Description
Astylosternus batesi is a West African frog with males that range from 45.0 - 53 mm in snout–vent length with an average of 50 mm. The females are generally larger with a maximum of 73.5 mm and an average of 66 mm in snout–vent length. This species has a compact, rounded body, a broad, flat head and a short, pointed snout with a small, distinct canthus rostralis. The tympanum to eye ratio is between 86% and 96% (Amiet 1977). The dorsal integument is smooth with only a few very small folds or granules on eyelids, arms, and legs. The hind feet exhibit a small extent of webbing, and toe tips are slightly dilated. 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 (Parker 1931, Blackburn et al. 2008). Males, during breeding season, have a single nuptial pad and no gular spines (Amiet 1977).

Tadpoles have a total length ranging from 20.7 - 25.2 mm, with a body length of 7.6 - 7.9 mm, and a tail length of 13.1 - 17.3 mm. The body length to total length ratio is 31.3 - 36.7%. The ventral fin height is between 1 mm to 3 mm and the dorsal fin height is between 1.4 mm and 4 mm. The keratodont formula is 1:2/2+2:1. The anterior lip papillae are positioned laterally, the posterior lip papillae are in 2 or 3 rows of 20 uniform papillae. Papillae are triangular and approximately as long as broad. The rostral gap is large and the jaw sheath is massive and serrated. The upper jaw has a large medial projection and the lower jaw is U-shaped with a medial notch (Griesbaum et al. 2019).

The dorsal coloration of adults ranges from dark brown to black with small, scattered spots on the back and much larger spots, outlined in black, on the flanks. The hind limbs have a general brownish coloration with four to seven darker transverse bars (Amiet 1977). The ventral coloration is yellow under the abdominal area, going to pink under the throat, and darker under the lower legs (Parker 1931, Blackburn et al. 2008).

Tadpoles are brown, with irregular dark speckles on the dorsal surface. The ventral surface is plain with few to no dark spots. The tail fins are sometimes covered with dark blotches. The jaw sheath is black (Griesbaum et al. 2019).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon, Central African Republic, Congo, Congo, the Democratic Republic of the, Equatorial Guinea, Gabon

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (17 records).

Astylosternus batesi is found throughout southern Cameroon, Equatorial Guinea, and Gabon. Its range extends from the Sanaga River in Cameroon to southern Central African Republic (CAR) and the western half of Republic of Congo (Amiet 1977, 1986, De La Riva 1994, Channing and Rödel 2019, IUCN 2021, Larson and Zimkus 2018). It inhabits streams and small rivers in lowland and submontane primary, secondary and gallery rainforest at elevations between 0 to 1000 m (Amiet 1977, Channing and Rödel 2019). The most extensive surveys of this species have been conducted in Gabon where it has been recorded from three national parks: Crystal Mountains (Lötters et al. 2001), Ivindo (Frétey and Blanc 2000), and Moukalaba-Doudou (Burger et al. 2004), as well as the mouth of at least one cave system (Lipopa Cave, Ogooué- Lolo Province, Gabon; Pauwels et al. 2019).

Life History, Abundance, Activity, and Special Behaviors
The adults are nocturnal (Amiet 1977).

The reproductive season occurs from March to June and from September to December, corresponding with the end of the two rainy seasons and beginning of the dry seasons (Amiet 1977). During the breeding season males call near small streams. Amiet describes the males’ call as "glouk-hou," "rrrroua," and “crroa,” typically at a rate of ~1 note/second. The eggs are laid in pools of still water as large clusters connected to submerged roots or branches (Amiet 1977, Channing and Rödel 2019).

Trends and Threats
This species has a decreasing population trend due primarily to farming and logging. Chytrid is present in the area, but it is unknown if it affects the population size (IUCN 2021).

Comments

Phylogenetic relationships

Preliminary genetic studies have found two clades in the genus, a West African clade and a Central African clade (Portik et al. 2019). The phylogenetic placement of A. batesi likely falls into the Central African clade (Allen et al. unpublished data). Several phylogenies place A. batesi as closely related to (Portik and Blackburn 2016, Portik et al. 2019), and sometimes polyphyletic with A. schioetzi (Deichmann et al. 2017).

Comments

Astylosternus batesi was removed from synonymy with A. diadematus by Amiet (1978).

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. (1986). ''La batrachofaune sylvicole d’un secteur forestier du Cameroun: la région de Yaoundé.'' Mémoires du Muséum national d’histoire naturelle, Sér. A., Zoologie, 132, 29–42.

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

Burger, M., Branch, W.R., Channing, A. (2004). "Amphibians and reptiles of Monts Doudou, Gabon: Species turnover along an elevational gradient." Monts Doudou, Gabon: A Floral and Faunal Inventory with Reference to Elevational Variation. Fisher, B.L., eds., California Academy of Sciences, San Francisco, California, USA, 145–186.

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.

Deichmann JL, Mulcahy DG, Vanthomme H, Tobi E, Wynn AH, Zimkus BM, McDiarmid RW (12). ''How many species and under what names? Using DNA barcoding and GenBank data for west Central African amphibian conservation.'' PLoS One, 2017(11), e0187283. [link]

Frétey, T., Blanc, C.P. (2000). "Liste des amphibiens d’Afrique centrale: Cameroun, Congo, Gabon, Guinée-Equatoriale, République Centrafricaine, République Démocratique du Congo, São Tomé et Príncipe." Les dossiers de l’ADIE, Série Biodiversité 2, 1–39.

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]

IUCN SSC Amphibian Specialist Group. (2019). "Astylosternus batesi." The IUCN Red List of Threatened Species 2019: e.T54415A18390475. Downloaded on 27 October 2021

Largen, M. J. and Dowsett-Lemaire, F. (1991). ''Amphibians (Anura) from the Kouilou River Basin, République du Congo.'' Tauraco Research Report, 4, 145-168.

Larson, J. G., Zimkus, B. M. (2018). "Preliminary assessment of the frog assemblages from sites adjacent to three national Parks in Gabon." Herpetological Conservation and Biology, 13, 240–256. [link]

Lötters, S., Gossmann, V., Obame, F., Böhme, W. (2001). "Zur Herpetofauna Gabuns Teil I: Einleitung, Untersuchungsgebiet und Methodik, kommentierte Artenliste der gefundenen Froschlurche." Herpetofauna, 23, 19–34.

Parker, H.W. (1931). "XLV.—Some new and rare frogs from West Africa." Annals and Magazine of Natural History, series 10, 7, 492-498.

Pauwels, O. S., Carlino, P., Chirio, L., Daversa, D. R., Lips, J., Oslisly, R., Testa, O. (2019). "Amphibians and reptiles found in caves in Gabon, western Equatorial Africa." Cave and Karst Science, 46, 3–12. [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., Blackburn, D. C. (2016). "The evolution of reproductive diversity in Afrobatrachia: A phylogenetic comparative analysis of an extensive radiation of African frogs." Evolution, 70, 2017–2032. [link]

de la Riva, I (1994). ''Anfibios anuroś del Parque Nacional de Monte Alén, Rió Muni, Guinea Equatorial.'' Revista Española de Herpetologia , 8, 123–139.

Species Account Citation: AmphibiaWeb 2022 Astylosternus batesi: Bates' Night Frog <https://amphibiaweb.org/species/1479> University of California, Berkeley, CA, USA. Accessed Sep 20, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 20 Sep 2024.

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