Description
Astylosternus laurenti is a long-bodied West African frog in which males range from 42.5–48 mm in snout-vent length with an average of 44.6 mm and females range from 55.5 - 62.5 mm. This species has a broad head with a short snout, rounded canthus rostralis, and broken tympanic ridge. The tympanum to eye ratio is 43.8%. Small tubercles are present on the eyelids and on the top of the head. The dorsal integument is highly wrinkled, and the forearms are granulated and irregular. The anterior limb tubercles are prominent but not conical with small supplementary tubercles at the base of finger I, II, and sometimes IV. On the first finger I, the tubercles are longer (Amiet 1977). The toe tips are slightly dilated and there is a moderate amount of webbing and a visible tarsal fold. 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).

Tadpoles have a total length of 51.7 mm. The body length to total length ratio is 34.2%. The ventral-fin-height to dorsal-fin-height ratio is 72.2%. The keratodont formula is 1:2+2/2+2:1. Anterior lip papillae are positioned laterally and posterior lip papillae are organized in two or three rows of 20 triangular papillae. Papillae of the inner row are shorter than the marginal row. The rostral gaps are large and the jaw sheaths are massive and serrated. The upper jaw has a small medial fang, and the lower jaw is U-shaped with a broad medial notch (Griesbaum et al. 2019).

The thigh of A. laurenti is relatively shorter and wider than in A. fallax, and this is a useful character for distinguishing these two species (Amiet 1977).

Adult dorsal coloration varies from brown to beige or olive with irregular, round black spots. Ventral coloration is bright yellow, becoming pink under the throat, with scattered light brown spots under the limbs. The hind limbs have 4 to 8 small interrupted, transverse bars(Amiet 1977).

Tadpole coloration is pale brown, and the dorsal surface is darker with irregular, dark brown spotting; the ventral surface is pale with little or no dark speckling. The tail fin is beige and semi-transparent with tiny dark brown spots. 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 (1 records).

Astylosternus laurenti is found in the Cameroon Volcanic Line of Southwestern Cameroon in densely forested lowland and hilly regions from 400 - 850 meters in elevation (Amiet 1977; Channing and Rödel 2019). Its presence has been confirmed through surveys in the vicinity of Rumpi hills, Mt Kupe, Mt. Manengouba, Mt. Nlonako, the Bamileke plateau (Amiet 1975, 1977), and Korup National Park (Lawson 1992).

While this species was noted to occur in Maholé, in the foothills of Mt. Kupe by Amiet (1977), it was not detected in that area in later studies (Hofer et al. 1999; Schmitz et al. 1999; Euskirchen et al. 1999; Portik et al. 2016). Similarly at Ekomtolo on Mt. Nlonako this species was identified by Amiet (1975) who designated the site as the type locality, but it has not been recovered in more recent surveys (Herrmann et al. 2005; Plath et al. 2004).

Life History, Abundance, Activity, and Special Behaviors
The adults are nocturnal and active during the breeding season from April to mid-November (Amiet 1977).

Males are found calling under rocks on steeply sloping faces above slow moving rivers or rocky streams (Amiet 1977; Channing and Rödel, 2019). Amiet (1977) described the call as two- or three-second "hoiin" and a ½ -second "rroooa".

If it still occurs at all its historical sites, it should co-occur with A. diadematus, A. perreti, and A. fallax (Herrmann et al. 2005; Plath et al. 2004).

Trends and Threats
The population size of A. laurenti is decreasing due to habitat loss and degradation, primarily resulting from human settlement, agricultural encroachment, and logging (IUCN 2021).

Relation to Humans
It has not been confirmed but it may be consumed by people (IUCN 2021)

Comments
Preliminary genetic studies have found two clades in the genus, a West African clade and a Central African clade (Rödel et al. 2012; Portik et al. 2019). Astylosternus laurenti likely falls into 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.

Amiet, J.L. (1975). ''Ecologie et distribution des amphibiens anoures de la région de Nkongsamba (Cameroun).'' Annales de la Faculté des Sciences de Yaoundé, 20, 33-107.

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

Channing, A., Rödel, M.-O. (2019). Field Guide to the Frogs and Other Amphibians of Africa. Penguin Random House South Africa, Cape Town, South Africa.

Euskirchen, O., A. Schmitz & W. Böhme (1999). ''Zur Herpetofauna einer montanen Regenwaldregion in SW-Kamerun (Mt. Kupe und Bakossi-Bergland) II. Arthroleptidae, Ranidae und Phrynobatrachidae.'' Herpetofauna, 21(122), 25-34.

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]

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. (2017). "Astylosternus laurenti." The IUCN Red List of Threatened Species 2017: e.T54418A95843221. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T54418A95843221.en. Accessed on 12 January 2022.

Lawson, D. P. (1992). "The herpetofauna of Korup National Park, Cameroon: biogeography and comparative biodiversity of a tropical African rainforest." Doctoral dissertation, The University of Texas at Arlington

Plath M, Solbach M, Herrmann H-W (2004). ''Anuran habitat selection and temporal partitioning in a montane and submontane rainforest in southwestern Cameroon – first results.'' Salamandra (Frankf), 40, 239-260. [link]

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]

Portik, D. M., Jongsma, G. F. M., Kouete, M. T., Scheinberg, L. A., Freiermuth, B., Tapondjou, W. P., Blackburn, D. C. (2016). "A survey of amphibians and reptiles in the foothills of Mount Kupe, Cameroon." Amphibian & Reptile Conservation, 10, 37–67. [link]

Rödel, M.-O., Barej, M. F., Hillers, A., Leaché, A. D., Kouamé, N.G., Ofori-Boateng, C., Assemian, N. E., Tohé, B., Penner, J., Hirschfeld, M., Doumbia, J., Gonwouo L.N., Nopper, J., Brede, C., Diaz, R., Fujita, M.K., Gil, M., Segniagbeto, G.H., Ernest, R., Sandberger, L. (2012). "The genus Astylosternus in the Upper Guinea rainforests, West Africa, with the description of a new species (Amphibia: Anura: Arthroleptidae)." Zootaxa, 3245, 1–29. [link]

Schmitz, A., Euskirchen, O. and Böhme, W. (1999). ''Zur Herpetofauna einer montanen Bergwaldregion in SW-Kamerun (Mt. Kupe und Bakossi-Bergland) 1. Einleitung, Bufonidae und Hyperoliidae.'' Herpetofauna, 21(121), 5-17.

Species Account Citation: AmphibiaWeb 2022 Astylosternus laurenti <https://amphibiaweb.org/species/1483> University of California, Berkeley, CA, USA. Accessed Dec 27, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 27 Dec 2024.

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