HYBRIDIZATION EXPERIMENTS IN ACHEILOGNATHINE FISHES (CYPRINIDAE, TELEOSTEI): FERTILE INTRAGENERIC HYBRIDS BETWEEN FEMALE ACHEILOGNATHUS LANCEOLATUS AND MALE ACHEILOGNATHUS LIMBATUS FROM JAPAN

The presence of gametic and genomic compatibility between female Acheilognathus lanceolatus and male Acheilognathus limbatus (of Japanese origin) has been established experimentally. The F1 hybrid offspring which were obtained from this combination consisted mainly of fertile males and females, and interbreeding yielded viable larvae. When crossed back to the maternal species, A. lanceolatus, the male and female F1 hybrids gave birth to F2 progenies which again consisted mainly of males and females and were interfertile. Although both species of bitterling are sympatric in Japan, the occurrence of natural hybrids has so far not been reported. Some factors which, theoretically, could promote or counteract introgression of both species in their natural habitat are briefly discussed.