Acta Zoologica Cracoviensia, 16() 1971
A Comparative Study on the Morphological Characters of Adult Specimens of the Grass Frog Rana temporaria temporaria Linnaeus, 1758 and Moor Frog Rana arvalis arvalis Nilsson, 1842
Abstract:
Twenty-nine morphological and morphometrical characters, generally given in keys and descriptions and used to distinguish the grass frog from the moor frog, were studied. The author showed that only four of these characters are suitable for the correct determination of adult grass and moor frogs. These characters are the length ratio of the inner metatarsal tubercle to toe I, the development of the inner metatarsal tubercle, the shape of the snout, and the development of the longitudinal dorso-lateral folds. The use of these four characters alone visibly reduces the number of specimens considered to be hard to identify and treated by some authors as hybrids. The author denies the existence of such natural hybrids.
