Description
Astylosternus perreti is a long-bodied West African frog in which male snout–vent length ranges from 40.5 - 48.0 mm with an average of 44.5 mm. The females range from 65 - 68 mm in snout–vent length with an average of 67.1 mm. This species has a long head with a pointed snout and an angular canthus rostralis. The tympanum to eye ratio is 38.25%. The dorsal integument is granulated and exhibits many flat, short ridges that converge at the center of the back. The tubercles on the forelimbs are long, skinny and unevenly distributed. The posterior limbs have small tubercles. The toe tips are spatulated and not dilated at the extremity. Webbing is moderately developed on the feet (Amiet 1977). The last phalanx of toes II - V is recurved and can protrude through the ventral skin of the toe, likely used to defend the frog by scratching potential predators (Blackburn et al. 2008). Males during breeding season have a double nuptial pad and no gular spines (Amiet 1977).

The tadpoles have a total length from 78.0 - 108.1 mm and a body length of 25.0 mm with a body length to total length ratio of 31.2 ± 2.2%. The ventral-fin-height to dorsal-fin-height ratio is 79.9 ± 6.8%. The keratodont formula is 1:2+2/2+2:1. The anterior lip has only a few lateral papillae. The posterior papillae are organized in two or three rows of 20 - 30 small, broadly triangular (shark tooth shaped) papillae; the medial papillae are larger than the lateral ones. The rostral gaps are large and the jaw sheaths are massive and serrated. The upper jaw is broadly arched with a small medial projection (fang), and the lower jaw narrowly U- to V-shaped (Griesbaum et al. 2019).

Dorsal coloration of adults is pale brown, yellow, or sometimes pale red with slightly visible spots or pale marbling. The canthus rostralis is black. The ventral coloration is pale yellow whereas the underside of the throat is pink with brown spots. Brown spots also mark the flanks, separating the dorsal and ventral coloration. The hind limbs have four to seven oblique transversal bars that are uninterrupted, unlike in other Astylosternus (Amiet 1977).

Tadpole dorsal coloration is dark brown while the tail is very pale brown to beige. The lateral sacs and ventrum are paler brown or dark gray. A broad, dark brown longitudinal band on the tail axis reaches to about the middle or two-thirds of the tail length, the proximate end of the tail has smaller dark speckles, and the fins are pale yellowish beige. The jaw sheaths are black (Griesbaum et al. 2019).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (28 records).

Astylosternus perreti is found in montane regions in the Cameroon Volcanic Line of southwestern Cameroon, where it is associated with fast flowing streams at elevations between 1200 and 1710 meters. It can be found in either dense or degraded forests, and is most often seen along steep, precipitous stream banks near torrents (Amiet 1977; Channing and Rödel 2019; IUCN 2021). Its presence has been confirmed through surveys in the following areas: Mt. Manengouba, Mt. Bana, Mt. Mbos (Amiet 1977), Mt. Nlonako (Herrmann et al. 2005), and Mt Kupe (Hofer 1999).

Life History, Abundance, Activity, and Special Behaviors
The adults are nocturnal (Channing and Rödel 2019 ) and active during the breeding season in November, December, or February. The male advertisement calls are described by Amiet as "Krak"or "Krik" high pitch for 0.1 second or "Kraa" for 0.3 second (Amiet 1977).

On Mt. Nlonako and Mt. Kupe A. perreti was found to occur at the same sites as A. diadematus and A. montanus (Hofer 1999; Plath et al. 2004).

Trends and Threats
Populations of this species are suspected to be decreasing because of severe habitat loss within its small range caused by clearance for agricultural land, human settlements, and logging (IUCN 2021).

Relation to Humans
This species is eaten in some villages within its range, although it is likely not consumed at levels that constitute a major threat to the species (IUCN 2021).

Comments
Preliminary genetic studies have found two clades in the genus Astylosternus, a West African Clade and a Central African clade (Portik et al. 2019). Astylosternus montanus is likely found in the Central African clade (Allen et al. unpubl. data).

References

Amiet, J.-L. (1977). ''Les Astylosternus du Cameroun (Amphibia Anura, Astylosterninae).'' Annales de la Faculté des Sciences de Yaoundé, 23/24, 99-227.

Blackburn, D. C., Hanken, J., Jenkins Jr, F. A. (2008). "Concealed weapons: erectile claws in African frogs." Biology Letters 4, 355–357. [link]

Griesbaum, F., Hirschfeld, M., Barej, M. F., Schmitz, A., Rohrmoser, M., Dahmen, M., Mühlberer, F., Liedtke, H.C. Gonwouo, N.L., Doumbia, J., Rödel, M. O. (2019). "Tadpoles of three western African frog genera: Astylosternus Werner, 1898, Nyctibates Boulenger, 1904, and Scotobleps Boulenger, 1900 (Amphibia, Anura, Arthroleptidae)." Zoosystematics and Evolution, 95, 133–160. [link]

Herrmann, H.-W., Böhme, W., Herrmann, P.A., Plath, M., Schmitz, A., Solbach, M. (2005). ''African biodiversity hotspots: the amphibians of Mt. Nlonako, Cameroon.'' Salamandra, 41(1/2), 61–81.

Hofer U, Bersier L-F, Borcard D (1999). ''Spatial organization of a herpetofauna on an elevational gradient revealed by null model tests.'' Ecology, 80(3), 976–988. [link]

IUCN SSC Amphibian Specialist Group. (2018). "Astylosternus perreti." The IUCN Red List of Threatened Species 2018: e.T54422A95847819. https://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T54422A95847819.en. Accessed on 19 January 2022.

Portik DM, Bell RC, Blackburn DC, Bauer AM, Barratt CD, Branch WR, Burger M, Channing A, Colston TJ, Conradie W, Dehlin JM, Drewes RC, Ernst R, Greenbaum E, Gvozdík V, Harvey J, Hillers A, Hirschfeld M, Jongsma GFM, Kielgast J, Kouete MT, Lawson LP, Leaché AD, Loader SP, Lötters S, van der Meijden A, Menegon M, Müller S, Nagy ZT, Ofori-Boateng C, Ohler A, Papenfuss TJ, Rößler D, SinschU, Rödel MO, Veith M, Vindum J, Zassi-Boulou AG, McGuire JA (2019). ''Sexual dichromatism drives diversification within a major radiation of African amphibians.'' Systematic Biology , 68(6), 859-875. [link]

Species Account Citation: AmphibiaWeb 2022 Astylosternus perreti <https://amphibiaweb.org/species/1487> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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