Coot fossils from the Middle Pleistocene of California have been described as "Fulica hesterna" but cannot be separated from the present-day American coot. However, the Pleistocene coot "Fulica shufeldti" (formerly "F. minor"), famously known as part of the Fossil Lake fauna, quite possibly was a paleosubspecies of the American coot (as "Fulica americana shufeldti") as they only differed marginally in size and proportions from living birds. Thus, it seems that the modern-type American coots evolved during the mid-late Pleistocene, a few hundred thousand years ago.