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Parasemionotiformes
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. Parasemionotiforms were normally small to medium-sized fishes. They were predominantly marine. Evolutionary relationships 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. 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). Parasemionotiformes belong to Holostei and are one of the earliest clades of the Halecomorphi (bowfin and its extinct rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halecomorphi
Halecomorphi is a taxon of Actinopterygii, ray-finned bony fish in the clade Neopterygii. The only extant Halecomorph species are the bowfin (''Amia calva'') and eyespot bowfin (''Amia ocellicauda''), but the group contains many extinct species in several family (biology), families (including Amiidae, Caturidae, Liodesmidae, Sinamiidae) in the order (biology), order Amiiformes, as well as the extinct orders Ionoscopiformes, Panxianichthyiformes, and Parasemionotiformes. The fossil record of halecomorphs goes back at least to the Early Triassic epoch (geology), epoch. The Halecomorphi exhibit a combination of plesiomorphy, ancestral features, such as most heavily mineralized fish scale, scales, but also by more derived or "modern" features, particularly in the structure of the skull (e.g. position and shape of preopercles). Unique derived traits (synapomorphies) of the Halecomorphi include: *Unique jaw articulation in which the Quadrate bone, quadrate and Symplectic bone, sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neopterygian
Neopterygii (from Greek νέος ''neos'' 'new' and πτέρυξ ''pteryx'' 'fin') is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year. The potentially oldest known neopterygian is the putative " semionotiform" '' Acentrophorus varians'' from the Middle Permian of Russia; however, one study incorporating morphological data from fossils and molecular data from nuclear and mitochondrial DNA, places this divergence date at least 284 mya (million years ago), during the Artinskian stage of the Early Permian. Another study suggests an even earlier split (360 myr ago, near the Devonian-Carboniferous boundary). Evolution and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
