|Genetic and behavioral diversity in the Macrophthalmus japonicus species complex (Crustacea: Brachyura: Ocypodidae)|
Kitaura, J.; Nishida, M.; Wada, K. (2002). Genetic and behavioral diversity in the Macrophthalmus japonicus species complex (Crustacea: Brachyura: Ocypodidae). Mar. Biol. (Berl.) 140: 1-8
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
|Authors|| || Top |
- Kitaura, J.
- Nishida, M.
- Wada, K.
Two morphologically similar ocypodid crabs, Macrophthalmus japonicus and M. banzai, are distributed in East Asia from Japan to China, a disjunct population of the former also having been reported from western Australia. To clarify the genetic relationships among M. japonicus and M. banzai in East Asia and M. japonicus in Australia, a phylogenetic analysis was carried out based on nucleotide sequences of the mitochondrial 12S rRNA to16S rRNA genes (628 base pairs). The resultant tree revealed three major lineages, represented by M. banzai, Japanese and Korean M. japonicus, and Australian M. japonicus. The Australian M. japonicus lineage has diverged considerably from the other two lineages, having an evolutionary distance of 0.208 - 0.246, whereas the sequence divergence between East Asian M. japonicus and M. banzai ranged from 0.088 to 0.105. Although the waving display of Australian M. japonicus is performed in the same manner as in Japanese M. japonicus, other social behaviors, such as fighting and mating, differ somewhat. The genetic and behavioral differences strongly suggest that Australian M. japonicus is a distinct species, separate from East Asian M. japonicus. Among three M. banzai populations investigated, substantial genetic differentiation was observed, with Korean M. banzai being more divergent from two Japanese populations. Differences in waving display and some morphological characters also separate Korean M. banzai from Japanese M. banzai. Although the genetic divergence among these populations was at a level similar to those observed among other intraspecific crustacean populations, the overall differences suggest that Korean and Japanese M. banzai represent a complex of two species or subspecies.