Reptile Glossary
Allopatric: A term applied to two or more populations that occupy mutually exclusive, but usually adjacent, geographical areas.
Ambient temperature: The temperature of the environment surrounding the animal in question.
Aquatic: Frequenting water, or living or growing in water. Technically, only animals that have gills for extracting oxygen from water are aquatic, whereas others, such as turtles and water snakes, are semiaquatic.
Attenuated: Thin or slender.
Azygous: Odd, not paired.
Barbels: Small, fleshy, usually downward projections of skin on the chin and/or throat (in some kinds of turtles and the tadpoles of the Mexican Burrowing Toad).
Boss: A raised, rounded area, in toads, a rounded eminence on the midline of the head between the eyes or on or near the end of the snout.
Canthus rostralis: The ridge from the eye to the tip of the snout that separates the top of the muzzle from the side.
Carapace: The upper shell of a turtle.
Cirri: Downward projections from the nostrils in males of certain lungless salamanders. The naso-labial groove extends downward to near the tip of each cirrus.
Cline: A gradual change in a variable characteristic.
Cloaca: The common chamber into which the urinary, digestive, and reproductive canals discharge their contents, and which opens to the exterior through the anus.
Costal grooves: Vertical grooves on the flanks of salamanders. The spaces between grooves are called coastal folds.
Cranial crests: The raised ridges on the heads of toads -- interorbital (between the eyes) or postorbital (behind the eyes).
Crepuscular: Active at twilight and/or dawn.
Cusp: A toothlike projection on the jaw of a turtle.
Cuspate: Possessing an enlarged point at the middle of the upper jaw (in certain tadpoles and turtles).
Dimorphism: Difference in form, color, or structure between members of the same species. The sexes may be different or there may be two color phases of the same sex (dichromatism).
Dorsal: Of or pertaining to the upper surface.
Dorsal gap: The area above the upper lip of tadpoles where the oral disc ends.
Dorsolateral: Neither directly down the center of the back nor at the side of the body, but more or less intermediate between the two.
Dorsum: The entire upper surface of an animal.
[Conant, Roger and Collins, Joseph T., Peterson Field Guides Reptiles and Amphibians, Houghton Mifflin Company, Boston, 1975]