Data for: Hidden population turnover of small odontocetes in the northwestern North Pacific during the Holocene

Despite numerous studies on the rise and fall of terrestrial megafauna in
the Late Quaternary, knowledge about marine megafauna from this period
remains limited. In this study, we performed radiocarbon dating and
partial mitochondrial DNA sequencing from the skeletal remains of three
species of small odontocetes (Pacific white-sided dolphins, Dall’s
porpoises, and harbour porpoises) excavated from prehistoric
archaeological sites around the Japanese shore dating back to 8500 – 1000
years ago (ya). Pacific white-sided dolphins that habituated the eastern
coast of Hokkaido around 2000 ya belonged to different maternal groups
than those from over 5000 ya and today. Furthermore, the species
composition excavated from eastern Hokkaido sites varies between 5000 and
2000 ya. These findings suggest two significant population turnovers of
small odontocetes on the east coast of Hokkaido, a transitional zone
between the coastal area of East Asia and the offshore North Pacific.
Notably, the first turnover, occurring between 5000 and 2000 ya,
represents the oldest evidence of local population turnovers of marine
megafauna during the Late Quaternary.