Usambara Mountains of Tanzania, namely: Mazumbai Forest Reserve; Ambangula Forest Reserve; Shume-Mugambo Forest Reserve; and Lushoto. The Mazumbai warty frog is likely to occur widely in the West Usambaras, wherever forest remains.
Population Estimate
There is no information on the abundance of this species.
Population Trend
This species is thought to be in decline by the IUCN Red List of Threatened Species.
Status
The Mazumbai warty frog is listed as Endangered in the IUCN Red List of Threatened Species because it has an area of occupancy and extent of occurrence of less than 500 km sq., within which remaining habitat is severely fragmented and declining in both quality and overall area.
Threats
Habitat loss due to smallholder agriculture is likely to be a threat to unprotected forests within the range of the Mazumbai warty frog. Habitat degradation may also be a threat through both logging activities and extraction of firewood, including within protected areas.
Conservation Underway
Three of four known sites for this species are within Forest Reserves: Mazumbai Forest Reserve; Ambangula Forest Reserve; and Shume-Mugambo Forest Reserve. However, all of these protected areas are subject to threats, such as smallholder agriculture and, logging, and firewood extraction.
Conservation Proposed
It is important that habitat is conserved effectively for this highly unusual species. Despite occurring in three protected areas, it seem this species is not receiving sufficient protection against habitat destruction and fragmentation. Improved management of these Forest Reserves is a vital first step in the conservation of the Mazumbai warty frog. This should include working with local communities to find more sustainable and ecologically sensitive ways of harvesting wood and farming in the area. It would probably be beneficial to the Mazumbai warty frog to increase habitat continuity within its range by connecting some of the forest fragments where it is found. This would increase the ability of remaining individuals to disperse and move their genes between potentially isolated populations.
Links
References
AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: amphibiaweb. Accessed: 08 December 2006.

Evans, S.E., Milner, A.R. and Werner, C. 1996. Sirenid salamanders and gymnophionan amphibian from the Cretaceous of the Sudan. ***

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

Frost, D. R., Grant, T., Faivovich, J., Bain, R.H., Haas, A., Haddad, C. F. B., De Sá, R.O., Channing, A., Wilkinson, M., Donnellan, S.C., Raxworthy, C.J., Campbell, J.A., Blotto, B.L., Moler, P., Drewes, R.C., Nussbaum, R.A., Lynch, J.D., Green, D.M., and Wheeler, W.C. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370.

Gower D. J., & Wilkinson, M. 2005. The conservation biology of caecilians. Conservation Biology 19: 45-55.

Gower, D. J., Loader, S. P., Moncrieff, C. B. and Wilkinson, M. 2004. Niche separation and comparative abundance of Boulengerula boulengeri and Scolecomorphus vittatus (Amphibia: Gymnophiona) in an East Usambara forest, Tanzania. African Journal of Herpetology 53: 183-190.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. . Accessed on 08 December 2006.

Jones, D. T., Loader, S. P. and Gower, D. J. 2006. Trophic ecology of East African caecilians (Amphibia: Gymnophiona), and their impact on forest soil invertebrates. Journal of Zoology, London 269: 117-126.

Kupfer, A., Muller, H., Jared, C., Antoniazzi, M. M., Nussbaum, R. A., Greven, H. & Wilkinson, M. 2006. Parental investment by skin feeding in a caecilian amphibian. Nature 440: 926-929.

Malonza, P.K. & Measey, G.J. 2005. Life history of an African caecilian: Boulengerula taitanus (Caeciilidae: Amphibia: Gymnophiona). Tropical Zoology 18: 49-66.

Measey, G. J. 2004. Are caecilians rare? An East African perspective. Journal of East African Natural History 93: 97-117.

Measey, G. J. 2007. When is an earthworm not an earthworm? When it’s a Critically Endangered amphibian. The Story of the Kilima-mrota. Personal communication.

Measey, G. J. and Barot, S. 2006. Evidence of seasonal migration in a tropical subterranean vertebrate. Journal of Zoology 269(1) : 29-37.

Measey, G. J. and Herrel, A. 2006. Rotational feeding in caecilians: putting a spin on the evolution of cranial design. Biology Letters 2: 485-487.

Müller, H., Measey, G.J., Loader, S.P. and Malonza, P.K. 2005. A new species of Boulengerula Tornier (Amphibia: Gymnophiona: Caeciliidae) from an isolated mountain block of the Taita Hills, Kenya. Zootaxa 1004: 37-50.

Measey, J., Malonza, P. & Mueller, H. 2006. Boulengerula niedeni. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. . Downloaded on 17 September 2007. Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.

Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.

. Accessed: 08 December 2006.

Channing, A., Howell, K. & Loader, S. 2006. Callulina kisiwamsitu. In: IUCN 2006. 2006 IUCN Red List of Threatened Species.
IUCN Red List of Threatened Species. Downloaded on 31 July 2007.

De Sá, R.O., Loader, S.P. and Channing, A. 2004. A new species of Callulina (Anura: Microhylidae) from the West Usambara Mountains, Tanzania. Journal of Herpetology 38: 219–224.

Duellman, W. E. and Trueb, L. 1986. Biology of Amphibians. McGraw-Hill, New York.

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

Frost, D. R., Grant, T., Faivovich, J., Bain, R.H., Haas, A., Haddad, C. F. B., De Sá, R.O., Channing, A., Wilkinson, M., Donnellan, S.C., Raxworthy, C.J., Campbell, J.A., Blotto, B.L., Moler, P., Drewes, R.C., Nussbaum, R.A., Lynch, J.D., Green, D.M., and Wheeler, W.C. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. Global Amphibian Assessment. Accessed on 08 December 2006.

Mattison, C. 1987. Frogs and toads of the world. Blandford Press, U.K.

Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.

Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.

if you can provide new information to update this species account or to correct any errors, please email us at info@edgeofexistence.org


Forum comments

There are as yet no comments for this species.

Add a comment

You must log in to post. If you don't have a login, it's easy to register.