-aged
Green River Formation Amia is thought to have diverged from its
sister genus,
Cyclurus, during the
Late Cretaceous. These two genera, their sister amiine
Pseudoamiatus, and the marine
vidalamiine Maliamia were the only amiids, and
halecomorphs as a whole, to survive the
Cretaceous-Paleogene extinction event. During this time period, some species of
Amia evolved very large body sizes, most notably
A. basiloides, which is one of the largest
holosteans known to have existed. In contrast to the modern distribution of
Amia, most of these fossils are from western North America.
Species List of species. •
Amia basiloides Brownstein & Near, 2024 (middle
Paleocene of Montana, USA) •
Amia pattersoni Grande & Bemis, 1998 (late Paleocene of Alberta, Canada) •
Amia scutata Cope 1875 (late Eocene of Colorado, USA) The species
Amia uintaensis Leidy, 1873, which formerly contained several
Amia specimens from western North America dating from the Late Cretaceous to the Eocene (including the holotype of
A. basiloides), is considered a
nomen vanum. Another large Paleocene amiid,
Amia robusta Smith & Radcliffe, 1911 from France, is known from non-diagnostic remains, and is thus considered a
nomen dubium. Possibly the oldest known species in the genus is
Amia limosa from the Late Cretaceous-aged
Bissekty Formation of
Uzbekistan, for which it is the most abundant fossil fish. This species was considered a
nomen dubium in a 1998 study, but a 2025 study retained it as a valid taxon, noting its distinguishing features from the related, concurrent
Cyclurus fragosus of North America. It was also tentatively retained in
Amia pending further research. ==References==