Marine Biology

, Volume 149, Issue 4, pp 875–883

Hidden ancient diversification in the circumtropical lancelet Asymmetron lucayanum complex


    • Department of Marine Bioscience, Ocean Research InstituteThe University of Tokyo
  • M. Nohara
    • Yokohama R&D CenterHITEC Co., Ltd
  • M. Nishida
    • Department of Marine Bioscience, Ocean Research InstituteThe University of Tokyo
  • W. Sterrer
    • Bermuda Natural History Museum
  • T. Nishikawa
    • The Nagoya University MuseumNagoya University
Research Article

DOI: 10.1007/s00227-006-0271-y

Cite this article as:
Kon, T., Nohara, M., Nishida, M. et al. Mar Biol (2006) 149: 875. doi:10.1007/s00227-006-0271-y


The tropical lancelet Asymmetron lucayanum (= Epigonichthys lucayanus) is distributed from the western Indian Ocean to the central Pacific Ocean, and the western Atlantic Ocean. Molecular phylogenetic analysis of mitochondrial cytochrome c oxidase subunit I (COI) sequences (1,035 bp) of A. lucayanum (80 specimens from seven localities) showed clearly that this species is genetically distinguished into three major groups of geographical populations based on neighbor-joining tree using maximum likelihood distance (HKY model with invariable sites and gamma correction), suggesting the existence of three cryptic species. Our genetic data show that (1) inter-oceanic divergence time between Clade B (the West-Central Pacific) and Clade C (the Atlantic) (d = 6.6%, ca. 12 million years ago) was smaller than intra-oceanic divergence time between Clade A (the Indo-West Pacific) and Clade B (d=39.5%, ca. 100 million years ago); (2) there are two cryptic species in the West Pacific in sympatry; and (3) high gene flow is implied between the Maldives and the Ryukyus in Clade A (10,000 km distance), the Philippines and Hawaii in Clade B (8,500 km distance), and Barbados and Bermuda in Clade C (2,200 km distance).

Copyright information

© Springer-Verlag 2006