Deep-sea fish otoliths from the Lower Miocene Oi and Katada formations, Ichishi Group, Mie Prefecture, central Japan

ABSTRACT

Fish otoliths from the Lower Miocene Oi and Katada formations, Ichishi Group, central Japan, were examined, and a total of 894 specimens were obtained, of which 523 were assigned to 21 otolith-based taxa belonging to 10 families. All taxa other than Gobiiformes indet. are considered to be from deep-sea fishes. One species of the family Phosichthyidae and two species of the family Myctophidae are new: Vinciguerria rotunda sp. nov. Myctophum isense sp. nov. and Diaphus ichishiensis sp. nov. This is the first report in the world of the genus Cyclothone as a fossil otolith. The occurrence of the genus Poromitra constitutes the oldest fossil record in the Pacific. The family Myctophidae is predominant throughout the studied sections, and the family Phosichthyidae was found commonly in the Katada Formation (uppermost formation of this group). At the family level, the main components of the otolith-based fossil ichthyofauna in the Katada Formation are composed of taxa dominating even in the modern open ocean. The Early Miocene deep-sea fish otolith fauna in the Northwest Pacific is characterised by the overwhelming predominance of the genus Diaphus as well as the presence of the genera Vinciguerria, Myctophum, Protomyctophum and Stenobrachius as significant components.

LSID of ZooBank zoobank.org:act:720791A1-BFC4-4E80-90C2-C018D4AF506F

LSID of ZooBank zoobank.org:act:918F452A-50BD-4012-B590-3199AC9838A4

LSID of ZooBank zoobank.org:act:0BE69125-ED11-4C41-815D-2B8FA9B260E5

KEYWORDS:

• Otolith
• Deep sea fish
• Northwest Pacific
• Early Miocene
• Taxonomy
• Fauna

Acknowledgments

We greatly thank Seiji Hayashi (Nagoya University, Japan) for advising us on how to use the scanning electron microscope and Koki Nishimatsu (Nagoya University, Japan) for helping collect rock samples. We are grateful for helpful comments from the members of the Laboratory of Geology and Geobiology, Nagoya University, Japan. Our manuscript has been greatly improved by the revisions of Gary L. Stringer (University of Louisiana at Monroe, USA) and Chien-Hsiang Lin (Biodiversity Research Center, Academia Sinica, Taiwan).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financially supported by JST SPRING, Grant Number [JPMJSP2125] to Yuki Tsuchiya.