Paleontological Studies of Whale Barnacles in Taiwan Reveal New Cetacean Migration Routes in the Western Pacific Since the Miocene.

This paper reports a rediscovery of the first museum specimens of fossil whale barnacles from Taiwan. They are part of the material studied and figured by Ichiro Hayasaka in 1934. After examination of the material, which includes two cut-sections and one slice, the taxonomic assignment is revised to Coronula bifida Bronn, 1831. A petrographic study of the surrounding matrix shows that the matrix lacks slate and lithic fragments, indicating that the specimen was deposited in the pre-collision settings during the Miocene to early Pliocene. Figured specimens in Hatai's work in 1939 were examined for comparison. The distribution record of Coronula fossils shows that whales passed through the Taiwan Strait to Okinawa and moved northwards via the Pacific coast of Honshu or entered into the Sea of Japan. The fossil record in this region extends back to the upper Miocene in Yamagata prefecture (facing the Sea of Japan) and Boso Peninsula (facing the Pacific Ocean) in Honshu (~11.2 Ma-5.3 Ma). This is one of the oldest cetacean migration routes documented to date.