''Macrokentriodon'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of giant

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...

once assigned to the paraphyletic/polyphyletic family

Kentriodontidae Kentriodontidae is an extinct family of odontocete whales related to modern dolphins. The Kentriodontidae lived from the Oligocene to the Pliocene before going extinct. Taxonomy Kentriodontids have been variously divided into three or four sub ...

. Remains have been found in the late

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

(

Serravallian The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Tortonian ...

) Choptank Formation of

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. ''Macrokentriodon'' is similar to ''

Hadrodelphis ''Hadrodelphis'' is an extinct genus of dolphin once assigned to the paraphyletic/polyphyletic family Kentriodontidae. Remains have been found in the middle Miocene (Langhian) Calvert Formation of United States. Taxonomy ''Harodelphis'' is simil ...

'' in its larger size and its large tooth diameter. Despite being traditionally assigned to Kentriodontidae, recent cladistic analyses have recovered it along with ''Hadrodelphis'' in a clade with '' Kampholophos'' as sister to crown Delphinida and more derived than ''

Kentriodon ''Kentriodon'' is an extinct genus of Odontoceti, toothed whale related to modern-day dolphins. Fossils have been found in North America, Europe and Japan. Several species have been described. Description ''Kentriodon'' was the most diverse ...

'' and '' Rudicetus''.Post K, Louwye S, Lambert O. (2017) Scaldiporia vandokkumi, a new pontoporiid (Mammalia, Cetacea, Odontoceti) from the Late Miocene to earliest Pliocene of the Westerschelde estuary (The Netherlands) PeerJ 5:e3991 https://doi.org/10.7717/peerj.3991

References

Prehistoric toothed whales Miocene cetaceans Fossil taxa described in 1996 {{paleo-whale-stub