The beardfishes consist of a single extant genus, Polymixia, of deep-sea marine ray-finned fish named for their pair of long hyoid barbels. They are classified in their own order Polymixiiformes. But as Nelson says, "few groups have been shifted back and forth as frequently as this one, and they were recently added to Paracanthoptergii". For instance, they have previously been classified as belonging to the Beryciformes, and are presently considered either paracanthopterygians or the sister group to acanthopterygians. They are of little economic importance.
Cimolichthys is an extinct genus of large predatory marine aulopiform ray-finned fish known worldwide from the Late Cretaceous. It is the only member of the family Cimolichthyidae.
Acanthomorpha is an extraordinarily diverse taxon of teleost fishes with spiny fin rays. The clade contains about one-third of the world's modern species of vertebrates: over 14,000 species.
Belonostomus is a genus of prehistoric ray-finned fish that was described by Louis Agassiz in 1844. It is a member of the order Aspidorhynchiformes, a group of fish known for their distinctive elongated rostrums.
Dercetis is a genus of prehistoric marine ray-finned fish. It is the type genus of the family Dercetidae, a group of slender, elongate aulopiforms, which were related to modern lizardfish and grinners. It is known from the Late Cretaceous of Europe, the Middle East, and western North America.
Acrogaster is a genus of fossil marine fish in the order Trachichthyiformes, known from the Late Cretaceous period. Species are known from Germany and Lebanon.
Cladocyclus is an extinct genus of marine ichthyodectiform fish from the middle Cretaceous. It was a predatory fish of about 1.20 metres (3.9 ft) in length.
Dinopteryx is an extinct genus of prehistoric beardfish from the Late Cretaceous period. It contains a single species, D. spinosus, known from the Santonian of Lebanon. It is the only member of the extinct family Dinopterygidae, which is considered a distinct family of the Polymixiiformes. It was previously placed in the genus Hoplopteryx.
Dactylopogon is an extinct genus of prehistoric marine ray-finned fish that lived during the Late Cretaceous. It contains a single species, D. grandis from the Campanian of the Ahlen Formation of Germany. It was previously considered a myctophiform, but more recent studies have found it to be an elopomorph. A second species, D. parvulus from the Cenomanian-aged Sannine Formation in Lebanon has also sometimes been placed in this genus.
Telepholis is an extinct genus of prehistoric bony fish that lived from the Cenomanian to Campanian.
Cryptoberyx is an extinct genus of prehistoric marine ray-finned fish that lived during the late Cenomanian stage of the Late Cretaceous. Two species are known from southern Europe and the Middle East, both part of the former Tethys Sea.
Anomoeodus is an extinct genus of prehistoric marine ray-finned fish belonging to the family Pycnodontidae. This genus primarily lived during the mid-to-late Cretaceous period, ranging from the Albian to the very end of the Maastrichtian age, and possibly into the Danian. The first fossils of Anomoeodus were described by Louis Agassiz in 1833, although they were described under Pycnodus. Some studies have recovered it as a wastebasket taxon.
Ctenothrissa is a prehistoric genus of marine ray-finned fish in the order Ctenothrissiformes. It contains a number of species known from the Late Cretaceous of England and Lebanon.
Dalmatichthys is an extinct genus of marine beardfish from the Late Cretaceous. It contains a single species, D. malezi from Croatia. It is the only member of the family Dalmatichthyidae, which is sometimes considered synonymous with Polymixiidae. Its exact relationship to modern beardfish in Polymixia likely needs further research.
The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic formation in Lebanon. It is a Konservat-Lagerstätte that contains a high diversity of well-preserved fish, reptiles, and invertebrates from the Tethys Ocean within its three main localities: Haqel, Hjoula, and Nammoura.
Cheirothricidae is a family of extinct marine ray-finned fish, perhaps belonging to the Aulopiformes, although they are tentatively placed as indeterminate eurypterygians. They lived during the Upper Cretaceous and their fossil remains are found in the Middle East and Europe. They were characterized by very expanded even fins.
Tselfatiiformes is an extinct order of bony fishes from the infraclass Teleostei. The order represents the most important radiation of marine teleosts during the Cretaceous period. Fossils of tselfatiiforms are known from Europe, North America, central and northern South America, the Middle East and North Africa.
Agassizilia is an extinct genus of both freshwater and marine pycnodont fishes from the mid-late Cretaceous. The genus is named after paleontologist Louis Agassiz.
The Dercetidae are an extinct family of aulopiform ray-finned fish that are known from the Late Cretaceous to the early Paleocene. They are among the many members of the diverse, extinct suborder Enchodontoidei, which were dominant during the Cretaceous.
The Akrabou Formation is a Late Cretaceous -aged geological formation and Konservat-Lagerstätte in Morocco. It overlies the slightly older freshwater deposits of the Kem Kem Group, which it was once thought to be apart of. It was deposited over following the Kem Kem ecosystem's submergence by the Tethys Ocean during a marine transgression from the Cenomanian-Turonian boundary event, as part of a wider deposition of carbonate platforms across the region from the event.
