Deep-sea elasmobranchs from the late early to middle Miocene (Burdigalian–Langhian) Makino Formation (Awa Group), Japan

ABSTRACT

Thirteen elasmobranch genera, four of which are identified to species, are described from the early to middle Miocene (Burdigalian–Langhian) Awa Group in southwest Japan. Springeria and Narke are the first fossil records of these genera. Of these 13 genera, 10 have bathyal or pelagic Recent species. The deep-sea elasmobranch fauna of the Awa Group is characterized by dominance of Squalus species. The Awa fauna is clearly distinguished from the European Miocene fauna by the lack of abundant small sharks in Palaeocentroscymnus and Squaliolus.

ACKNOWLEDGMENTS

I would like to express my deepest gratitude to A. Ujihara (Graduate School of Environmental Studies, Nagoya University) for his exceptional contributions to all aspects of this research—from sample collection to discussions at various stages. I especially thank Y. Iryu (Institute of Geology and Paleontology, Graduate School of Science, Tohoku University); I. Suto, S. Hayashi, and M. Humblet (Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University); and T. Oji, S. Nishida, and S. Fujiwara (Nagoya University Museum) for their many helpful suggestions. In addition, I thank T. Ichihara (College of Nagoya Bunri University) for providing information on fossil localities, as well as K. Sato (Okinawa Churashima Research Center) and S. Tanaka (School of Marine Science and Technology, Tokai University) for arranging for inspection of specimens of modern species and for their useful comments on the taxonomy of Scyliorhinidae and Squaliformes. I also thank two anonymous reviewers for their constructive reviews and helpful comments.