The Arthroleptidae (pron.: /ˌɑrθrɵˈlɛptɨdiː/) are a family of frogs found in sub-Saharan Africa. They are also known as squeakers because of their high-pitched calls. They are small, less than 4 cm (1.6 in) in length, terrestrial frogs found mostly in leaf litter on the forest floor. They completely bypass any aquatic stage, so do not have tadpoles. They lay their eggs on the ground, in crevices or in leaf litter, and the offspring undergo direct development. Some species hatch already completely metamorphosed into the adult form, while others still have tails when they hatch.^[1]

Overview

This family contains a unique frog, the hairy frog (Trichobatrachus robustus). 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 the hairs are thought to 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 it may project through the skin, apparently by intentionally breaking the bones of the toe ^[1]. 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 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 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.^[2]

Taxonomy

The Arthroleptidae ares separated into two subfamilies: Arthroleptinae and Leptopelinae. Some consider these to be separate families.

The two subfamilies consist of these genera:

References

^ *" 'Horror frog' breaks own bones to produce claws." NewScientist.com, 2008

^ *Amphibian Species of the World - Arthroleptidae Mivart, 1869

Further information

• ADW: Arthroleptidae: Information
• Cogger, H.G.; R.G. Zweifel, and D. Kirschner (2004). Encyclopedia of Reptiles & Amphibians Second Edition. Fog City Press. ISBN 1-877019-69-0.

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