First in-situ find of the whale barnacle Coronula bifida Bronn, 1831 from the Early Pleistocene of The Netherlands

Whale barnacles (Cirripedia: Coronulidae) are acorn barnacles that live exclusively on the skin of whales. They are rare in the fossil record. Here, we describe an incomplete rostrum as the first stratigraphically constrained specimen of Coronula bifida Bronn, 1831 and indeed any fossil whale barnacle from The Netherlands. It was found in a sediment sample from a borehole, originating from 161-164 metres below the surface level of the centre of Rotterdam. It originates from the Maassluis Formation, which can be assigned an Early Pleistocene (c. 1.8-2.4 Ma) age. Its occurrence suggests that a balaenopterid whale species was present in the North Sea Basin during the Early Pleistocene, which constitutes the first (indirect) evidence for the occurrence of baleen whales in the Southern North Sea at that time