Geographic distribution and biogeographical origin of the spined loach genus Cobitius in north-eastern Kyushu Island, Japan

Abstract

In order to clarify the distribution pattern of three Japanese spined loach species’ complexes in the genus Cobitis (‘yamato’, biwae, and striata complexes) in north-eastern Kyushu Island, 106 specimens obtained from 19 drainage systems were morphologically and genetically examined. Although that region has been previously considered occupied only by the ‘yamato’ complex, some populations of the biwae and striata complexes were confirmed, the distribution patterns being explained by the paleo-Setouchi drainage pattern during the most recent Pleistcene glacial periods. Distinctive populations within the middle race of striata complex included 2 new local forms in Fukuoka Prefecture (the Setouchi form, Hakata form and Onga form).