DISTRIBUTION, VARIATION, AND SYSTEMATICS OF THE SEYCHELLES TREEFROG, TACHYCNEMIS-SEYCHELLENSIS (AMPHIBIA, ANURA, HYPEROLIIDAE)

The endemic Seychelles treefrog, Tachycnemis seychellensis (Dumeril & Bibron), is restricted to four of the granitic islands of the Seychell es: La Digue, Mahe, Praslin and Silhouette. Megalixalus infrarufus Gun ther 1869 is a junior synonym of Eucnemis (Tachycnemis) seychellensis Dumeril Bibron, 1841. Significant variation in colour and morphometric characteristics exists within and between island populations. The pat terns of geographic variation revealed support the hypothesis that the distribution of Tachycnemis seychellensis in the granitic Seychelles reflects vicariance through fragmentation of the Seychelles Microconti nent 10,000 years B. P. by marine transgression. However, the possibil ity of low rates of postfragmentation dispersal between islands cannot be ruled out, The close relationship of the nearby Mahe and Silhouett e populations probably reflects prefragmentation gene flow over relati vely short distances and postfragmentation stasis due to large populat ion size and similar environments. The small body size and colour simi larities of the Praslin and La Digue populations may result of genetic drift and strong selection. It is argued that the four island populat ions represent a single species and that subspecies should not be name d.