<i>Scaphokogia totajpe</i>, sp. nov., a new bulky-faced pygmy sperm whale (Kogiidae) from the late Miocene of Peru

The modern pygmy and dwarf sperm whales (Physeteroidea, Kogiidae) are remnants of a highly diverse group, which flourished in the Miocene oceans. Unlike their modern suction-feeding, deep-diving relatives, the past diversity of this family includes animals with disparate ecological habits. Here, we describe <i>Scaphokogia totajpe</i>, sp. nov., a new species of kogiid based on a well-preserved skull from the upper Miocene strata of the Pisco Formation, Peru. A phylogenetic analysis places <i>S</i>. <i>totajpe</i> as sister taxon of <i>S</i>. <i>cochlearis</i> and divides Kogiidae into two clades: the first including both species of <i>Scaphokogia</i> and the second including <i>Kogia</i>, <i>Koristocetus</i>, <i>Praekogia</i>, and <i>Nanokogia</i>. Similar to <i>S. cochlearis</i>, <i>S. totajpe</i> has a tubular rostrum with a hypertrophied mesorostral canal, a large supracranial basin, and a leftward deviated facial sagittal crest, but it differs by possessing a proportionately shorter rostrum, a reduced projection of the lacrimojugal between the frontal and the maxilla, and a flat occipital shield. The cranial morphology of <i>Scaphokogia</i> indicates that the extent of the nasal complex was greater than in modern kogiids. Furthermore, the overall rostrum shape and the reconstructed muscle insertion sites indicate that <i>Scaphokogia</i> retained some plesiomorphic features related to a more generalist ecology. Inclusion of <i>S</i>. <i>totajpe</i> into the context of the Pisco Formation indicates that during the late Miocene, the Peruvian coastal system was a hot spot for the diversification of physeteroids, with at least four species coexisting. Finally, <i>Scaphokogia totajpe</i> highlights a late Miocene diversity peak for sperm whales in the global oceans, before the Pliocene odontocete turnover.