Indo-West Pacific biogeographic research and speciation among Amphibalaninae

Prabowo RE 1 and T Yamaguchi 2

1 Faculty of Biology, University of Jenderal Soedirman, Purwokerto, Indonesia
2 Department of Earth Sciences, Graduate School of Science, Chiba University, Chiba, Japan

Four barnacle regions were recognized in Indo-West Pacific i.e.; Indo-Malayan, Eastern Indonesian (including Okinawa), Southern and Eastern Australian and New Zealand. Species contribution values suggest that all regions dominated by Amphibalaninae especially Indo-Malayan and Eastern Indonesian. The origin of those two barnacle regions relates closely to the paleo-coastlines before Plio-Pleistocene sea level changes. Some new morpho-species revealed in this study, i.e.: F. sumbawaensis, a new species from Indo-Malayan region and two new species from Eastern Indonesian region. The taxonomic position of two distinct populations of the Amphibalanus variegatus from Asia and Australia has also been corrected, and elevated Asian population as a new species. The works of Harding (1962) and Henry & McLaughlin (1975) on A. variegatus showed a slightly different morphological description, since each of them referred to two different populations mentioned above. Fistulobalanus kondakovi has also been reported to occur in Australia apart from its typical population in Japan due to some morphological similarity to Australian A. variegatus. A work on these two species including 8 other amphibalanids on historical taxonomy, morphology, biogeography, and phylogeny, was performed to solve their correct species assignment. This research compared 14 populations; of which 5 represent Asian A. variegatus, 5 Australian A. variegatus, and 5 Asian F. kondakovi. The molecular evidence based on COI gene sequences showed there are five lineages of this two species. The phylogram shows deep split branching of those 5 lineages. Pairwise genetic distances and genetic differences values suggest those 5 lineages are significantly distinct species. Australian populations of A. variegatus differ to their Asian sister and assigned as true A. variegatus. Asian populations previously known as A. variegatus elevated as new species, of which 1 population from Indonesia is a cryptic species.