''Phocageneus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

river dolphin River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant rive ...

belonging to

Squalodelphinidae Squalodelphinidae is a family of primitive platanistoid river dolphins, found in marine deposits in the eastern Pacific, western Atlantic, and Europe. Description Distinguishing features of Squalodelphinidae include a moderately elongated and t ...

. Specimens have been found in the middle Miocene

Calvert Formation The Calvert Formation is a Formation (geology), geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene, Miocene epoch of the Neogene Period (geology), period. It is one of the three ...

of Maryland and Virginia.

References

{{Taxonbar, from=Q49001330 Squalodelphinidae Miocene cetaceans Monotypic prehistoric cetacean genera Miocene mammals of North America Paleontology in Maryland Paleontology in Virginia Fossil taxa described in 1869 Taxa named by Joseph Leidy