GEOGRAPHICAL VARIATIONS OF RANA-SAUTERI (ANURA, RANIDAE) IN TAIWAN

Rana sauteri is widely distributed in hills and mountains of Taiwan fr om 100 to 3000 m in elevation, a range including subtropical to cool t emperate climatic zones. Both the gastromyzophorous tadpoles and adult s have distinct geographical variations in morphology. Clinal variatio n in the shape of the upper jaw sheath and the number of labial tooth rows occurs from the foothills of western Taiwan eastward through the Central Mountain Range to the eastern slopes of the Central Mountain R ange. This geographical pattern is supported and validated by multivar iate analyses of adult morphology. According to the dispersal hypothes is, this geographical pattern may suggest that the dispersal center (= initial range of the ancestral group) was located in the western foot hills, and it may indicate that the population expanded radially throu gh the clinally variable transition zone to areas adjacent to the ridg e of the Central Mountain Range (= range of the derived group). Howeve r, the establishment of the geographical pattern of R. sauteri seems t o be better explained by the vicariance hypothesis which supports the occurrence of isolation-based dichotomous divergence within this gross ly defined taxon.