Description
Sclerophrys superciliaris is a large sized African giant toad. Adults were described as having robust bodies with a male snout-urostyle length range of 116.0 - 128.4 mm while females had a larger snout-urostyle length range of 108.1 - 153.4 mm. The mean width of the head is similar for both males and females, with the width being 38% of the snout-urostyle-length in males and 39% in females. The head is bony and does not have any ridges. The snout is slightly rounded and short when viewed from a lateral perspective, and the nostrils are closer to the snout tip than to the eyes. The canthus rostralis is distinct and angular. The loreal region is straight yet slightly concave. The eye-snout distance is similar to the eye diameter. The eyelids are triangular in shape from dorsal and lateral views and have a distinct prolongation in the middle. The tympanum is positioned at a concave part of the cheeks and is vertically prolonged while the horizontal diameter is smaller than the eye diameter. The parotid glands are prominent and are shaped like a slender drop converging backwards with a pointed tip. The gland openings are only on the dorsal part of the parotids. The ratio of parotid length over parotid width is 3.17 in males while in females it is 3.23. In some specimens, a glandular bulge extends from the area posterior to the parotids to the groin and forms a dorsolateral fold. In adults, the dorsal skin is smooth. The fingers and toes are simple and are not enlarged at the end. The unwebbed fingers have a relative length of III > I > II ≥ IV. Nuptial pads are present on fingers I and II in male specimens. The thigh is short and slender. The mean tibia length is 38% of the snout-urostyle-length in both males and females. While tarsal folds are absent in most specimens, an indistinct bulging of the skin has been observed in some of the examined specimens. The inner and outer metatarsal tubercles are present. The subarticular tubercles are simple. The toes have a relative length of IV > III > V > II > I and rudimentary webbing with a formula of 1 (0.5), 2 (1 - 0.5), 3 (2 - 1) or 3 (2 - 1.25), 4 (2.75 - 2.75), 5 (1) or 5 (1.25) (Barej et al. 2011).

Juveniles have granular skin with warts on the dorsum until they reach about 40 mm in size. Additionally, in small juvenile specimens, the eyelid process is less distinct and is hardly visible. Single tiny bulges are also observed on the eyelids (Barej et al. 2011).

DIAGNOSIS:

African frogs from the Bufo genus, which S. superciliaris was formerly assigned to, are generally poorly distinguished due to their conservative morphology and conserved karyotypes (Cunningham and Cherry 2004). Sclerophrys superciliaris was previously assigned to both the Bufo and Amietophrynus genera and can be differentiated from species in those genera based on several characteristics. Specificially, adult S. supercilaris have smooth dorsal skin, a straight loreal region, and are larger in size compared to Amietophrynus members (Barej et al. 2011).

Compared to other closely related Sclerophrys, in the lateral view, the eyelid process of S. superciliaris is triangular similar to S. channingi but different from the rounded eyelid process of S. chevalieri. Additionally, compared to the broad and rounded tipped parotid glands of S. chevalieri and S. channingi, the parotid glands in S. superciliaris appear slender and have a pointed tip. Furthermore, S. superciliaris can be distinguished by its reddish to reddish-purple flank coloration contrasting it from the brownish flanks of S. channingi and the red to dark purple or purple-brownish flank coloration in S. chevalieri. On the dorsum, S. superciliaris has a pair of spots on a pale background located at the posterior third of the body, differing from S. channingi that displays paired dark spots on a darker posterior dorsal coloration, and S. chevalieri that only has a darker posterior dorsal coloration. Lastly, S. superciliaris differs geographically from the other species. Specifically, S. superciliaris is found in western Lower Guinea whereas S. chevalieri is found in Upper Guinea and S. channingi is found in eastern Lower Guinea (Barej et al. 2011).

COLORATION:

In life, the dorsal surface coloration varies from a pale yellowish to a marbled orange yellow extending from the tip of the snout to the upper portion of the parotids then posteriorly. The parotids are distinctly bi-colored, with the dorsal surface colored as stated in the previous sentence and the lateral, lower part resembling coloration of the flanks. Starting at the tip of the snout, there is an intense red coloration that may fade in intensity as it continues beneath the canthus rostralis and onto the flanks. A pair of dark spots are present on the posterior third of the dorsum. In a few adult specimens, smaller dark spots may be present on the anterior part of the dorsum or between the eyes. The inguinal region may also have small spots. The limbs are dark purple and the hind limbs and feet have white transverse bars. The gular region and venter are purple and the belly is pale. The anterior extremities are ventrally dark purple (Barej et al. 2011).

In life, the juveniles have a similar coloration to the adults, but have additional transversal bars on the tibiofibula. Additionally, more spots are present on the dorsum and in the interorbital region. In the interorbital region, a pair of small blotches converge posteriorly with each other, barely reaching the eyelids. Some juveniles have lighter vertebral lines. Juveniles also have a brown-black coloration in the gular and chest region, in contrast to adults with pale bellies (Barej et al. 2011).

In preservative, specimens lose their reddish coloration and fade to brownish. The reddish coloration is only retained where it is covered between skin folds. While older specimens are usually bleached out, resulting in the lack of color pattern, there are still many specimens where the lateral and dorsal coloration is distinguishable (Barej et al. 2011).

VARIATION:

A female observed in 1898 was described to have a pale red-brown upper surface and chocolate-brown flanks, however, it is unclear if this specimen was of S. superciliaris (Barej et al. 2011).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon, Central African Republic, Equatorial Guinea, Gabon, Nigeria

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (11 records).

This species inhabits rainforest and primary forest or swampy localities in the western Lower Guinean region, which includes Nigeria, Cameroon, Gabon, and Equatorial Guinea (Barej et al. 2011).

Life History, Abundance, Activity, and Special Behaviors
Sclerophyrs superciliaris reside on the forest floor in primary forest habitats near small rivers. During rainy seasons, the species can be found in swamp sites. Additionally, they have been observed in areas with dense vegetation and plantation sites. However, the species has also been observed foraging in more open spaces. They are relatively inactive during the rain season. During one observation in the rainy season, a male specimen was observed remaining idle for long periods of time, moving only about 25 meters over a four-day period (Barej et al. 2011).

Breeding males were observed to have hypertrophied anterior limbs and black callosities on fingers I and II (Barej et al. 2011).

Sclerophyrs superciliaris males do not have a vocal sac and have not been observed to have an advertisement call. However, a dull, buzzing vocalization consisting of a long series of pulses that lasted for 1.0 to 1.5 seconds has been recorded. Only the flanks were observed to be moving during this vocalization, which could only be heard from short distances. As a result, the researchers concluded the vocalization is only useful for short distance recognition rather than as an advertisement call (Barej et al. 2011).

Clutches of S. superciliaris eggs are deposited in slowly running streams. The egg sizes range from 1.40 mm to 1.95 mm. Reproduction is believed to occur during the dry season, from January to March, as most specimens are observed during this period, and with males displaying their nuptial morphology. In January, juveniles of the species were observed in both Nigeria and Cameroon (Barej et al. 2011).

In captivity, the species feeds on insects, snails, beef meat, and on other frogs and tadpoles (Barej et al. 2011).

Trends and Threats
Since 2016, S. superciliaris has been listed as “Least Concern” by the IUCN, however, this assessment still includes S. chevalieri as a subspecies. The habitat of S. superciliaris has been threatened by both logging and mining. While the use of S. supercilaris in international trade has been significantly reduced, it is still used in traditional medicine. Sclerophrys superciliaris can be found in several protected areas, which play a crucial role in its conservation. These include the Oban Hills National Park in Nigeria, the Korup National Park in Cameroon, and the Monte Alen National Park in Equatorial Guinea (IUCN 2019).

Relation to Humans
While S. superciliaris is used by the indigenous people in traditional medicine, they are also believed to cause harm. Specifically, the species has an important role in traditional medicine for the people of Mt. Nlonako, who also believe the toad transmits leprosy, and villagers near the Ebo Forest in Cameroon fear that the toad’s saliva can damage human skin. In western Cameroon, the toad's bones are used to treat poisoning and mental disorders. Bakossi healers also use the frogs in traditional medicine, and the Bakola-Pygmies of southern Cameroon utilize the parotid secretion of the species to envenom arrowheads for hunting. In southwestern Cameroon, it is believed that these toads can signal the change of seasons by altering their position (Barej et al. 2011).

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Urbanization
Mining
Intentional mortality (over-harvesting, pet trade or collecting)

Comments
As of 2025, there is no a comprehensive tree for this genus. However, Barej et al. (2011) found that S. superciliaris is most closely related to S. chevalleri and then S. channingi based on genetic distances. Specifically, S. superciliaris and S. chevalieri have a genetic distance of 0.0093 ± 0.0008 while S. superciliaris and S. channingi have a genetic distance of 0.0280 ± 0.0007 (Barej et al. 2011). Additionally, an earlier study of genetic divergence found that the tropical forest species, such as Sclerophrys brauni and S. superciliaris, were separated from temperate and highland occurring species, such as Sclerophrys capensis and Sclerophrys kisolensis, and dry savannah species, which include Sclerophrys garmani and Sclerophrys xeros (Cunningham and Cherry 2004).

Barej et al. (2011) re-categorized the focal taxon to the genus Amietophrynus and differentiated it through various characteristics. However, based on morphology, Ohler and Dubois (2016) re-assigned it again to Sclerophyrs.

OTHER INTERESTING INFORMATION:

Between 2011 and 2019, Sclerophrys chevalieri was treated as a subspecies of S. superciliaris, however, Barej et al. (2011) also noted that while the two species are similar genetically, they are morphologically and geographically distinct. In 2019, Rödel and Glos treated Sclerophrys chevalieri and S. superciliaris as two different species.

References
Barej, M. F., Schmitz, A., Menegon, M., Hillers, A., Hinkel, H., Böhme, W., and Rödel, M.-O. (2011). Dusted off—the African Amietophrynus superciliaris-species complex of giant toads. Zootaxa, 2772(1), 1–32. [link]

Cunningham, M., and Cherry, M. I. (2004). Molecular systematics of African 20-chromosome toads (Anura: Bufonidae). Molecular Phylogenetics and Evolution, 32(3), 671–685. [link]

IUCN SSC Amphibian Specialist Group. (2019). Sclerophrys superciliaris. The IUCN Red List of Threatened Species 2019: e.T46203837A16215747. https://dx.doi.org/10.2305/IUCN.UK.2019-1.RLTS.T46203837A16215747.en. Accessed in April 2025.

Ohler, A., and A. Dubois. 2016. The identity of the South African toad Sclerophrys capensis Tschudi, 1838 (Amphibia, Anura). PeerJ 4(e1553): 1–13. [link]

Rödel, M.-O., and J. Glos. 2019. Herpetological surveys in two proposed protected areas in Liberia, West Africa. Zoosystematics and Evolution 95, 15–35. [link]

Species Account Citation: AmphibiaWeb 2025 Sclerophrys superciliaris: Cameroon Toad <https://amphibiaweb.org/species/287> University of California, Berkeley, CA, USA. Accessed Jun 9, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 9 Jun 2025.

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