Frogs and Toads from North America

What are Frogs and Toads? The frogs and toads form the group Anura, which means “no tail.” In addition to lacking a tail, the members of this group have other modifications for their jumping habit, including hind limbs longer than their forelimbs, a flexible pelvis, and posterior vertebrae fused into a urostyle. There is no scientific distinction between frogs and toads, but in general, frogs have smooth skin, live in the water and have longer hind limbs, whereas toads have dry, warty skin, live on land, and have shorter hind limbs. The fossil record of frogs and toads is patchy, in part because their delicate skeletons can break apart easily. One fossil from the Early Triassic of Madagascar has some characters of both salamanders and frogs, and has been called a “proto-frog,” but the earliest true frogs date back to the Early Jurassic.

First known fossil occurrence: Jurassic.

Last known fossil occurrence: Quaternary. This group has living relatives.