A Neogene bristlemouth of the genus Cyclothone (Stomiiformes: Gonostomatidae) from South Korea

ABSTRACT

A fossil specimen of bristlemouth fish of the genus Cyclothone is reported for the first time from the marine deposits of the middle Miocene Duho Formation, South Korea, and described as new species Cyclothone duhoensis, sp. nov. This is the second stomiiform fish discovered there. It represents the oldest nominal species of its genus, and the third and southernmost record of fossil bristlemouth from the ancient Eastern Sea (Sea of Japan) basin after the findings in the Sakhalin (Russia) and Honshu (Japan) islands. The new Miocene bristlemouth is very similar to the Recent congeners. Nevertheless, it can be separated from them by the presence of more than 15 photophores in the AC series, of which at least four photophores are behind the anal-fin base, and by a peculiar upper jaw dentition. The biological features of the Recent bristlemouths along with this unique finding hint at shallow-water conditions during the Duho Formation sedimentation.

KEYWORDS:

• Bristlemouth
• Cyclothone
• new species
• Stomiiformes
• Serravallian
• South Korea

Acknowledgments

We would like to express our sincere thanks to M.V.H. Wilson (University of Alberta, Canada) and two anonymous reviewers for their valuable comments and corrections which greatly improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The reported study was funded by RFBR and National Research Foundation of Korea according to the research project № 19-54-51001 and under the framework of international cooperation program managed by the National Research Foundation of Korea [2019K2A9A1A0609922511].