Whale barnacles and Neogene cetacean migration routes

An exceptional fossil assemblage of the ectoparasitic whale barnacle Coronula diadema was recently discovered from late Pliocene-Pleistocene sediments outcropping on the coast of Ecuador where today humpback whales (Megaptera novaeangliae) migrate for breeding. A similar occurrence is recorded in New Zealand and in Vanuatu, where late Pliocene-Pleistocene fossil coronulids have been found in sediments along the coasts that are current humpback whale migration routes. In both Ecuador and New Zealand we have collected fragmentary whale remains in association with these barnacle assemblages. Considering that detachment of whale barnacles from extant humpback whales has only been observed in breeding areas or along migratory routes, we view the Ecuador and New Zealand fossil barnacle assemblages as indirect evidence of whale migration during the late Neogene. Application of this hypothesis to the distribution pattern of fossil Coronula in the Mediterranean Basin, indicates that, unlike the present, mysticete whales may have used the Mediterranean as a breeding ground during the Pliocene and Pleistocene.