Glossary of Herpetological Terms

Towards the front, or towards the head of the animal.
The carapace is the top part of the shell.
A smooth posterior margin of the carapace.
(Photo by J. Andrews)
A toothed posterior margin of the carapace.
(Photo by J. Andrews)
Dorsolateral ridges:
 The presence or absence of a dorsolateral ridge can be very helpful in the identification of a frog. The ridge is a fold of skin beginning behind the eye and extending part or all of the way to the rear legs on both sides.
(Photo by E. Talmage)
a reptile or amphibian.
The plastron is the underside of the shell.
(Photo by C. Fichtel)
Towards the back, or towards the tail of the animal.
keeled or smooth
Keeled scales have a ridge along the centerline of the scale.
Smooth scales do not have a ridge.
(Photo by J. Andrews)
A single plate or scale on a turtle’s shell.
The tympanum is the eardrum of a frog and in some species it can be seen very clearly. In the green-faced frogs (American Bullfrog, Green Frog, and Mink Frog) the size of the tympanum relative to the eye can be used to determine the sex of the animal. The males have tympana that are noticeably larger than their eyes. The female’s tympana are about the same size as their eyes.
 Male tympanum
 Female tympanum
(Photo of male frog by E. Talmage; photo of female frog by J. Andrews)