(a) Map of the major hominin sites mentioned in the text. The red pins indicate the occurrence of Crocuta crocuta ultima, and the blue pins Pachycrocuta brevirostris sinensis. The light green areas are the continental shelves 0–100 m below sea level. ‘Hexian etc.’=Hexian, Chaoxian and Tangshan. (b) The submarine topography around the Penghu Channel. The location of vertebrate fossil concentration in the Penghu Channel is encircled. The base map created using the GeoMapApp software (http://www.geomapapp.org/) and Global Multi-Resolution Topography synthesis69.