Parasemionotiformes Temporal range:
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Albertonia cupidinia fossil | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Infraclass: | Holostei |
Order: | †Parasemionotiformes Lehman, 1966 |
Families | |
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Parasemionotiformes is an extinct order of neopterygian ray-finned fish that existed globally during the Triassic period. It comprises the families Parasemionotidae and Promecosominidae. Many of the included genera are monotypic and most species lived during the Early Triassic epoch.[1][2]
Parasemionotiforms were normally small to medium-sized fishes. They were predominantly marine.[3]
Parasemionotiformes are neopterygians, which is the clade that encompasses the vast majority of living ray-finned fishes (Actinopterygii) and about half of all living species of vertebrates.[4] Neopterygii are divided into Teleostei and Holostei. The latter represents a depauperate group today but used to be a diverse clade especially during the Mesozoic Era. The only surviving members of the Holostei are the gars (Ginglymodi) and the bowfin (Halecomorphi).[4]
Parasemionotiformes belong to Holostei and are one of the earliest clades of the Halecomorphi (bowfin and its extinct relatives).[5] Parasemionotiformes are the sister group to all other halecomorphs according to cladistic analyses.[6]
The following tree summarizes the evolutionary relationships of the Parasemionotiformes. Names accompanied by a dagger (†) represent extinct groups.
Neopterygii |
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