RhinophrynidaeBurrowing Toads
This family contains a single species (Rhinophrynus dorsalis). Rhinophrynus is a highly fossorial toad-like species found from extreme southern Texas to Costa Rica.
Rhinophyrnus has numerous primitive characteristics, such as an arciferal pectoral girdle, opisthocoelous vertebrae and inguinal amplexus. However, it is also highly modified for a fossorial lifestyle and many of its characteristics reflect this specialization. For example, a cornified spade is present on the heel of each foot. This spade combined with the short, powerful limbs make Rhinophrynus an accomplished burrower. In addition, the head is sharply pointed with small eyes and no tympana. Many of the structures associated with feeding are modified for feeding on ants and termites underground. Tongue morphology in Rhinophrynus is unique among frogs in that the tongue is projected straight out of a groove at the anterior end of the mouth rather than being flipped out as in other frogs.
These frogs are only active on the surface for a relatively brief time during breeding activities after heavy rains. Eggs are laid in temporary ponds, where Type 1 larvae develop. These larvae are filter feeders and lack the characteristic jaw sheaths and denticles of many other frog larvae, but have characteristic barbels.
Rhinophrynid fossils attributed to Rhinophrynus and one extinct genus are known from the Paleocene and Eocene of Wyoming, USA and the Oligocene of Saskatchewan, Canada.
Rhinophrynids are thought to be the sister group to the pipid frogs, mainly on the basis of similarities in their larvae.
Little is known about the conservation status of rhinophrynids, but amphibians in general are thought to be sensitive to changes in their environment (see AmphibiaWeb's declining amphibians page).
Duellman, W.M. and L. Trueb. 1984. Biology of the Amphibians.
Pough, F.H., R.M Andrews, J.E. Cadle, M.L. Crump, A.H. Savitzsky, K.D. Wells. 1998. Herpetology. Prentice-Hall, Upper Saddle River, NJ.
Frost, Darrel R. 2002. Amphibian Species of the World: an online reference. V2.21 (15 July 2002). Electronic database available at http://research.amnh.org/herpetology/amphibia/index.html.
Contributors
Richard M. Lehtenin (author).
Glossary
- bilateral symmetry
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having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- ectothermic
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animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- metamorphosis
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A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
- motile
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having the capacity to move from one place to another.