Frogs and toads are amphibians that do not typically have a tail as adults. The hind legs are longer than the front legs and are modified for jumping. The body is relatively short and the head is not separated from the body by a discernable neck. The larval or tadpole stage of most frogs and toads is entirely aquatic. Tadpoles possess a tail and do not have legs until late in development, just prior to metamorphosis to the adult form. Frog and toad tadpoles with legs can be distinguished from aquatic salamander larvae by the lack of a discernable neck, the presence of distinctly longer back limbs compared to the front limbs, and the absence of external gills, as are seen in salamander larvae.
True toads have thick, dry, warty skin and have enlarged, warty glands in the shoulder region called parotoid glands. Unlike most frogs, true toads tend to produce short hops to escape danger rather than long leaps (Conant and Collins 1998).
There are only two species of true toads found in Maryland. They include the eastern American toad (Anaxyrus americanus americanus) and the Fowler’s toad (Anaxyrus fowleri).The two species can be distinguished from each other based on the number of warts in each pigmented spot on the dorsum, the presence or absence of conspicuously enlarged warts on the tibia, spotting on the chest, and the amount of separation between the cranial crest and the parotoid glands (Conant and Collins 1998).
True frogs have long powerful hind legs with webbed feet. They have relatively stout waists and large broad mouths. The toes do not have discs or pads at the tips as in the treefrogs (Hylidae). All of the true frogs found in Maryland have smooth skin with no bumps or tubercles, and most have ridges that run along the sides of the back (dorsolateral ridges). All Maryland frogs in Family Ranidae are in the genus Lithobates.
Many true frog tadpoles grow relatively large and may have an extended larval stage (up to three years). They can be found in many types of water bodies from ephemeral pools to permanent lakes, ponds and flowing streams.
Treefrogs are relatively small anurans. They have a slim waist, long thin limbs and most have toes that terminate in distinctly enlarged discs or pads (except for the eastern cricket frog in Maryland). Treefrogs are distinguished from one another by a number of characteristics including, the type of dorsal markings they possess, the length of the back limbs, the presence or absence of a light spot under the eye and along the upper lip, and the size of the toepads.
There are a total of nine species of treefrogs in three genera that can be found in Maryland. Members of the three genera (Hyla, Pseudacris, and Acris) can be distinguished from one another using fairly obvious physical characteristics.
A number of documents were used to compile the species descriptions. Two documents provided the most information: Amphibians and Reptiles of Pennsylvania by Arthur C. Hulse, C. J. McCoy, and Ellen Censky (2001), which includes a key to tadpoles using features other than mouthparts. Amphibians and Reptiles of Delmarva by James F. and Amy Wendt White (2002), which provides descriptions of many features of tadpoles from Delmarva that can be used to distinguish species. These books are recommended to anyone seeking more comprehensive information on Maryland anuran ecology and identification.
In addition to physical descriptions of the anurans found in Maryland, maps depicting the distribution of each species in Maryland are also included. The distribution maps include historical distribution information that was compiled by Harris (1975). White and White (2002) also provided a great deal of the historical and recent distributional information for frogs and toads on Maryland’s eastern shore. Additional recent distribution information was provided by the Maryland Department of Natural Resources, Maryland Biological Stream Survey and Natural Heritage Program, and from additional literature where appropriate.
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