Atocetus

Atocetus is an extinct genus of pontoporiid dolphin found in Miocene-age marine deposits in Peru and California.
Description.
The type species, "Atocetus iquensis", is known from Serravallian-age strata of the Pisco Formation of Peru, while "A. nasalis" is known from Tortonian-age marine deposits in California. Barnes (1985) originally described the latter as a species of "Pithanodelphis", but it was eventually transferred to "Atocetus" by Muizon (1988). The Miocene delphinidan ""Champsodelphis" fuchsii" from marine deposits in Austria was initially tentatively referred to "Atocetus" based on the discovery of partial skeletons from the Carpathian region with earbones similar to those of "Atocetus" but was eventually re-assigned to "Kentriodon" following the discovery of additional earbones from Austria and Romania.
Phylogeny.
Although "Atocetus" and other pithanodelphinines are usually assigned to Kentriodontidae, the cladistic analysis of Lambert et al. (2017) showed that "Atocetus" and "Pithanodelphis" form a clade with "Tagicetus" and "Lophocetus" that is not only phylogenetically more derived than other kentriodontids but is also phylogenetically intermediate between the baiji and members of Inioidea and Phocoenidae. However, a subsequent cladistic analysis by Post et al. (2017) recovers "Atocetus" as a member of Pontoporiidae, which includes the franciscana. 