A medium-sized (both sexes up to 36 mm) arboreal treefrog from the central forest. Dorsum warty, black or brownish to olive with an hourglass pattern consisting of very irregular transverse bands on dorsum and limbs. The male has no vocal sac or vocal sac openings, but has a pair of sub-mandibular glands, 4 x 2,5 mm. They are apparently mute. The male also has strong spines on tarsus. The digital discs of males are larger than those of the females.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Cameroon, Congo, the Democratic Republic of the, Gabon, Nigeria
Rainforest from south-eastern Nigeria to Mayombe, R.D.Congo and to north-eastern R.D.Congo (Kivu).
Life History, Abundance, Activity, and Special Behaviors
Based on observations in captivity, Perret (1961) suggests that the sexes may be attracted to each other by smell.
Acanthixalus spinosus is arboreal and apparently mainly aquatic. It spends its days and breeds in the small bodies of water which accumulate in cavities in living and dead trees. The frogs sit submerged with only the tip of the snout above water. Presumably they leave their refuge at night to hunt. A strange defence mechanism is described by Perret: the frog half-closes its eyes, keeps its limbs immovable close to the body and extends its orange tongue.
Development: The eggs are laid in a small hemispherical mass of jelly, 3–4 cm in diameter. The egg mass contains only 8–10 yellow eggs with a diameter of 2 mm, deposited a few centimetres above the water surface in the water-bodies in trees. The hatching larvae fall into the water where they spend approximately three months, feeding on the debris and algae in their little basin. Newly metamorphosed juveniles are orange above with the top of the head, a broad bar across the middle of the back and another in the lumbar region deep maroon.The tadpole attains a maximum length of 60 mm and has a tooth formula of 1,3+3/3.
This account was taken from "Treefrogs of Africa" by Arne Schiøtz with kind permission from Edition Chimaira publishers, Frankfurt am Main.
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.
Schiøtz, A. (1999). Treefrogs of Africa. Edition Chimaira, Frankfurt am Main.
Written by Arne Schiøtz (arne AT schiotz.dk), *
First submitted 2000-12-25
Edited by Arie van der Meijden (2001-01-08)
Species Account Citation: AmphibiaWeb 2001 Acanthixalus spinosus <http://amphibiaweb.org/species/441> University of California, Berkeley, CA, USA. Accessed Jul 6, 2020.
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Citation: AmphibiaWeb. 2020. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 6 Jul 2020.
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