Microhylidae

Microhylidae is a geographically widespread family of frogs. There are 413 species in 69 genera and nine subfamilies, which is the largest number of genera of any frog family.

Description

As suggested by their name, Microhylids are mostly small frogs. Many species are below in length, although some species are as large as . They can be arboreal or terrestrial, and some will even habit close to water. The ground dwellers are often found under leaf litter within forests, occasionally venturing out at night to hunt. There are two main shapes for the Microhylids, one with wide bodies and narrow mouths, and the other with normal frog proportions. Those with narrow mouths generally eat termites and ants, and the others have diets typical of most frogs. The species of the genus Breviceps are burrowing frogs found in the arid regions of Africa. Some of their species will even lay their eggs under ground.

Reproduction

The Microhylids of New Guinea and Australia completely bypass the tadpole stage, with direct development from egg to frog. The arboreal species can therefore lay the eggs within the trees, and never need venture to the ground. Where species do have tadpoles, these almost always lack the teeth or horny beak typical of the tadpoles of other families.

Anatomy

The skull has paired palatines and frontoparietals. Facial nerve passes through anterior acoustic foramen in auditory capsule; trigeminal and facial nerve ganglia are fused to form a prootic ganglion. There are eight (or seven) presacral holochordal vertebrae and they are all precoelous except for a biconcave surface on last presacral. Pectoral girdle is firmisternal and some show reduced clavicle and procoracoids Terminal phalanges blunt, pointed or t-shaped. Tadpoles lack keratinized mouth parts and have a large spiracular chamber emptied by a caudomedial spiracle.

Range

Frogs from Microhylidae occur throughout the tropical and warm temperate regions of North America, South America, Africa, eastern India, Sri Lanka, south-east Asia, through New Guinea and Australia. Although most are found in tropical or sub-tropical regions, a few species can be found in arid or non-tropical areas. They are the majority frog species in New Guinea and Madagascar.

References

Cogger, H.G.; R.G. Zweifel, and D. Kirschner (2004). Encyclopedia of Reptiles & Amphibians Second Edition. Fog City Press. ISBN 1-877019-69-0.
Zug, George R.; Laurie J. Vitt and J.P. Caldwell (2001). Herpetology:An Introductory Biology of Amphibians and Reptiles 2nd Edition. Academic Press. ISBN 0-12-782622-X.