hear Fonozoo call (#1)
	hear Fonozoo call (#2)

Description
Nyctibates corrugatus is a Central African frog with a maximum snout-vent length of 55 mm in males and 66 mm in females (Channing and Rödel, 2019). The species has a large head (approximately as long as it is broad), large eyes, and a prominent canthus rostralis. The snout slants from the nostrils to the mouth with a white-edged upper lip. Its loreal region is concave and the nostrils are equidistant from the eye to the end of the snout. The tympanum is roughly three-fifths of the diameter of the eye. Vomerine teeth are present in two small groups between the large choanae. Its limbs are slender, toe tips are rounded, and the first finger is longer than the second. There is moderate webbing in the toes with strong subarticular tubercles and a small, oval, inner metatarsal tubercle (Boulenger 1904).

The call of N. corrugatus differs from that of Scotobleps and Astylosternus by its brevity (Amiet and Schiotz 1973).

In life, the species consists of two different chromatic types, independent of sex and found in equal proportion (Amiet, 1973). Half of the population is typically a light purple or slate gray, whereas the other half is caramel red or ocher. The species is marked by an occipital triangle (which may not always be visible) with a yellow bar between the eyes, highlighted posteriorly with a thin dark line. A characteristic of this species that is rare in other species of the Arthroleptidae is a series of five to seven pairs of yellowish subrounded spots that straddle the midline and begin just behind the cephalic triangle and ending behind the sacrum. The dorsal hind limbs are the same color as the body with fine irregular transversal black bands. The transverse bands correspond to thin integumentary folds in the skin that can give the frog a finely wrinkled appearance. The anterior and posterior sides of the thigh and underside of the leg are bright blue dotted with black. The tops of the forelimbs have dark transverse folds while the outer edge of the forelimbs, knees, and upper mandible are densely speckled with white. The ventral side of the frog is a slightly translucent white or pink (Amiet 1973).

There is weak sexual dimorphism and males and females are generally similar in size. There is no hypertrophy of the front limbs in males. The only notable dimorphism is that males have a black throat, which is white in females (Amiet 1973), and that the linea alba is often visible through the transparent ventral skin of males (Amiet 1973).

Distribution and Habitat

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

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (5 records).

Nyctibates corrugatus is found throughout southeastern Nigeria (Frétey and Blanc 2000, Channing and Rödel 2019), beginning around the Oban Hills, southern Cameroon (Amiet 1973, 1975, 1978, Lawson 1993, Herrmann et al. 2005) Equatorial Guinea (Lasso et al. 2002), and northwestern Gabon (Frétey and Blanc 2000, Channing and Rödel 2019). Its presence has been confirmed through surveys in the following areas: in Cameroon, Mt Kupe (Portik et al. 2016), Mt Nlonako (Herrmann et al. 2005), and Korup National Park (Lawson 1992); in Equatorial Guinea, Monte Alén National Park (De la Riva 1994, Hurley 2023); and in Gabon, Mibounzi Cave in the Ogooué-Lolo Province (Pauwels et al. 2019), and the Estuaire Province (Neil and Jongsma 2016)

The species primarily lives in habitats ranging from sea level to about 800 – 900 meters in elevation, these frogs are exclusively found in low plains and forests that are humid but not marsh-like, preferring regions of forest that are hilly and well-drained (Amiet 1973). During the reproductive season, the species can be found on the edges of small, rocky, rivers where the tadpoles live hidden under the stones. The species calls far from the water, typically within leaf litter (Amiet 1975). During the day the species resides within leaf litter (Amiet 1973).

Life History, Abundance, Activity, and Special Behaviors
During the daytime, the species rests in a crouched position. Movements are slow and typically either walking or small hops (Amiet 1973).

Breeding populations are dispersed, the males call far from near the water, sometimes up to 10–20 meters away. The breeding period in Central Cameroon is short, spanning from September to the end of November. In southern Cameroon, the breeding season extends until April or May (Amiet and Schiotz, 1973). The breeding season typically ends abruptly, with all frogs ceasing to call within a week (Amiet 1973).

Calls consist of a short, high-pitched “roua” of a fairly pure tone emitted regularly at intervals of 5 – 10 seconds. The call is produced following rapid swelling of the vocal sac before it empties. During the reproductive period, calls are emitted at dusk beginning around 6:00 PM, lasting typically for 10 – 18 hrs (Amiet and Schiotz, 1973).

The clutch size of eggs is approximately 75, with eggs connected by a flexible cord (Amiet 1973).

The species may play dead when captured, straightening the arms and curving the spine backward (Amiet 1973).

Larva
Tadpoles are very long and robust with a strong, muscular tail (Amiet 1971, Channing et al. 2012). The body shape ranges from oblong and oval (in a dorsal view) to flat and elongated with an abdomen larger than the head. The body contains lateral sacs spanning from the short spiracle on the left side to the end of the body, with the vent tube located on the right side. Body length ranges from 37 – 39% of total length, body height ranges from 25 – 33% of body length, and body width ranges from 39 – 40% of body length. The eyes and nostrils are located dorsolaterally. The eye diameter ranges from 5 – 7% of body length. The nostrils are located closer to the tip of the snout than to the eyes. The snout is rounded. The inter-nostril distance ranges from 78 – 88% of the interorbital distance. The mouth is ventral, located close to the snout, and is smaller than the interorbital distance. The labial tooth formula is 1/1. The anterior labium is composed of two semicircular lobes whose edges bear a line of small papillae, with a minimal gap between the lobes. The posterior labium is a broad, flat lobe containing approximately 20 – 30 uniform, small, circular, papillae with a few additional widely spaced small papillae arranged in a single transverse row across the labium. The jaws are dark in color and are deeply ridged. The upper jaw curves with a medial fang while the lower jaw is V-shaped without indentation. The tail tapers to a pointed tip with narrow tail fins. The ventral fin extends from the base of the tail and the dorsal fin extends from the first third of the tail. The height of the ventral fin ranges from 73 – 80% of the dorsal fin height with the last third of the tail being the tallest. Body height is 73 – 90% of maximum tail height. Tail axis width ranges from 50 – 56% of body width. Tail axis height ranges from 55 – 69% of maximum tail height (Greisbaum et al. 2019).

The ventral side of the tadpole is grayish (Amiet 1971). When preserved, the body, tail, and fins are uniformly brown, whereas the underside is brighter with a grayish hue. The ventral fin appears more translucent and brighter compared to the dorsal fin. In their natural state, tadpoles are dark brown to nearly black, with a hint of blue along the lower portions of their sides, belly, and tail (Greisbaum et al. 2019).

Tadpoles are only found in rivers with clear water and a rocky stream bed. Tadpoles occasionally live in crevices within accumulations of rocks or boulders (Amiet 1971). Tadpoles of N. corrugatus have been found in caves in Gabon but it is not known whether the eggs were laid within the caves (Pauwels et al. 2019).

The obtuse and flattened muzzle of the tadpole is likely used to push stones and leaves while foraging. The diet of the tadpole is exclusively vegetarian, consisting of dead leaves softened by long immersion in water (Amiet 1971).

Trends and Threats
This species is listed as "Least Concern" by the IUCN, and is known to be locally common, although declines in some areas due to habitat loss are expected (IUCN 2013).

Relation to Humans
No known relations to humans (IUCN 2013)

Comments
Nyctibates is a monotypic genus in the family Arthroleptidae. It is sister to a clade containing the genera Scotobleps, Astylosternus, and Trichobatrachus (Feng et al. 2017, Portik et al. 2023).

References
Amiet, J. L. (1971). Le têtard d’Astylosternus corrugatus Boulenger (Amphibien Anoure). Annales de la Faculté des Sciences du Cameroun, 6, 85–98.

Amiet, J. L. (1973). Notes faunistiques, éthologiques et écologiques sur quelques Amphibiens Anoures du Cameroun (2e série). Annales de la Faculté des Sciences de Yaoundé, 13, 135–161.

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

Amiet, J. L. and Schiotz, A. (1973). Voix d’Amphibiens camerounnais. I. Astylosterninae: genres Leptodaciylodon, Seotobleps et Nyctibates. Annales de la Faculté des Sciences du Cameroun, 12, 79–100.

Boulenger, G. A. (1904). Descriptions of two new genera of frogs in the family Ranidae from Cameroon. Annals and Magazine of Natural History, Series 7, 13, 261–262. [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.

De la Riva, I. (1994). Anfibios anuros del Parque Nacional de Monte Alén, Río Muni, Guinea Ecuatorial. Revista Española de Herpetología, 8, 123–139.

Feng, Y.-J., Blackburn, D.C., Liang, D., Hillis, D.M., Wake, D.B., Cannatella, D.C., and Zhang, P. (2017). Phylogenomics reveals rapid, simultaneous diversification of three major clades of Gondwanan frogs at the Cretaceous–Paleogene boundary. PNAS 114(29), E5864–E5870. [link]

Frétey, T., and Blanc, C. P. (2000). Les amphibiens d’Afrique centrale. ADIE, Libreville, Gabon.

Griesbaum, F., Hirschfeld, M., Barej, M., Schmitz, A., Rohrmoser, M., Dahmen, M., Mühlberger, F., Liedtke, H. C., Gonwouo, N. L., Doumbia, J., and 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(1), 133–160. [link]

Herrmann, H.-W., Bohme, W., Herrmann, P. A., Plath, M., Schmitz, A., and Solbach, M. (2005). African biodiversity hotspots: the amphibians of Mt. Nlonako, Cameroon. Salamandra, 41(1/2), 6–81. [link]

Hurley, S. L. (2023). The amphibians of Monte Alén National Park: bioacoustics, ecology and conservation. [Masters Thesis, University of Bristol] Bristol University Archive. [link]

IUCN SSC Amphibian Specialist Group. (2013). Nyctibates corrugatus. The IUCN Red List of Threatened Species: e.T54441A18360769. https://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T54441A18360769.en. Accessed on 29 February 2024.

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].

Neil, E. J., and Jongsma, G. F. M. (2016). Geographic distribution. Nyctibates corrugatus. Herpetological Review, 47(4), 623–624. [download]

Pauwels, O. S., Carlino, P., Chirio, L., Daversa, D. R., Lips, J., Oslisly, R., and Testa, O. (2019). Amphibians and reptiles found in caves in Gabon, western Equatorial Africa. Cave and Karst Science, 46(1), 3–12. [link]

Portik, D. M., Jongsma, G. F. M., Kouete, M. T., Scheinberg, L. A., Freiermuth, B., Tapondjou, W. P., and Blackburn, D. C. (2016). A survey of amphibians and reptiles in the foothills of Mount Kupe, Cameroon. Amphibian and Reptile Conservation, 10(2), 37–67. [link]

Portik, D.M., Streicher, J. W., Blackburn, D. C., Moen, D. S., Hutter, C. R., and Wiens, J. J. (2023). Redefining possible: combining phylogenomic and supersparse data in frogs. Molecular Biology and Evolution 40(5), msad109. [link]

Species Account Citation: AmphibiaWeb 2024 Nyctibates corrugatus <https://amphibiaweb.org/species/1480> University of California, Berkeley, CA, USA. Accessed Jan 26, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Jan 2025.

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