Description
Astylosternus nganhanus is an oval bodied West African frog with male snout–vent length averaging 45 mm. This species has a flattened head with a pointed snout and a small, rounded canthus rostralis. Astylosternus nganhanus has a tympanum to eye ratio of ~70%. The dorsal integument is mostly smooth with small wrinkles visible on the flanks. The supplementary tubercles of the hand are poorly developed; these are only visible on finger I and II of females and barely visible on males. The subarticular tubercle on finger I is very prominent. On the posterior limbs, the subarticular tubercles are small and round. The toe tips are not dilated. Webbing is extensive and extends from toe IV to the second tubercle of both toe III and V. Males, during breeding season, have a single, thick nuptial pad, and spines present around the mouth, on the lower jaw, and on the side of the head. Small spines are also found in the pectoral and gular regions (Amiet 1977).

The head coloration on adults exhibits a similar “tiara pattern similar to A. diadematus and A. montanus. The dorsum is covered with large semi-round markings bordered with black contours that become darker on the forearms. On the venter, males have dark pigmentation under the throat, abdomen, and legs, while the females only showed dark pigmentation under the throat. The hind limbs have a few poorly defined, irregular markings (Amiet 1977).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Cameroon

View distribution map in BerkeleyMapper.

Astylosternus nganhanus is found only on Mt. Nganha, Cameroon at elevations between 1400 - 1700 meters where it is associated with gallery forests and small streams in grasslands (Amiet 1977; Channing and Rödel 2019).

Life History, Abundance, Activity, and Special Behaviors
Very little is known about the life history of this species. Tadpoles that likely belong to this species have been found in rocky pools of streams (Channing and Rödel 2019).

Trends and Threats
The species is at risk due to habitat loss from small farms, subsistence wood extraction, and human settlements (IUCN 2021).

Comments
The phylogenetic affinity of Astylosternus nganhanus is unknown.

References

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

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.

IUCN SSC Amphibian Specialist Group. (2019). "Astylosternus nganhanus." The IUCN Red List of Threatened Species 2019: e.T54420A95847037. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T54420A95847037.en. Accessed on 18 January 2022.

Species Account Citation: AmphibiaWeb 2023 Astylosternus nganhanus: Nganha Night Frog <https://amphibiaweb.org/species/1485> University of California, Berkeley, CA, USA. Accessed Nov 13, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 13 Nov 2024.

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