This species name is in honor of Louis Fraser, the researcher who collected the first specimens of in 1852 (Boulenger 1905, Evans et al. 2019).

Description
Xenopus fraseri is a small, aquatic frog native to sub-saharan Africa. Male members of the species tend to be smaller than the females; X. fraseri males average 38.5 mm while X. fraseri females average 46.5 mm (Evans et al. 2019). The body is flattened and streamlined for its aquatic lifestyle, this includes the presence of a specialized organ for the production of sound underwater. The skin is smooth. The tip of the rostrum is rounded. Relative finger lengths are 3 > 4 ≈ 2 > 1. The thigh is slightly shorter than the shin. The toes are fully webbed and relative toe lengths are 3 > 4 > 5 > 2 > 1 (Evans et al. 2015).

DIAGNOSIS:

Xenopus fraseri is often confused with other members of the Xenopus genus, as all species within are morphologically similar (Ernst et al. 2015). Morphological features that may be used to identify X. fraseri are the presence of vomerine teeth and prehallux claws. The only members of the genus that have vomerine teeth are X. muelleri and X. fischbergi. However, these two species lack prehallux claws. Xenopus fraseri may also be easily misidenitfied as its sister species, X. fischbergi, one possible way of telling these two species apart is X. fraseri tends to be much smaller than X. fischbergi (Evans et al 2019). Ernst et al. (2015) claim X. fraseri is easy to mistake as X. andrei. Morphological features that can be used to differentiate these two are the number of epidermal mechanoreceptors, or “stitches”, in the lateral line system. This method may be unreliable though, as the average number of stitches on X. andrei is 16 and the average amount of stitches on X. fraseri is 16 - 19. A more reliable morphological feature would be the number of periocular stitches, which is higher (9 - 12 periocular stitches) in X. andrei (Ernst et al. 2015).

COLORATION::

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon, Ghana, Uganda

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (36 records).

Distribution of the Xenopus genus as a whole is not clearly understood and the distributions of different species that are published in the literature may be incorrect due to under sampling in sub-saharan Africa and misidentifying members of the genus. Specifically regarding Xenopus fraseri, its distribution is often confused with X. andrei because of their similar morphology (Ernst et al 2015). Evans et al. (2019) places X. fraseri distribution in northern Ghana and northern Cameroon, and claims this species is primarily distributed in relatively hot, arid savanna. However, there is some variation in literature of the distribution of X. fraseri. Ernst et al. (2015) claims that X. fraseri is found in low-land forests of the Congo Basin and is a forest-bound species. The IUCN places X. fraseri throughout Ghana, Togo, and Benin, and claims that it is possibly distributed throughout Angola, Central African Republic, and the Democratic Republic of the Congo (IUCN 2017). If Ernest et al. (2015)'s assessment is accurate, X. fraseri is one of few members of its genus to be found south of the Congo Basin. The upper and lower limits of X. fraseri distribution range is unclear (IUCN 2017).

Life History, Abundance, Activity, and Special Behaviors
Xenopus fraseri spends most of its life in slow moving water or stagnant pools, and occasionally migrates between bodies of water (Evans et al. 2015). A diet study on X. fraseri found they will eat a wide variety of organisms. The diet of the study group consisted of only invertebrates. The absence of vertebrate prey in the diet may be due to no vertebrate prey being available at the time, however, it was noted that X. fraseri are “clumsy predators” possibly making it difficult for X. fraseri to catch vertebrate prey in the first place. Juveniles were found to consume more aquatic prey while adults had an even split of aquatic and terrestrial prey. The higher number of terrestrial prey consumed by adults may be explained by conspecific competition, or competition with other aquatic animals such as other amphibians and fish (de Bruyn et al. 1996).

Trends and Threats
Although X. fraseri is listed as data deficient by the IUCN, their population size is still noted as decreasing. A possible reason for the decline is collection of the frog for both food and the pet trade. Another factor may be the general decline in habitat quality. This species occurs throughout several protected areas (IUCN 2017).

Relation to Humans
This species has been harvested for human consumption and for the pet trade (IUCN 2017).

Comments

PHYLOGENETIC RELATIONSHIPS:

Whole genome mitochondrial sequences were analyzed from the X. fraseri type specimen and several other Xenopus specimens using Maximum Likelihood and Bayesian methods. The study found that this species is the sister taxa to X. fischbergi and is firmly within the X. muelleri species complex, which also includes X. borealis. Xenopus fraseri appears to be more recently diverged and may have resulted from an allotetraploid event. This relationship is supported by morphological comparisons (Evans et al. 2019).

OTHER INTERESTING INFORMATION

The Xenopus genus is unique in the fact that nearly all of its members are allopolyploid (Evans et al. 2019).

References

Boulenger, G.A. (1905). "On a Collection of Batrachians and Reptiles made in South Africa by Mr. C. H. B. Grant, and Presented to the British Museum by Mr. C. D. Rudd." The Zoological Society of London, 75(3), 248-255.

De Bruyn, L., Kazadi, M., Hulselman, J. (1996). "Diet of Xenopus fraseri (Anura, Pipidae) ." Journal of Herpetology , 30(1), 82-85. [link]

Ernst, R., Schmitz, A., Wagner, P., Futuro Branquima, M., Hölting, M. (2015). "A window to Central African forest history: distribution of the Xenopus fraseri subgroup south of the Congo Basin, including a first country record of Xenopus andrei from Angola." Salamandra, 52(1), 147-155. [link]

Evans, B.J., Carter, T.F., Greenbaum, E., Václav Gvoždík, V., Kelley, D.B., McLaughlin, P.J., Pauwels, O.S.G., Portik D.M., Stanley E.L., Tinsley E.C., Tobias, M.L., Blackburn, D.C. (2015). "Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa." PLOS ONE, 10(12). [link]

Evans, B.J., Gansauge, M.-T., Stanley, E.L., Furman, B.L.S., Cauret, C.M.S., Ofori-Boateng, C., Gvoždik, V., Streicher, J.W., Greenbaum, E., Tinsley, R.C., Meyer, M., Blackburn, D.C. (2019). "Xenopus fraseri: Mr. Fraser, where did your frog come from?" PLoS One, 14(9), e0220892. [link]

IUCN SSC Amphibian Specialist Group. 2017. Xenopus fraseri. The IUCN Red List of Threatened Species 2017: e.T89257302A18397804. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T89257302A18397804.en. Downloaded on 13 December 2020.

Species Account Citation: AmphibiaWeb 2024 Xenopus fraseri: Fraser’s Clawed Frog <https://amphibiaweb.org/species/5253> University of California, Berkeley, CA, USA. Accessed Mar 28, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 28 Mar 2025.

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