Pachycormus is an extinct genus of pachycormiform ray-finned fish known from the Early Jurassic of Europe. The type species P. macropterus was first named as a species of Elops by Henri Marie Ducrotay de Blainville in 1818, it was placed into the newly named genus Pachycormus by Louis Agassiz in 1833. Fossils have been found in marine deposits from France, Germany and England. Pachycormus has recently been considered monotypic, only containing P.macropterus, with other species considered junior synonyms of the former, though this has subsequently been questioned. Pachycormus has generally been considered basal among Pachycormiformes, with a recent phylogeny finding it to be the second most basal pachycormiform after Euthynotus. It grew up to 1 m (3.5 ft) in length. The teeth are short and designed for grasping. Its ecology has been interpreted as that of a generalist predator. Stomach contents indicate that its diet included cephalopods, and small fish, including juvenile Pachycormus. One particular specimen shows that it died because of swallowing an ammonite too large for its size, and the ammonite itself was only shortly digested just before the fish's death.
Casierius is an extinct genus of marine ray-finned fish that lived during the Albian stage of the Early Cretaceous epoch. It was a relative of the modern bonefish in the extinct family Phyllodontidae, although some authorities consider it either a true albulid or a very early eel. It contains a single species, C. heckeli, known from the Glen Rose Formation near Hood County, Texas.
Daedalichthys is an extinct genus of prehistoric freshwater ray-finned fish that lived during the Early Triassic epoch. It contains a single species, D. formosa from the Olenekian-aged Cynognathus Assemblage Zone of South Africa. It was previously classified in Dictyopyge.
Acrolepis is an extinct genus of prehistoric marine bony fish that lived from the Famennian stage of the Devonian to the early Triassic epoch. Some species from the Early Triassic of Tasmania are also ascribed to Acrolepis.
Styracopterus is an extinct genus of prehistoric bony fish that lived during the Tournaisian stage of the Mississippian epoch of Scotland and Eastern European Platform, Russia.
Cheirodopsis is an extinct genus of prehistoric marine ray-finned fish that lived during the Viséan stage of the Mississippian epoch. It contains a single species, C. geikiei from what is now Glencartholm, Scotland.
Cosmoptychius is an extinct genus of freshwater and estuarine ray-finned fish that lived during the Mississippian epoch. It contains a single species, C. striatus from the Visean of Scotland. It has a wide stratigraphic range in the Wardie Shale, with many specimens known.
Euthynotus is an extinct genus of prehistoric bony fish that lived during the early Toarcian stage of the Early Jurassic epoch. It is generally considered the basalmost pachycormiform.
Daitingichthys is an extinct genus of prehistoric marine ray-finned fish that lived during the Late Jurassic period. It contains a single species, D. tischlingeri from the early Tithonian-aged Mörnsheim Formation of the Solnhofen Limestone, Germany. It is thought to be a stem-elopiform, related to modern ladyfish and tarpons.
Bendenius is an extinct genus of prehistoric marine ray-finned fish. It is known from the Early Carboniferous of Belgium. It was named after Belgian paleontologist Pierre-Joseph van Beneden.
Cyranorhis is an extinct genus of prehistoric marine ray-finned fish that lived during the Serpukhovian age of the Carboniferous period. One species is known, C. bergeraci in the Bear Gulch Limestone what is now Montana, United States. It is named after French novelist Cyrano de Bergerac.
Cycloptychius is an extinct genus of prehistoric freshwater & marine ray-finned fish that existed throughout much of the Carboniferous period in Eurasia, and possibly into the Early Permian in South Africa. It was a member of the Rhadinichthyidae, a family of basal ray-finned fish that was formerly placed in the now-paraphyletic order Palaeonisciformes.
Dialipina is an extinct genus of prehistoric marine bony fish from the Early Devonian. It contains two species, both known from the high Arctic of Asia and North America. It was initially thought to be and sometimes still is treated as an early, basal actinopterygian, but recent phylogenetic analyses suggest that it may instead be a stem-osteichthyan.
Decazella is an extinct genus of prehistoric freshwater ray-finned fish that lived during the late Carboniferous period. It contains a single species, D. vetteri from the Gzhelian (Stephanian) age of what is now Occitania, France.
Strepheoschema is an extinct genus of prehistoric bony fish that lived during the early Mississippian (Tournaisian–Visean) in what is now Berwickshire, Scotland, and Northumberland, England. Fossils were recovered from the Ballagan Formation.
Prohalecites is an extinct genus of ray-finned fish from the Ladinian and possibly Carnian (Triassic) of Italy. It is the oldest known teleosteomorph, a group that includes extant teleosts and their close fossil relatives.
Igornella is an extinct genus of prehistoric bony fish that lived during the Gzhelian (Stephanian) to Asselian ages in what is now France (Burgundy).
Phanerosteon is an extinct genus of prehistoric bony fish from the Carboniferous period. The type species, P. mirabile, was recovered from the Calciferous sandstone series (Pennsylvanian), Scotland. A second species, P. phonax was described from the Serpukhovian aged Bear Gulch Limestone lagerstätte in Montana, United States.
Cavenderichthys is an extinct genus of prehistoric freshwater ray-finned fish from the Late Jurassic. It contains a single species, C. talbragarensis from the Talbragar Fish beds of New South Wales, Australia.
Coccocephalus is an extinct genus of prehistoric freshwater and marine basal ray-finned fish from the Carboniferous to the early Permian period. The type species, C. wildi, lived during the Bashkirian age of the Pennsylvanian epoch in what is now Lancashire, United Kingdom. One specimen of C. wildi is notable for having the earliest known instance of fossilized brain tissue in a vertebrate.
