Ichthyological Research

, Volume 49, Issue 4, pp 333–339 | Cite as

A new lentic form of the “yoshinobori” species complex, Rhinogobius spp. from Lake Biwa, Japan, compared with lake–river migrating Rhinogobius sp. OR

  • Sachiko Takahashi
  • Toshio Okazaki


 The various life history strategies seen within the “yoshinobori” species complex of the genus Rhinogobius, which differentiated from an amphidromous ancestor, have been grouped ecologically into amphidromous, fluvial, and lacustrine types. In the Lake Biwa water system, two lacustrine forms exist, a newly discovered, exclusively lentic form and the already well known Rhinogobius sp. OR, which generally undergoes lake–river migration but also includes lentic individuals that share spawning grounds with the former lentic form. Detailed morphological comparisons and allozyme analysis revealed consistently clear differences between the two forms, indicating them to be distinct species. The newly discovered lentic form has many distinctive morphological features that enable it to be distinguished from sympatric Rhinogobius sp. OR: dwarfness, short snout, longitudinally slender pelvic fin, undeveloped frenum with a low lamella, low first dorsal fin in adult males, lesser caudal peduncle depth, scaleless predorsal and ventral areas, and incomplete sensory canals. The lentic form was temporarily named Rhinogobius sp. BW. The life history patterns of the lake-inhabiting populations were separated into two categories: a lake–river migratory lifestyle and an exclusively lentic lifestyle.

Key words Freshwater gobies Rhinogobius Lake Biwa Allozyme Morphology 


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Copyright information

© The Ichthyological Society of Japan 2002

Authors and Affiliations

  • Sachiko Takahashi
    • 1
  • Toshio Okazaki
    • 2
  1. 1. 13-1 Shimomiyamae-cho, Shishigatani, Sakyo, Kyoto 606-8431, Japan (e-mail: aas12610@par.odn.ne.jp)JP
  2. 2. National Research Institute of Aquaculture, Hiruta, Tamaki-cho, Mie 519-0423, Japan (e-mail: okazakit@fra.affrc.go.jp)JP

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