Halecostomi

Halecostomi is the name of a group of neopterygian fish uniting the halecomorphs (represented by the living bowfin and many extinct groups) and the teleosts, the largest group of extant ray-finned fish.^[1]

Outdated phylogenetic hypothesis of Actinopterygii proposing a sister group relationship between Amiiformes (Halecomorphi) and Teleostei

Halecostomi
Amia calva (bowfin)
Hiodon tergisus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Subclass:	Neopterygii
(unranked):	Halecostomi Regan, 1903
Subdivisions
Halecomorphi Teleostei

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The Halecostomi hypothesis and the Holostei hypothesis are two competing hypotheses explaining the evolutionary relationships of living ray-finned fish. The Holostei hypothesis is better supported, rendering the Halecostomi a paraphyletic group (i.e., rejecting the Halecostomi hypothesis).^[2][3][4][5]

The Holostei hypothesis posits that Ginglymodi (gars and their fossil relatives) and Halecomorphi form a clade, called Holostei, and that the Holostei are the sister group to the Teleostei.

Neopterygii	Holostei Ginglymodi (gars and their fossil relatives) Halecomorphi (bowfin and its fossil relatives) Teleostei