''Mergellus'' is a genus of duck. The

smew The smew (''Mergellus albellus'') is a species of duck and is the only living member of the genus ''Mergellus''. ''Mergellus'' is a diminutive of ''Mergus'' and ''albellus'' is from Latin ''albus'' "white". This genus is closely related to ''Me ...

''(Mergellus albellus)'' is the only living species, but an extinct species known as '' Mergellus mochanovi'' has also been described from

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

deposits in the

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region of

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. An unnamed

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

seaduck, known from a

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

found in the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

Sajóvölgyi Formation (Late Badenian, 13–12

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

) of

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was assigned to ''Mergus''. However, the authors included the smew therein, and consequently, the bone is more properly assigned to ''Mergellus''—especially as it was more similar to a smew's than to the ''Bucephala'' remains also found at the site. It is sometimes argued that the Mátraszõlõs fossil is too old to represent any of the modern seaduck genera, but apparently these were all well-distinct even back then.

References

{{Taxonbar, from=Q10792772 Bird genera with one living species Taxa named by Prideaux John Selby Anatinae