Hair frog
| Hair frog | ||||||||||||
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Hair frog ( Trichobatrachus robustus ); dried museum specimen |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Trichobatrachus | ||||||||||||
| Boulenger , 1900 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Trichobatrachus robustus | ||||||||||||
| Boulenger , 1900 |
The hair frog ( Trichobatrachus robustus , Syn .: Astylosternus robustus ) is a species of the frog auger (Anura), which is currently counted to the family of long finger frogs (Arthroleptidae) after it was temporarily placed in a family Astylosternidae. It is named after the closely spaced, filamentous skin flaps ("hair") that the males develop during the mating season.
features
The hair frog reaches an average length of eleven centimeters, with the males being significantly larger than the females. The body color is olive green to brown, there are black bands between the eyes and on the back. The frog has a broad head with a short, rounded snout. The nostrils are closer to the eyes than to the tip of the snout, the eyes have perpendicular pupils . The eye-catching eardrum is about half the diameter of the eye.
A peculiarity that the hair frog shares with some related species is the formation of claws. However, unlike the clawed frog ( Xenopus laevis ), these do not consist of horny nails. Instead, they are actively formed by the frogs by breaking the bones of the toes from a specially created sheath and then penetrating the skin of the toes. The resulting very sharp claws are probably used primarily to defend against potential attackers.
The animals show a pronounced sexual dimorphism . The males have paired internal vocal sacs and three rows of black teeth on the forefeet, which are probably used to hold on to the female during mating. Particularly noticeable are the eponymous thready skin flaps that the males develop on the flanks and hind legs during mating season. They are close together and are ten to fifteen millimeters long. The purpose of these glandular protuberances with strong blood supply has not yet been clarified - various functions such as tactile or respiratory organs ( skin breathing ) would be conceivable, but do not appear to be absolutely necessary. There was also speculation about an auxiliary function in attaching the eggs to stones in fast-flowing waters (“spawning brush”), a camouflage function (imitation of algae) or a courtship function of this secondary gender characteristic. A background as a sex signal is probably the most likely - but it is also possible that other males should be prevented from attempting mismatches by touch stimuli.
distribution and habitat
The range of the hair frog stretches from the Osomba Hills in southwestern Nigeria across parts of western and southwestern Cameroon and Equatorial Guinea to the Mayombe Hills in the Democratic Republic of the Congo and Gabon . Deposits are assumed for the Republic of the Congo and the Cabinda enclave ( Angola ).
The frog lives terrestrially in the lowland rainforest in the area of fast-flowing rivers as well as in former rainforest areas in secondary forests and agricultural areas, especially in tea plantations . The tadpoles live in deep water areas and in potholes under waterfalls.
Way of life
Little data is available on the way of life of the hair frog. It is believed that it lives terrestrially on the forest floor and only visits the water to reproduce and lay eggs. By examining the stomach contents, it could be determined that it feeds on snails , millipedes , spiders , beetles and grasshoppers .
The female lays her spawning packages on stones in rivers. Muscular tadpoles hatch out of these and have several rows of horn teeth on their mouth and feed on predatory food.
threat
The hair frog is classified in the IUCN Red List as Least Concern. There is no detailed information about the frequency, only the species seems to be comparatively rare in the vicinity of Yaoundé . However, due to its large distribution area, the hair frog is considered a common species.
Individual evidence
- ↑ David C. Blackburn, James Hanken, Farish A. Jenkins Jr: Concealed weapons: erectile claws in African frogs Biological Letters 4, 2008; Pp. 355-357; ( PDF )
- ↑ Trichobatrachus robustus in the endangered Red List species the IUCN 2008 Posted by: Jean-Louis Amiet, Marius Burger, 2004. Accessed on March 28 of 2009.
