Permian extinctions

Acanthodii or acanthodians is an extinct class of gnathostomes (jawed fishes). They are currently considered to represent a paraphyletic grade of various fish lineages basal to extant Chondrichthyes, which includes living sharks, rays, and chimaeras. Acanthodians possess a mosaic of features shared with both osteichthyans (bony fish) and chondrichthyans (cartilaginous fish). In general body shape, they were similar to modern sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteians (gars, bowfins).

Eurypterids, often informally called sea scorpions, are a group of extinct marine arthropods that form the order Eurypterida. The earliest known eurypterids date to the Tremadocian stage of the Ordovician period, 480 million years ago. The group is likely to have appeared first during the Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described.

Helicoprion is an extinct genus of large shark-like cartilaginous fish that lived from the Early to the Middle Permian, about 290-270 million years ago. Helicoprion is a member of the Eugeneodontiformes, an extinct order of cartilaginous fish within the clade Holocephali, a group today represented only by chimaeras. It is also the type genus of the Helicoprionidae, a family of eugeneodonts characterised by distinctive tooth structures called tooth whorls. Helicoprion was first named in 1899 by Alexander Karpinsky on the basis of fossils discovered in Russia and Australia, the generic name mean

thumb|right|200px|"Blastoidea", from Ernst Haeckel's Art Forms of Nature, 1904

The Rostroconchia is a class of extinct molluscs dating from the early Cambrian to the Late Permian. They were initially thought to be bivalves, but were later given their own class. They have a single shell in their larval stage, and the adult typically has a single, pseudo-bivalved shell enclosing the mantle and muscular foot. The anterior part of the shell probably pointed downward and had a gap from which the foot could probably emerge. Rostroconchs probably lived a sedentary semi-infaunal lifestyle. There were probably more than 1,000 species of members of this class.

200px|thumb|left|Teeth of Petalodus|Petalodus ohioensis Petalodontiformes ("thin-plate teeth") is an extinct order of marine cartilaginous fish related to modern day chimaera found in what is now the United States of America and Europe.

Nectridea is an extinct order of lepospondyl tetrapods from the Carboniferous and Permian periods, including animals such as Diplocaulus. In appearance, they would have resembled modern newts or aquatic salamanders, although they are not close relatives of modern amphibians. They were characterized by long, flattened tails to aid in swimming, as well as numerous features of the vertebrae.

Glossopteridales is an extinct order of seed plants, known from the Permian of Gondwana. They arose at the beginning of the Permian, and the majority or all members of the group became extinct during the Permian–Triassic extinction event, 251.9 mya. Possible Triassic records of the group have been recorded. The best known genus is Glossopteris, a leaf form genus. Other examples are Gangamopteris, Glossotheca, and Vertebraria.

Embolomeri is an order of tetrapods or stem-tetrapods, possibly members of Reptiliomorpha. Embolomeres first evolved in the Early Carboniferous (Mississippian) Period and were the largest and most successful predatory tetrapods of the Late Carboniferous (Pennsylvanian) Period. They were specialized semiaquatic predators with long bodies for eel-like undulatory swimming. Embolomeres are characterized by their vertebral centra, which are formed by two cylindrical segments, the pleurocentrum at the rear and intercentrum at the front. These segments are equal in size. Most other tetrapods have ple

Eryopidae are an extinct family of medium to large sized amphibious temnospondyls that lived from the latest Carboniferous (Pennsylvanian) to the early Permian period and inhabited North America and Europe. They were apex predators in the stream and lake habitats they inhabited. Their life cycle (exemplified by Onchiodon) consist of a small larvae that grows into a heavily ossified adult. This group are unusual in their variability in their morphology and development.

Edrioasteroidea is an extinct class of echinoderms. The living animal would have resembled a pentamerously symmetrical disc or cushion. They were obligate encrusters and attached themselves to inorganic or biologic hard substrates (frequently hardgrounds or brachiopods). A 507 million years old species, Totiglobus spencensis, is actually the first known echinoderm adapted to live on a hard surface after the soft microbial mats that covered the seafloor were destroyed in the Cambrian substrate revolution.

Megasecoptera is a Paleozoic insect order. There are 22 known families of megasecopterans, with about 35 known genera.

Eryopoidea is a clade of late Carboniferous and Permian temnospondyl amphibians, known from North America and Europe. Carroll (1998) includes no fewer than ten families, but Yates and Warren (2000) replaced this with a cladistic approach that includes three closely related families, the Eryopidae, Parioxyidae and Zatrachydidae. They define the Eryopoidea as all members of Euskelia in which the choana are relatively rounded and the iliac blade is vertical. A similar definition (without specifically naming Euskelia) is provided by Laurin and Steyer (2000).

Acanthodiformes (alternatively spelled Acanthodida) is an order of "acanthodians" which lived from the Early Devonian to the Early Permian. Members of the order have been found worldwide in rocks preserving both freshwater and marine environments, and are distinguished from other acanthodians by the presence of only a single dorsal fin and dorsal fin spine, and in most members a lack of teeth and well-developed gill rakers. Some acanthodiforms are presumed to have fed by filter-feeding, and had large mouths and gill arches. While they have been suggested to be close relatives of modern bony fi

Archegosauroidea is an extinct superfamily of Permian temnospondyls. The superfamily is assigned to the clade Stereospondylomorpha and is the sister taxon to the suborder Stereospondyli. It includes the families Actinodontidae and Archegosauridae, and possibly the genus Intasuchus, which is placed within the monotypic family Intasuchidae. They were fully aquatic animals, and were metabolically and physiologically more similar to fish than modern amphibians.

Walchia is a primitive fossil conifer found in upper Pennsylvanian (Carboniferous) and lower Permian (about 310-290 Mya) rocks of Europe and North America. A forest of in-situ Walchia tree-stumps is located on the Northumberland Strait coast at Brule, Nova Scotia.

Adelophthalmoidea (the name deriving from the type genus Adelophthalmus, meaning "no obvious eyes") is a superfamily of eurypterids, an extinct group of aquatic arthropods. Adelophthalmoidea is classified within the infraorder Diploperculata, in the suborder Eurypterina. The superfamily contains four families: Adelophthalmidae, Nanahughmilleriidae, Parahughmilleriidae, and Pittsfordipteridae.''''''

Mycteroptidae or Mycteropidae are a family of eurypterids, a group of extinct chelicerate arthropods commonly known as "sea scorpions". The family is one of three families contained in the superfamily Mycteropoidea (along with Hibbertopteridae and Drepanopteridae), which in turn is one of four superfamilies classified as part of the suborder Stylonurina.

The order Pygocephalomorpha is an extinct group of peracarid crustaceans. Pygocephalomorpha appeared in the Late Devonian, were abundant from the Carboniferous era until their extinction in the Early Permian era.

Stylonurina is one of two suborders of eurypterids, a group of extinct arthropods commonly known as "sea scorpions". Members of the suborder are collectively and informally known as "stylonurine eurypterids" or "stylonurines". They are known from deposits primarily in Europe and North America, but also in Siberia.

Whaitsiidae is an extinct family of therocephalian therapsids. Whaitsiids were among the most diverse therocephalians of the Late Permian, though they would go extinct at the end-Permian mass extinction.

Cheirophyllum is an extinct plant genus that existed during the Permian.

Pylaecephalidae is a family of dicynodont therapsids that includes Diictodon, Robertia, and Prosictodon from the Permian of South Africa. Pylaecephalids were small burrowing dicynodonts with long tusks. The family was first named in 1934 and was redefined in 2009. Diictodontidae and Robertiidae are considered junior synonyms of Pylaecephalidae; although Pylaecephalus itself is considered a junior synonym of Diictodon, the name Pylaecephalidae predates these names and therefore takes priority.

Mycteropoidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Mycteropoids have been recovered from Europe, Russia, South America and South Africa. Mycteropoid specimens are often fragmentary, making it difficult to establish relationships between the included taxa. Only two mycteropoid taxa are known from reasonable complete remains, Hibbertopterus scouleri and H. wittebergensis.

Callistophytales is an extinct order of spermatophytes (seed plants) which lived from the Pennsylvanian (Late Carboniferous) to Permian periods. They were mainly scrambling and lianescent (vine-like) plants found in the wetland "coal swamps" of Euramerica and Cathaysia. Like many other early spermatophytes, they could be described as "seed ferns", combining ovule-based reproduction with pinnate leaves superficially similar to modern ferns.

Hofmeyriidae is a family of therocephalian therapsids. It includes the genus Ictidostoma and others.

Eurypterina is one of two suborders of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". Eurypterine eurypterids are sometimes informally known as "swimming eurypterids". They are known from fossil deposits worldwide, though primarily in North America and Europe.

The Medullosales is an extinct order of pteridospermous seed plants characterised by large ovules with circular cross-section and a vascularised nucellus, complex pollen-organs, stems and rachides with a dissected stele, and frond-like leaves. Their nearest still-living relatives are the cycads.

Cystoporida, also known as Cystoporata or cystoporates, are an extinct order of Paleozoic bryozoans in the class Stenolaemata. Their fossils are found from Ordovician to Triassic strata.

Rubidgeinae is an extinct subfamily of gorgonopsid therapsids known only from Africa. They were among the largest gorgonopsians, and their fossils are common in the Cistecephalus and Daptocephalus assemblage zones of the Karoo Basin. They lived during the Late Permian, and became extinct at the end of the Permian.

Hibbertopteridae (the name deriving from the type genus Hibbertopterus, meaning "Hibbert's wing") is a family of eurypterids, an extinct group of aquatic arthropods. They were members of the superfamily Mycteropoidea. Hibbertopterids were large, broad and heavy animals unlike virtually every other group of eurypterids, which are commonly streamlined and lightweight. Their bizarre morphology is so unusual that they in the past have been thought to represent an entirely distinct order of chelicerates. Fossils of the family first appear in deposits of Middle Devonian age and the last known fossil

Petalodontidae is an extinct family of marine cartilaginous fish related to the modern-day chimaeras, found in what is now the United States of America and Europe. With a very few exceptions, they are known entirely from teeth. All fossils range from the Carboniferous to the Permian, where they are presumed to have died out during the Permian/Triassic extinction event.

Phlegethontiidae is a family of extinct aistopod tetrapodomorphs including the genera Phlegethontia and Sillerpeton.

Orthoceratidae, from Ancient Greek ὀρθός (orthós), meaning "straight", and κέρας (kéras), meaning "horn", is an extinct family of actively mobile carnivorous cephalopods, subclass Nautiloidea, that lived in what would be North America, Europe, Asia, Africa, and Australia from the Ordovician through Triassic from 490—203.7 mya, existing for approximately .