The Bear Gulch Limestone is a limestone-rich geological lens in central Montana, renowned for the quality of its late Mississippian-aged fossils. It is exposed over a number of outcrops northeast of the Big Snowy Mountains, and is often considered a component of the more widespread Heath Formation. The Bear Gulch Limestone reconstructs a diverse, though isolated, marine ecosystem which developed near the end of the Serpukhovian age. It is a lagerstätte, a particular type of rock unit with exceptional fossil preservation of both articulated skeletons and soft tissues. Bear Gulch fossils include a variety of fish, invertebrates, and algae occupying a number of different habitats within a preserved shallow bay.
Falcatus is an extinct genus of falcatid chondrichthyan which lived during the early Carboniferous Period in Bear Gulch bay in what is now Montana.
The Palaeonisciformes, commonly known as "palaeoniscoids" are an extinct grouping of primitive ray-finned fish (Actinopterygii), spanning from the Silurian/Devonian to the Cretaceous. They are generally considered paraphyletic, but their exact relationships to living ray-finned fish are uncertain. While some and perhaps most palaeoniscoids likely belong to the stem-group of Actinopteryii, it has been suggested that some may belong to the crown group, with some of these possibly related to Cladistia and/or Chondrostei. Many palaeoniscoids share a conservative body shape and a similar arrangement of skull bones.
Pteronisculus is an extinct genus of prehistoric ray-finned fish that lived during the Early Triassic and Middle Triassic epochs of the Triassic period worldwide.
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.
Cornuboniscus is an extinct genus of prehistoric freshwater ray-finned fish that lived during the Pennsylvanian epoch (Carboniferous), and the only member of the family Cornuboniscidae. It contains a single species, C. budensis from the Bashkirian/lower Westphalian age of what is now Cornwall, England. The genus Cornubonisus was named after the island of Cornubian, and the species name refers to the coastal town of Bude in Cornwall. The type specimen is held in the town's Castle Heritage Centre.
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.
Watsonichthys is an extinct genus of prehistoric bony fish that lived during the Tournaisian age to possibly the Asselian age in what is now Europe and possibly Namibia. It is named after David Meredith Seares Watson.
Scanilepis is an extinct genus of prehistoric bony fish that lived during the Rhaetian-?Hettangian ages. The type species, S. dubia, is known from the Rhaetian freshwater deposits of the Bjuv member of the Höganäs Formation, southwestern Sweden. A second species, S. spitzbergensis was mentioned from the Hettangian of the Festning section of the Grøfjorden area in Spitsbergen, Norway but was never described.
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.
Cosmolepis is an extinct genus of prehistoric marine ray-finned fish that lived during the Early Jurassic epoch. It contains a single species, C. ornatus from the Blue Lias in what is now England. It is the only member of the family Cosmolepididae.
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.
Rhadinichthys is an extinct genus of prehistoric bony fish. It is known from several species that lived in the Late Devonian epoch, the Carboniferous period and the Cisuralian epoch in what is now Europe, South Africa, and North and South America. Some isolated scales from the Cisuralian of Europe were also referred to this genus.
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.
Bourbonnella is an extinct genus of prehistoric freshwater and coastal marine ray-finned fish that lived during the late Mississippian (Carboniferous) and Asselian in what is now Burgundy, the Czech Republik, and Utah, with other remains known from elsewhere. The genus was named by Daniel Heyler in 1967.
Discoserra is a prehistoric ray-finned fish from the Mississippian of the Bear Gulch Limestone in Montana. It is a member of the Guildayichthyiformes with a round body and a skull possessing primitive and modern traits. Discoserra is about 60 mm long. In 2006, Discoserra was hypothesized to be a stem neopterygian, although it has alternatively been placed in Cladistia along with other Guildayichthyiformes.
Turseodus is an extinct genus of ray-finned fish found in Late Triassic freshwater sediments of the United States. Two species have been described, T. acutus from the Lockatong Formation of Pennsylvania, and T. dolorensis from the Chinle Formation of Colorado.
Pygopterus is an extinct genus of prehistoric bony fish that lived during the Wuchiapingian to Olenekian ages in what is now England, Germany, Greenland and Svalbard (Spitsbergen). It is one of the few genera of ray-finned fish known to cross the Permian-Triassic boundary.
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.
Bluefieldius is an extinct genus of prehistoric marine ray-finned fish that lived during the Late Mississippian epoch in what is now West Virginia, United States. It is known from a single fossil collected from the late Serpukhovian or early Viséan Bluefield Formation. The type and only species (monotypy) is Bluefieldius mercerensis.
