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Cyathaspidid
Cyathaspidida is a taxon of extinct cyathaspidiform heterostracan agnathans whose fossils are found in Silurian to Lower Devonian marine strata of Europe and North America.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. In life, they are thought to be benthic animals that lived most of their lives either mostly buried in or resting directly on top of the substrate. Taxonomy The cyathaspidids of Cyathaspidida were tadpole-like animals with drum-shaped, cigar-shaped or wedge-shaped cephalothoraxes, and were anatomically similar to several other heterostracan groups. However, with some groups, such as the traquairaspids, cardiopeltids, and corvaspidids, this similarity appears to be superficial. With other groups, namely the tolypelepidids, the similarity suggests a close relationship. The type genus of the tolypelepidids, '' Tolypelepis'', in particular, was determined to be the sister-taxon of C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyathaspidiformes
Cyathaspidiformes is an extinct order of heterostracan vertebrates known from extensive fossil remains primarily from Silurian to Early Devonian strata of Europe, and North America, and from Early Devonian marine strata of Siberia. Anatomy Like their descendants, the pteraspidids, all cyathaspidiform heterostracans had the cephalothorax enclosed in armor, formed from several plates, including dorsal, ventral, a dorsal spine derived from a scale, and a large, scale-covered tail. Thus, the living animals would have resembled tadpoles encased in massive armor. The majority of taxa have the rostral and pineal plates fused or merged with the dorsal plate, and in the amphiaspidids, all the plates of the cephalothorax were fused together into a single "muff-like" unit. Unlike the pteraspidids, all cyathaspidiforms are thought to be almost uniformly benthic in lifestyle, though only the amphiaspids and the ctenaspids are thought to be burrowers. Taxonomy The taxonomy of Cyathaspidifo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capitaspis
''Capitaspis'' is an extinct genus of cyathaspidine cyathaspidid heterostracan jawless vertebrate known from the Late Silurian Somerset Island Formation ( Pridolian epoch) of the Northwest Territories, Canada. It contains a single species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ..., ''Capitaspis giblingi''. It is most closely related to '' Pionaspis''. References Cyathaspidiformes genera Monotypic fish genera Fossil taxa described in 2013 Cyathaspidida Silurian jawless fish Fossils of Canada Paleontology in the Northwest Territories {{silurian-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariaspidae
Ariaspidae is a family of extinct cyathaspidiform heterostracan agnathans in the suborder Cyathaspidida. Family Ariaspidae contains ''Ariaspis'', and its sister-taxa originally contained within Anglaspididae/Anglaspidinae, including ''Anglaspis ''Anglaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Europe, from the late Silurian period until the genus' extinction during the Early Devonian. As with other cyathaspidiforms, i ...'', '' Listraspis'', '' Liliaspis'', and '' Paraliliaspis''.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. References * Phylogenetic patterns in the heterostracan families Cyathaspidae, Ariaspidae and Ctenaspidae. Lundgren Mette and Blom Henning, The 2nd Wiman meeting : Carl Wiman's Legacy: 100 years of Swedish Palaeontology : Uppsala 17–18 November 2011, 16-17 p. Cyathaspidida Prehistoric jawless fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenaspidae
Ctenaspidae is a family of extinct cyathaspidiform heterostracan agnathans in the suborder Cyathaspidida Cyathaspidida is a taxon of extinct cyathaspidiform heterostracan agnathans whose fossils are found in Silurian to Lower Devonian marine strata of Europe and North America.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cya .... If Amphiaspidida can be ignored as a daughter-taxon, the family Ctenaspidae contains '' Ctenaspis'' and its various sister-taxa originally contained within both Ctenaspididae and Ctenaspididae, including '' Allocryptaspis'', '' Alainaspis'', '' Zaphoctenaspis'', '' Arctictenaspis'', and '' Boothiaspis'', which was first described as a "Canadian amphiaspid."Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. References Cyathaspidida Prehistoric jawless fish families {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglaspis
''Anglaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Europe, from the late Silurian period until the genus' extinction during the Early Devonian. As with other cyathaspidiforms, individuals of ''Anglaspis'' had dorsal and ventral plates covering the forebody, gill pouches, and nasal openings that lay on the roof of the oral cavity. Late Silurian species of ''Anglaspis'' are found in marine strata of Wales and England, while most of the Early Devonian species are found in the Devonian-aged strata of Spitsbergen island, in Svalbard, Norway. Taxonomy ''Anglaspis'' was, at various times, placed in the families Cyathaspididae, Poraspididae, and in its own family, Anglaspididae. Currently, it is placed in Ariaspidae with ''Ariaspis ''Ariaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Canada and Europe from the late Silurian period until its extinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tolypelepidida
Tolypelepidida is an extinct order (biology), order of heterostraci, heterostracan vertebrates. These armored jawless fish superficially resemble their relatives, the Cyathaspidiformes, cyathaspids, though, researchers place the tolypelepids as a sister group to the cyathaspids and the pteraspidids (and both groups' daughter taxa).Philippe Janvier, Janvier, Philippe (1997Heterostraci''The Tree of Life Web Project''. A recent study by Lundgren and Blom in 2013 implies that the order is paraphyly, paraphyletic, with the type genus, ''Tolypelepis'', being the sister taxon of Cyathaspidiformes.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. The typical tolypelepid had a carapace formed from dorsal and ventral plates, and a scaly tail. References Heterostraci Prehistoric jawless fish orders Devonian jawless fish Silurian jawless fish Silurian first appearances Pridoli taxonomic orders Early Devonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poraspis
''Poraspis'' is an extinct genus of heterostracan. Fossils are found in Late Silurian and Early Devonian marine strata of Norway, Canada and the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori .... References Cyathaspidida Silurian first appearances Devonian extinctions Fossil taxa described in 1930 Paleozoic jawless fish Paleozoic fish of North America Cyathaspidiformes genera {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
