| Diandongpetalichthys Temporal range: Lochkovian | |
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| Genus: | Diandongpetalichthys |
| Species: | D. liaojiaoshanensis |
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| Diandongpetalichthys liaojiaoshanensis P'an & Wang, 1978 | |
Diandongpetalichthys liaojiaoshanensis is an extinct petalichthyid placoderm from the Early Devonian of China.
Several specimens, in the forms of one complete and several incomplete skull roofs, disarticulated portions of the trunk shield, and spines, are known, found in the Devonian aged Liaojiaoshan Hill of Qujing, Yunnan, a non-marine portion of the Xishancun Formation, in the Cuifengshan Group. [1]
The holotype of D. liaojiaoshanensis is a poorly preserved, incomplete skull roof, and was, at the time of its description in 1978, regarded as "Petalichthyida incertae sedis . In light of more, better preserved specimens that show features in common with primitive arthrodires, such as actinolepids and the phlyctaeniids, D. liaojiaoshanensis is now regarded as a basal petalichthyid. [1] [2]
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.
Dunkleosteus is an extinct genus of large arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first apex predators of any ecosystem.
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.
Dinichthys is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian measuring around 3 metres (9.8 ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.
Minicrania is an extinct genus of tiny antiarch fish, with armor averaging up to about 2 centimetres (0.79 in) long, which lived during the Lochkovian epoch in Early Devonian Yunnan Province, China and northern Vietnam.
Gavinaspis is a phyllolepid placoderm which lived during the Early Devonian period, of Qujing, Yunnan province, south China.
Dicksonosteus is an extinct genus of basal arthrodire placoderm fish which lived during the Early Devonian period of Spitsbergen, Norway.
Quasipetalichthys haikouensis is the type and only known species of the extinct petalichthid placoderm, Quasipetalichthys. Fossil remains of Quasipetalichthys have been found in the Middle Devonian, Givetian faunal stage of China.
Aleosteus is an extinct monospecific genus of arthrodire placoderm fish of the Early Devonian period. The type species Aleosteus eganensis was described in 2000, and was found in the Late Emsian strate of the Sevy Dolomite Formation, in the Egan Range of east-central Nevada, USA. Almost complete fossils belong to juvenile and adult specimens and show a short and broad skull, posteriorly concave.
Rhachiosteus is an extinct monospecific genus of arthrodire placoderm from the Middle to Late Devonian of Germany. It is known only from a single specimen, which may be a larval or juvenile form, as the skull of said specimen is only 19 millimetres long.
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.
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.
Stenosteus is an extinct monospecific genus of medium-sized selenosteid arthrodire placoderms of the Late Devonian period known from the Upper Famennian Cleveland Shale of Ohio. Estimated skull lengths range from 6 to 9 centimeters Most fossils of Stenosteus have been scraps of armor and portions of tooth-plates suggestive of Selenosteus. In 1996, enough material of a new species, S. angustopectus, was recovered to allow a reconstruction of armor that resembles that of Selenosteus.
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.
Neopetalichthys yenmenpaensis is an extinct petalichthid placoderm from the Early Devonian of China.
Protitanichthys is an extinct genus of comparatively large coccosteid arthrodire placoderms from the Middle Devonian of the eastern United States. Fossils are found primarily in the Eifelian-epoch aged Delaware Limestone of Ohio, and the Lower Givetian-aged Rockport Quarry Limestone of Michigan
Edenopteron is a genus of large tristichopterid fish from the Late Devonian (Famennian) of what is now southeastern Australia. It is known from a single specimen of a single species, E. keithcrooki, described in 2013.
Yujiangolepis is an extinct monospecific genus of arthrodire placoderm fish from the Pragian stage of the Devonian period. The type species is Yujiangolepis liujingensis, described from a single incomplete skull roof from the Nakaoling (Nagaoling) Formation of Hengxian, Guangxi, South China. It is one of the more basal members of the order Arthrodira, closely related to Antarctaspis, as shown in the cladogram below:
Herasmius is an extinct genus of heterosteid placoderm from the Devonian period. Fossils have been discovered freshwater deposits in Norway and Canada.
Millerosteus is an extinct genus of coccosteid arthrodire placoderm from the Early Givetian stage of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. It was a small placoderm with an body length of 14 cm (5.5 in). Millerosteus is one of the few arthrodires known from specimens preserving the entire skeleton.
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