Ichthyological Research

, Volume 57, Issue 1, pp 71–77 | Cite as

Cryptic diversification of the swamp eel Monopterus albus in East and Southeast Asia, with special reference to the Ryukyuan populations

  • Seiji Matsumoto
  • Takeshi KonEmail author
  • Motoomi Yamaguchi
  • Hirohiko Takeshima
  • Yuji Yamazaki
  • Takahiko Mukai
  • Kaoru Kuriiwa
  • Masanori Kohda
  • Mutsumi Nishida
Full Paper


The swamp eel Monopterus albus is widely distributed in tropical and subtropical freshwaters ranging from Southeast Asia to East Asia, and is unique in its ability to breathe air through the buccal mucosa. To examine the genetic structure of this widespread species, molecular phylogenetic analyses of mitochondrial 16S rRNA sequence (514 bp) were conducted for 84 specimens from 13 localities in Southeast and East Asia. The analyses showed clearly that this species can be genetically delineated into three clades based on geographical populations [China–Japan (Honshu + Kyushu), Ryukyu Islands, and Southeast Asia clades], with each clade exhibiting its own reproductive behavior. Therefore, “M. albus” is believed to be composed of at least three species. The Southeast Asia clade with the highest genetic diversity may include more species. The Ryukyu clade was estimated to have diverged more than 5.7 million years ago, suggesting that the Ryukyuan “M. albus” is native. In contrast, in the China–Japan clade, all haplotypes from Japan were closely related to those from China, suggesting artificial introduction(s).


Monopterus albus Ryukyu Islands Mitochondrial DNA Endemic species Artificial introduction(s) 



We thank H. Fujimoto (Yaeyama Agriculture and Forestry High School), K. Takehara (Okinawa Prefectural Museum), F. Sato (Kumejima Firefly Pavilion), and M. Taira (Ishigaki City Office) for their cooperation with the collection of specimens in the Ryukyu Islands. We are also grateful to B. Ridersius (Murakabi Biana K. K.) for helping with the sampling in Yogyakarta, as well as to C.S. Tzeng (National Tsing Hus University) and T.L. Tao (Taiwanese Freshwater Fish Museum) for their help with sampling in Taiwan. We also thank two anonymous reviewers for their constructive comments aimed at improving the manuscript. This study was supported in part by grants-in-aid for the Encouragement of Scientists awarded to S.M. (17916021) and for Scientific Research to M.N. (15380131, 19207007) by the Japan Society for the Promotion of Science.


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Copyright information

© The Ichthyological Society of Japan 2009

Authors and Affiliations

  • Seiji Matsumoto
    • 1
  • Takeshi Kon
    • 2
    Email author
  • Motoomi Yamaguchi
    • 2
  • Hirohiko Takeshima
    • 2
  • Yuji Yamazaki
    • 2
    • 4
  • Takahiko Mukai
    • 2
    • 5
  • Kaoru Kuriiwa
    • 2
    • 6
  • Masanori Kohda
    • 3
  • Mutsumi Nishida
    • 2
  1. 1.Kashihara City Museum of InsectNara634-0024Japan
  2. 2.Department of Marine Bioscience, Ocean Research InstituteThe University of TokyoTokyoJapan
  3. 3.Department of Biology and Geosciences, Graduate School of ScienceOsaka City UniversityOsakaJapan
  4. 4.Department of Biology, Faculty of ScienceUniversity of ToyamaToyamaJapan
  5. 5.Department of Regional Policies, Faculty of Regional StudiesGifu UniversityGifuJapan
  6. 6.National Museum of Nature and ScienceTokyoJapan

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