Morphology and phylogenetic relationships of a new eschrichtiid genus (Cetacea: Mysticeti) from the Early Pliocene of northern Italy

A new eschrichtiid, Eschrichtioides gastaldii gen. nov., comb. nov., is established based on a specimen previously assigned to Balaenoptera gastaldii Portis, 1885. The holotype is from the Early Pliocene of north-east Italy. It represents a fossil mysticete closely related to the living grey whale, Eschrichtius robustus. Comparative morphology and phylogenetic analysis support the monophyly of Eschrichtiidae and Cetotherium-like mysticetes and a sister group relationship between this clade and Balaenopteridae. Eschrichtiid fossils previously described are all from the Pleistocene and Late Pliocene while Eschrichtioides gastaldii is from the Early Pliocene. The recognition of this new eschrichtiid genus suggests that the Mediterranean trophic web of the Early Pliocene was more complex than at present and that the Neogene mysticete family-level biodiversity of the Mediterranean was higher than that currently observed in this basin.