Formerly, this group was thought to be even more diverse than it is thought to be now, containing about 41% of all
bony fish (about 10,000 species) and about 160 families, which is the most of any order within the vertebrates. However, many of these other families have since been reclassified within their own orders within the clade Percomorpha, significantly reducing the size of the group. In contrast to this splitting, other groups formerly considered distinct, such as the
Scorpaeniformes, are now classified in the Perciformes.
Evolution The earliest fossil perciform is the extinct
stem group-perciform
Paleoserranus (originally considered an early
serranid) from the
Early Paleocene of
Mexico, but potential records of "percoids" are known from the
Maastrichtian, including
Eoserranus and
Prolates, although their exact taxonomic identity remains uncertain. The earliest crown-group perciform fossils are known from the
Early Eocene, including the
scorpaenoid Eosynanceja and
platycephalid otoliths from New Zealand.
Present classification The following classification is based on ''
Eschmeyer's Catalog of Fishes'': • Family
Hemilepidotidae Jordan & Evermann, 1898 (Irish lords) • ?Family †
Callipterygidae Jordan, 1905 • ?Family †
Eocottidae Bannikov, 2004 • ?Family †
Robertanniidae Bannikov, 2011 • Family †
Trispinachidae Nazarkin, 2002
Past classifications As traditionally defined before the introduction of
cladistics, the Perciformes are almost certainly
paraphyletic. Other orders that should possibly be included as suborders are the
Scorpaeniformes,
Tetraodontiformes, and
Pleuronectiformes. Of the presently recognized suborders, several may be paraphyletic, as well. These are grouped by suborder/superfamily, generally following the text
Fishes of the World. }} ==Characteristics==