plural noun
Mar·​su·​pi·​on·​ta | \märˌsüpēˈäntə\

Definition of Marsupionta 

in some classifications

: a subclass of mammals coextensive with the Prototheria and Metatheria and comprising all the nonplacental mammals

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History and Etymology for Marsupionta

New Latin, from Marsupialia + Greek -onta (nominative neuter plural participial ending)

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