Pygoscelis
The genus Pygoscelis contains three living species of penguins collectively known as "brush-tailed penguins".
Taxonomy
suggests the genus split from other penguins around 38 million years ago, about 2 million years after the ancestors of the genus Aptenodytes. In turn, the Adelie penguins split off from the other members of the genus around 19 million years ago.;Extant species
A 2020 study found that the gentoo penguin may actually comprise a species complex of 4 similar but genetically distinct species: the northern gentoo penguin, the southern gentoo penguin, the eastern gentoo penguin, and the newly-described South Georgia gentoo penguin. However, in 2021 the International Ornithological Congress recognized these as being subspecies of P. papua.
A study has estimated that there are about 3.79 million pairs of Adélie, 387,000 pairs of gentoo, and 8 million pairs of chinstrap penguins in their particular areas, making up 90% of Antarctic avian biomass.
;Fossil species
The latter two are tentatively assigned to this genus.