Mancallinae is an extinct subfamily of prehistoric flightless alcids that lived on the Pacific coast of today's California and Mexico from the late Miocene epoch to the early Pleistocene (ranging from at least 7.4 million to 470,000 years ago).

They had evolved along somewhat similar lines as the great auk, their North Atlantic ecological counterpart, but their decidedly stubbier wings were in some aspects more convergent with penguins.

Alcodes is known from a single ulna found in Late Miocene (Clarendonian, 9–12 mya) deposits at Laguna Hills, California.

This coincided with the diversification of marine mammals, but may ultimately have been caused by increased supernova activity in the vicinity of the solar system.

[7] Despite their apparent awkwardness, they seem to have been quite well adapted for flightless birds, with the fossil record suggesting that the last remnants did not disappear until the Early Pleistocene,[citation needed] some time after the ecological changes had passed their peak.