Hairy Frog

Taxobox
name = Hairy Frog


image_caption = male, showing hair-like papillae
image_width = 240px
status = LC | status_system = IUCN3.1
regnum = Animalia
phylum = Chordata
classis = Amphibia
ordo = Anura
familia = Astylosternidae
genus = "Trichobatrachus"
species = "T. robustus"
binomial = "Trichobatrachus robustus"
binomial_authority = Boulenger, 1900
synonyms =

The Hairy Frog ("Trichobatrachus robustus") is a species of frog in the Astylosternidae family. It is monotypic within the genus "Trichobatrachus".

Description

The species is about 11 cm long from snout to length. The large head is broader than long, with a short rounded snout.Males are much larger than females. The former have a paired internal vocal sac and three short ridges of small black spines along the inner surface of the first manual digit. They also have dermal papillae that extend along the lateral surfaces of the body and the proximal hindlimbs. These contain arteries and are thought to increase the surface for the purpose of respiration, due to the small lungs and robust body of the species. These papillae look somewhat like hairs, leading to the common name of the species.

Biology

The species is terrestrial, but returns to the water for breeding, where egg masses are laid onto rocks in streams. The quite muscular tadpoles are carnivorous and feature several rows of horned teeth. Adults feed on slugs, myriapods, spiders, beetles and grasshoppers.

Breeding male Hairy Frogs develop highly vascularised, hair-like projections on their thighs and flanks. They will sit on their eggs for long periods of time, and it is thought that the hairs assist in respiration through the skin, while they cannot use their lungs in the water.

The hairy frog is also notable in possessing retractable "claws" (though unlike true claws, they are made of bone, not keratin), which is may project through the skin, apparently by intentionally breaking the bones of the toe ref|claw. In addition, the researchers found a small bony nodule nestled in the tissue just beyond the frog's fingertip. When sheathed, each claw is anchored to the nodule with tough strands of collagen, but, as Blackburn had discovered firsthand, when the frog is grabbed or attacked, the frog breaks the nodule connection and forces its sharpened bones through the skin.

Amphibian researcher and biologist David Wake of the University of California, Berkeley, says that this type of weaponry appears to be unique in the animal kingdom. But David Cannatella, a herpetologist at the University of Texas, Austin, questions whether the bony protrusions are meant for fighting. They could allow a frog's feet "to get a better grip on whatever rocky habitat they might be in," he says. [http://sciencenow.sciencemag.org/cgi/content/full/2008/528/2]

This is probably a defense behavior. Although a retraction mechanism is not known, it has been hypothesized that the claws later retract passively, while the damaged tissue is regenerated.

Distribution

It is found in Cameroon, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Nigeria, possibly Angola, and possibly Republic of the Congo.Its natural habitats are subtropical or tropical moist lowland forests, rivers, arable land, plantations , and heavily degraded former forest.

Endangered status

"T. robustus" is threatened by habitat loss, but is not considered endangered.

Human use

This species is roasted and eaten in Cameroon. They are hunted with long spears or machetes, apparently to avoid being hurt by their claws.

References

[http://www.newscientist.com/article/dn13991-horror-frog-breaks-own-bones-to-produce-claws.html?DCMP=ILC-hmts&nsref=news2_head_dn13991 " 'Horror frog' breaks own bones to produce claws." NewScientist.com, 2008]
* [http://research.amnh.org/herpetology/amphibia/references.php?id=189 Amphibian Species of the World - Arthroleptidae Mivart, 1869]
* AmphibiaWeb: [http://amphibiaweb.org/cgi/amphib_query?query_src=aw_lists_genera_&where-genus=Trichobatrachus&where-species=robustus "Trichobatrachus robustus"]
* (2004): [http://www.iucnredlist.org/search/details.php/54443/all Trichobatrachus robustus] . [http://www.iucnredlist.org 2006 IUCN Red List of Threatened Species. ] Retrieved on July 21, 2007.
* NewScientist news service: [http://www.newscientist.com/channel/life/dn13991-horror-frog-breaks-own-bones-to-produce-claws.html?feedId=online-news_rss20 'Horror frog' breaks own bones to produce claws] Retrieved on June 9, 2008.
* (2008): Concealed weapons: erectile claws in African frogs. "biology letters" (published online). doi|10.1098/rsbl.2008.0219 — [http://publishing.royalsociety.org/media/biology_letters/rsbl20080219.pdf PDF]

External links

*eol|16141937