Hoplocarida is a subclass of crustaceans. The only extant members are the mantis shrimp (Stomatopoda), but two other orders existed in the Palaeozoic: Aeschronectida and Palaeostomatopoda.
Stethacanthus is an extinct genus of shark-like holocephalians which lived from the Late Devonian to Late Carboniferous epoch, dying out around 298.9 million years ago. Fossils have been found in Asia, Europe and North America.
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.
Belantsea is a genus of extinct petalodontid cartilaginous fish that lived during the Lower Carboniferous, about 350 million years ago. Its fossils are found in the Bear Gulch Limestone lagerstätte. Its body was leaf-shaped, with muscular fins and a small tail. Such a body plan would allow for great maneuverability, but at the cost of speedy cruising. Its few, large, triangular teeth formed a beak-like arrangement that allowed it to graze bryozoans, sponges, crinoids, and other encrusting animals. The genus contains two species, B. montana and B. occidentalis.
Symmoriiformes is an extinct order of holocephalians. Originally named Symmoriida by Zangerl (1981), it has subsequently been known by several other names. Lund (1986) synonymized the group with Cladodontida, while Maisey (2008) corrected the name to Symmoriiformes in order to prevent it from being mistaken for a family. The symmoriiform fossils record begins during the late Devonian. Most of them died out at the start of the Permian, but Dwykaselachus is known from the Artinskian-Kungurian of South Africa. Teeth described from the Valanginian of France and Austria indicate that members of the family Falcatidae might have survived until the Early Cretaceous; however, these teeth were also argued to be more likely neoselachian teeth.
Falcatus is an extinct genus of falcatid chondrichthyan which lived during the early Carboniferous Period in Bear Gulch bay in what is now Montana.
Stethacanthidae is an extinct family of prehistoric holocephalians. It is estimated to have existed approximately between 380 and 300 million years ago. Members of this family are noted for their peculiar dorsal fin.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2000.
Harpagofututor is an extinct genus of cartilaginous fish from the Mississippian of North America.
Netsepoye is an extinct genus of cartilaginous fish distantly related to the modern order Chimaeriformes, containing the single species Netspoye hawesi. It lived more than 320 million years ago during the Late Mississippian.
Siksika ottae is an extinct genus of petalodont, which lived during the Upper Mississippian. It has been discovered at the well known Carboniferous-aged Bear Gulch Limestone. It is known primarily from fossil teeth, but also from partial neurocranium and mandibles which hint at a close relationship to coeval petalodontiforms such as Janassa and Netsepoye. Dentition is generally heterodont. Siksika translates to Blackfoot, being named after the Siksika Nation.
Falcatidae is a family of Paleozoic holocephalians. Members of this family include Falcatus, a small fish from the Bear Gulch Limestone of Montana. The family first appeared around the start of the Carboniferous, and there is some evidence that they survived well into the early Cretaceous, though its putative Cretaceous members were also argued to be more likely neoselachians.
Echinochimaera is an extinct genus of chimaeriform fish, known from the Lower Carboniferous Bear Gulch Limestone in Montana, United States. It is one of the earliest Chimaeriformes known.
Aeschronectida is an extinct order of mantis shrimp-like crustaceans which lived in the Mississippian subperiod in what is now Montana. The first species of Aeschronectida is accredited to Frederick R. Schram. They diverge substantially from typical hoplocaridan morphology by having more unmodified thoracopods.
Sairocaris is an extinct genus of crustaceans, in the order Hoplostraca, that lived in the Mississippian age.
Guildayichthyidae is a prehistoric family of marine fish from the Mississippian Bear Gulch Limestone of Montana. It is the only family in the order Guildayichthyiformes. Guildayichthyids possess an uncommon mixture of primitive and modern characteristics in their skull bones.
Thrinacodus is an extinct genus of basal elasmobranch, found worldwide from the Late Devonian-Lower Carboniferous. Most species are only known from their tricuspid teeth. T. gracia, originally placed in the separate genus Thrinacoselache from the Serpukhovian-aged Bear Gulch Limestone, of what is now Montana, is known from full body impressions, showing a long, slender eel-like body up to a metre in length, with an elongate rostrum. Stomach contents of T. gracia include remains of crustaceans and small chondrichthyan fish. It is a member of the Phoebodontiformes.
Gregoriidae is an extinct family of early sharks from the Carboniferous period. It currently includes three described genera: Gregorius, Srianta, and Bealbonn. This family includes remains formerly ascribed to "Desmiodus," which is now considered a nomen vanum. The relationships between the included genera are not entirely clear. Fossils are known from Serpukhovian-aged formations including the Bear Gulch Limestone and Surprise Canyon Formation.
Squatinactis is a genus of extinct elasmobranch Chondrichthyes known from the Carboniferous aged Bear Gulch Limestone in Montana. This fish was discovered in 1974 by Richard Lund. The type specimen, named CMNH 46133, consists of a brain case, poorly preserved jaws and gills, a pectoral fin, and a partial vertebral axis. This creatures most startling feature were its broad pectoral fins which resembled those of stingrays and angel sharks (Squatina). The holotype specimen has about 15 teeth in its jaw. This creature is named after the angel shark. Teeth found in Derbyshire, England, have been tentatively identified as those belonging to S. caudispinatus.
Syllipsimopodi is an extinct member of the cephalopod subclass Coleoidea belonging to the clade Vampyropoda, which includes octopuses (Octopoda) and vampire squids (Vampyromorphida). The type and only known species is Syllipsimopodi bideni, named in honor of US President Joe Biden, and to raise awareness of his climate change policies. The well-preserved holotype fossil was found in the Bear Gulch Limestone deposit in the US state of Montana in 1988, and donated that year to the Royal Ontario Museum by one B. Hawes, designated ROMIP 64897. The species lived during the (Carboniferous) mississippian 330.3 to 323.4 million years ago pushing back the group of cephalopods by 81.9 million years. The cephalopod was named after Joe Biden, who was president of the United States at the time of its discovery. Whalen and Landman said in an interview that this name was chosen because they were, “encouraged by his plans to address climate change and to fund scientific research”.
