Sarcopterygii —sometimes considered synonymous with Crossopterygii —is a taxon of the bony fishes whose members are known as lobe-finned fishes. The group Tetrapoda, a superclass including amphibians, reptiles, and mammals, evolved from certain sarcopterygians; under a cladistic view, tetrapods are themselves considered a group within Sarcopterygii.
Placodermi is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches.
Mizia is a genus of primitive antiarch placoderm found in Emsian-aged marine strata of Early Devonian China.
Dunkleosteus is an extinct genus of large armored, jawed fishes that existed during the Late Devonian period, about 382–358 million years ago. It consists of ten species, some of which are among the largest placoderms to have ever lived: D. terrelli, D. belgicus, D. denisoni, D. marsaisi, D. magnificus, D. missouriensis, D. newberryi, D. amblyodoratus, and D. raveri. The largest and most well known species is D. terrelli, which grew up to 8.79 m (28.8 ft) long and 4 t in weight. Dunkleosteus could quickly open and close its jaw, like modern-day suction feeders, and had a bite force of 6,000 N at the tip and 7,400 N at the blade edge. Numerous fossils of the various species have been found in North America, Poland, Belgium, and Morocco.
Coccosteus is an extinct genus of arthrodire placoderm from the Devonian period. Its fossils have been found throughout Europe and North America. The majority of these have been found in freshwater sediments, though such a large range suggests that they may have been able to enter saltwater. The largest specimens were about 40 centimetres (16 in), although the average length was 20 to 24 centimetres.
Petalichthyida is an extinct order of small, flattened placoderm fish. They are typified by their splayed pectoral fins, exaggerated lateral spines, flattened bodies, and numerous tubercles that decorated all of the plates and scales of their armor. They reached a peak in diversity during the Early Devonian and were found throughout the world, particularly in Europe, North America, Asia, South America, and Australia. The petalichthids Lunaspis and Wijdeaspis are among the best known. The earliest and most primitive known petalichthyid is Diandongpetalichthys, which is from earliest Devonian-aged strata of Yunnan. The presence of Diandongpetalichthys, along with other primitive petalichthyids including Neopetalichthys and Quasipetalichthys, and more advanced petalichthyids, suggest that the order may have arisen in China, possibly during the late Silurian.
Heintzichthys is an extinct monospecific genus of arthrodire placoderm that lived what is now Europe and North America during the Famennian stage of the Late Devonian period. The type specimen was discovered in the Cleveland Shale near Cleveland, Ohio, in the United States.
Eastmanosteus is a fossil genus of dunkleosteid placoderms. It was closely related to the giant Dunkleosteus, but differed from that genus in size, in possessing a distinctive tuberculated bone ornament, a differently shaped nuchal plate and a more zig-zagging course of the sutures of the skull roof.
Incisoscutum is an extinct genus of arthrodire placoderm from the Early Frasnian Gogo Reef, from Late Devonian Australia. The genus contains two species I. ritchiei, named after Dr. Alex Ritchie, a palaeoichthyologist and senior fellow of the Australian Museum, and I. sarahae, named after Sarah Long, daughter of its discoverer and describer, Dr. John A. Long.
Guiyu oneiros is the earliest articulated bony fish discovered. The generic name Guiyu is a transliteration of the Mandarin 鬼魚 guǐyú "ghost fish" and the specific name oneiros is from Greek ὄνειρος "dream". Fossils of Guiyu have been found in what is now Qujing, Yunnan, China, in a late Silurian marine strata, about 425 million years old. Guiyu remains have been found articulated, missing only the caudal fin. The living fish is estimated to have been aroun 30 cm long.
Mcnamaraspis is an extinct monospecific genus of arthrodire placoderm that inhabited the ancient reef system of north Western Australia during the Frasnian epoch of the Late Devonian period. The type specimen was found and described by John A. Long from the Gogo Formation near Fitzroy Crossing. This fossil fish showed new anatomical features in arthrodires, like the well-preserved annular (ring-shaped) cartilages of the snout, previously inferred to be present by Erik Stensiö of Sweden. It is occasionally referred to as "The Gogo Fish" after the locale the holotype was excavated from.
Gymnotrachelus is an extinct monospecific genus of large selenosteid arthrodire placoderm of the Late Devonian known from the Late Famennian Cleveland Shale of Ohio. The type species Gymnotrachelus hydei was originally reconstructed as physically resembling Selenosteus, with slightly smaller orbits. Later specimens led to a reappraisal, and now G. hydei is thought to have a more gar-like or barracuda-like build.
Rhinosteus is an extinct genus of small to medium selenosteid arthrodire placoderms of the Late Devonian known from the Upper Frasnian Kellwasserkalk facies of Bad Wildungen, Germany and Morocco.
Xiangshuiosteus wui is an extinct monospecific genus of brachythoracid arthrodire placoderm from the Late Emsian stage of the Early Devonian epoch, discovered in Wuding County of Yunnan province, China. It has recently been reassessed as a dunkleosteid.
Neopetalichthys yenmenpaensis is an extinct petalichthid placoderm from the Early Devonian of China.
Diandongpetalichthys liaojiaoshanensis is an extinct petalichthid placoderm from the Early Devonian of China.
Phymosteus liui is an extinct large selenosteid arthrodire placoderm known from the Lower Famennian Xiejingshi Formation of Shimen County, Hunan province, in central China.
Hongyu, represented by its type species Hongyu chowi, is an extinct Devonian lobe-finned fish. About 1.5 m in length, it resembles both Elpistostegalia and Rhizodontida, making its phylogenetic placement uncertain. The type specimen was discovered in the Zhongning Formation near Ningxia in China’s North China Block.
Yinostius is an extinct genus of heterosteid placoderm of the Middle Devonian known from remains discovered in China.
Compagopiscis is an extinct genus of placoderm known from the Gogo Formation. It lived in the Upper Devonian of Western Australia. Compagopiscis is one of the earliest known vertebrates to have teeth. The genus is monotypic, with its only species being Compagopiscis croucheri.
