Geographical Differentiation in a Japanese Stream-Breeding Frog, Buergeria buergeri, Elucidated by Morphometric...

Hiroshima and Aomori populations of Buergeria buergeri (hereinafter abbreviated as HIROSHIMA and AOMORI, respectively) were morphologically differentiated in both sexually matured frogs and tadpoles. The mean snout-vent lengths of females were 67.4 mm in HIROSHIMA and 50.4 mm in AOMORI, and those of males were 42.9 mm in HIROSHIMA and 37.2 mm in AOMORI. The mean body weights of females of HIROSHIMA and AOMORI just after spawning were 18.0 g and 7.2 g, and those of males of HIROSHIMA and AOMORI were 4.9 g and 3.8 g, respectively. AOMORI tadpoles were rather stocky and their appearance seemed to be more adaptive to lentic water than HIROSHIMA tadpoles. The lower lip of the tadpoles at stage XIII consisted of 2 continuous and 1 broken teeth rows in HIROSHIMA, whereas 3 continuous and 1 broken ones in AOMORI. The growth rate of the embryos was higher in AOMORI than in HIROSHIMA. The embryos of AOMORI were more tolerant to high temperature and less tolerant to low temperature than those of HIROSHIMA. Hybrids between these two populations showed considerably reduced viability in either combination of reciprocal crosses.