''Macrokentriodon'' 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 ...

of giant

dolphin A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...

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 Extinction is the termination of an organism by the death of its End ...

. Remains have been found in the late

Miocene The Miocene ( ) is the first epoch (geology), 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 mea ...

(

Serravallian The Serravallian is, in the geologic timescale, an List of time periods, age or a stage (stratigraphy), stage in the middle Miocene epoch (geology), Epoch/series (stratigraphy), Series, which spans the time between 13.82 annum, Ma and 11.63 Ma (m ...

) Choptank Formation of

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. ''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'' and ''

Rudicetus ''Rudicetus'' is an extinct genus of cetacean. References Kentriodontidae Monotypic prehistoric cetacean genera Fossil taxa described in 2001 {{paleo-whale-stub ...

''.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

Kentriodontidae Miocene cetaceans Fossil taxa described in 1996 {{paleo-whale-stub