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| Genus: | Dialipina |
Dialipina is an extinct genus of prehistoric, marine osteichthyan. [2] It was initially thought to be an early, basal actinopterygian, but recent phylogenetic analyses suggest that it may instead be a stem-osteichthyan. [3] [4]
Acanthodii or acanthodians is an extinct class of gnathostomes. 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 and chondrichthyans. In general body shape, they were similar to modern sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteians.
Arthrodira is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. Arthrodires were the largest and most diverse of all groups of placoderms.
Meemannia is a genus of extinct bony fish from the early Devonian period. It was initially classified as a lobe-finned fish; however, a restudy conducted by Lu et al. (2016) indicates that it was actually an early-diverging ray-finned fish. It was found in Yunnan, China. As preserved, it consists mainly of skull roofing bones and a partial otic region of the braincase. Its anatomy is unique in a number of features that resemble ray-finned fishes (Actinopterygii), and more generalized jawed vertebrates.
Styloichthys is a prehistoric sarcopterygian, lobe-finned fish which lived during the Early Devonian (Lochkovian) period of East Yunnan, South China.
Luckeus is an extinct genus of prehistoric lobe-finned fish. Luckeus belonged to the order Onychodontida. It lived during the Early Devonian to Middle Devonian period in what os now central Australia.
Birgeria is a genus of carnivorous marine ray-finned fish from the Triassic period. Birgeria had a global distribution. Fossils were found in Madagascar, Spitsbergen, Germany, Switzerland, Italy, Slovenia, China, Russia, Canada and Nevada, United States. The oldest fossils are from Griesbachian aged beds of the Wordie Creek Formation of East Greenland.
Andreolepis is an extinct genus of prehistoric fish, which lived around 420 million years ago. It was described by Walter Gross in 1968 based on scales found in the Hemse Formation in Gotland, Sweden. It is placed in the monogeneric family Andreolepididae and is generally regarded as a primitive member of the class Actinopterygii based on its ganoid scale structure; however some new research regards it as a stem group of osteichthyans.
Osteolepididae is a family of primitive, fish-like tetrapodomorphs that lived during the Devonian period. The family is generally thought to be paraphyletic, with the traits that characterise the family being widely distributed among basal tetrapodomorphs and other osteichthyans. Some of genera historically placed in Osteolepididae have more recently been assigned to the family Megalichthyidae, which appears to be a monophyletic group.
Amadeodipterus is an extinct genus of lungfish which lived during the Devonian period. Fossils have been found in Central Australia.
Achoania is an extinct genus of primitive bony fish which lived during the Early Devonian period. It is known from a skull discovered in the Xitun Formation of Yunnan, China. While originally originally considered to be a lobe-finned fish, later studies suggested that it may be a stem-group Osteichthyes instead.
Guiyu oneiros is one of the earliest articulated bony fish discovered. Fossils of Guiyu have been found in what is now Qujing, Yunnan, China, in late Silurian marine strata, about 425 million years old.
Muranjilepis is an extinct genus of prehistoric sarcopterygians or lobe-finned fish.
Porolepis is an extinct genus of porolepiform sarcopterygian fish, from the Early Devonian Dniester Series of Ukraine, which is rich in Porolepis remains, and also the Nellen Koepfchen Beds of Germany. It lived alongside the dubious lophotrochozoan Macrodontophion. It was first described in 1858 but Porolepis was not named as a sufficient species until 1891.
Acentrophorus is an extinct genus of prehistoric ray-finned fish from the Wuchiapingian of England and Germany (Kupferschiefer). There may also be a Triassic occurrence in Australia.
Stegotrachelus is an extinct genus of prehistoric bony fish that lived during the Middle Devonian epoch in what is now Shetland, Scotland.
Holopterygius is an extinct genus of prehistoric eel-like coelacanth known from the Devonian (Givetian–Frasnian) of Germany. Despite its specialized morphology and superficial dissimilarity to the usual Paleozoic coelacanth body plan, it is one of the most basal actinistian fish.
Ligulalepis is an extinct genus of prehistoric bony fish. Ligulalepis was first described from isolated scales found in the Taemas-Wee jasper limestones of New South Wales by Dr Hans-Peter Schultze (1968) and further material described by Burrow (1994). A nearly complete skull found in the same general location was described in Nature by Basden et al. (2000) claiming the genus was closely related to basal ray-finned fishes (Actinopterygii). In 2015 Flinders University student Benedict King found a more complete new skull of this genus which was formally described by Clement et al. (2018), showing the fish to be on the stem of all osteichthyans.
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish, and this group may have split early on from other agnathans.
Janusiscus schultzei is an extinct gnathostome vertebrate dating from the Early Devonian period in Siberia, approximately 415 million years ago. It may be the sister group of the last common ancestor of Chondrichthyes or Osteichthyes. This makes J. schultzei a sister species to all living jawed vertebrates. The species name is in honor of Hans-Peter Schultze; the genus named after Janus, the Roman god of duality.
Sam Giles is a palaeobiologist at the University of Birmingham. Her research combines modern imaging with fossils to understand the evolution of life, in particular that of early fish, and in 2015 "rewrote" the vertebrate family tree. She was a 2017 L'Oréal-UNESCO Rising Star and won the 2019 Geological Society of London Lyell Fund.
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