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Buchanosteoidea
Buchanosteidae is a family of arthrodire placoderms that lived from the Early to Middle Devonian.White, E. I. (1952). Australian arthrodires. ''Bulletin of the British Museum (Natural History) (Geology)'' 1: 249–304. Fossils appear in various strata in Russia, Central Asia, Australia, and China. All buchanosteids tend to have flattened (of varying degrees depending on the genus) heads, with most genera also having large orbits. Genera ''Arenipiscis'' From the Emsian of New South Wales, it is known from several scrappy remains. It had a narrow skull, and the dermal surfaces of the bony armor were covered in a pattern of fine, granular tubercles. ''Buchanosteus'' The type genus, species are found in Emsian-aged strata in Australia, China, and Kazakhstan. ''Errolosteus'' One of several Taemas-Weejasper buchanosteid genera, ''Errolosteus'' had a comparatively broad, short skull. ''Exutaspis'' A "giant" buchanosteid from Emsian-aged strata in China. The holotype, an endocran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buchanosteus
''Buchanosteus'' is an extinct genus of arthrodire placoderm. Its fossils have been found in Early Devonian-aged marine strata throughout Asia and Australia. It contains the following species: *''B. confertituberculatus'', the type species, is known from several specimens found from the Emsian-aged Taemas-Weejasper Reef in what is now New South Wales, Australia. It coexisted sympatrically with other buchanosteid genera there. *''B. guangxianensis'' is known primarily from a well-preserved, albeit incomplete endocranium from Pragian-aged deposits near Guangxi, China. It is compared to another buchanosteid, the "giant" '' Exutaspis'' from the late Emsian Wuding Formation in Yunnan. *''B. nuricus'' is known from one or two specimens from Emsian strata in the Qaranghandy Region in Kazakhstan, and named for the Nura River The Nura ( kk, Нұра, ''Nura''; russian: Нура) is a major watercourse of northeast-central Kazakhstan. It is long and drains an area of . Course The riv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taemasosteus
''Taemasosteus'' is an extinct genus of arthrodire placoderm. Its fossils have been found in Emsian-aged marine strata in New South Wales, Australia. It contains two species, ''T. novaustrocambricus'', and ''T. maclartiensis''. The genus (and a monotypic family, "Taemasosteidae") was originally erected on the basis of "an imperfect" paranuchal, though, more specimens were found, eventually leading "Taemasosteidae" to be subsumed into Buchanosteidae. Even so, the reconstructed anatomy leads some researchers to conclude that ''Taemasosteus'' is close to the ancestry of Homostiidae. These researchers place ''Taemasosteus'' as the sister taxon of Homostiidae (or a select group of the better known homostiid genera) within the taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coccosteidae
Coccosteidae is a family of arthrodire placoderms from the Early to Late Devonian. Fossils appear in various strata in Europe, North America and China. Phylogeny Coccosteidae belongs to the larger clade Coccosteomorphi, which together with its sister clade Pachyosteomorphi forms the group Eubrachythoraci. The phylogeny of Coccosteidae can be shown in the cladogram below: Genera '' Belgiosteus'' A genus of very large coccosteids. Species are found in Middle Devonian Belgium and China. '' Clarkosteus'' ''Coccosteus'' The type genus of the family. Numerous species are found in Middle to Upper Devonian strata throughout Europe and parts of North America. ''Dickosteus'' ''Jiuchengia'' The earliest known coccosteid from Late Emsian Yunnan province, China. It is distinguished from other coccosteids by having an elongated occipital. '' Livosteus'' A genus of very large coccosteids known from Middle to Late Devonian strata of Eastern Europe. ''Millerosteus'' A genus of very smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phlyctaeniidae
Phlyctaeniidae is an extinct family of placoderm fishes that lived during the Devonian period, mainly in Norway and North America. Phylogeny ORDER ARTHRODIRA * Infraorder Actinolepina ** Family Actinolepidae * Suborder Phlyctaenioidei ** Family Holonematidae ** Infraorder Phlyctaeniina *** Family Groenlandaspididae ''Groenlandaspis'' is an extinct genus of arthrodire from the Late Devonian. Fossils of the different species are found in late Devonian strata in all continents except eastern Asia. The generic name commemorates the fact that the first specimen ... *** Family Phlyctaeniidae References Placoderm families {{Placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthrodire
Arthrodira (Greek for "jointed neck") is an Order (biology), 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. Description Arthrodire placoderms are notable for the movable joint between armor surrounding their heads and bodies. Like all placoderms, they lacked distinct teeth; instead, they used the sharpened edges of a bony plate on their jawbone as a biting surface. The eye sockets are protected by a bony ring, a feature shared by birds and some ichthyosaurs. Early arthrodires, such as the genus ''Arctolepis'', were well-armoured fishes with flattened bodies. The largest member of this group, ''Dunkleosteus'', was a true superpredator of the latest Devonian period, reaching as much as 6 m in length. In contrast, the long-nosed ''Rolfosteus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burrinjucosteus
''Burrinjucosteus asymmetricus'' is an extinct buchanosteid arthrodire placoderm. Its fossils have been found in Emsian-aged marine strata of New South Wales, Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma .... ''B. asymmetricus'' is known from scraps of thoracic armor and the skullroof, which suggest a very large, flat animal. References Buchanosteidae Prehistoric fish of Australia {{Placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goodradigbeeon
''Goodradigbeeon'' is an extinct genus of buchanosteid arthrodire placoderm. Its fossils have been found in Emsian-aged marine strata from the Taemas-Wee Jasper reef of New South Wales, Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ... and the type species is ''G. australianum''. The holotype was discovered near the Goodradigbee River by Harry A. Toombs and was described by White (1978).White, E. I. (1978). The larger arthrodiran fishes from the area of Burrinjuck Dam, N. S. W. ''Transactions of the Zoological Society of London'' 34: 149–262. References Buchanosteidae Placoderms of Australia Fossil taxa described in 1978 {{Placoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
