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Stensioella
''Stensioella heintzi'' is an enigmatic placoderm of arcane affinity. It is only known from the Lower Devonian Hunsrück slate of Germany. The genus is named after Erik Stensiö, the species name honours Anatol Heintz. Anatomy ''Stensioella heintzi'' has an elongated body, a whip-like tail, and long, wing-like pectoral fins. In life, the animal would have looked vaguely like an elongated Chimaeridae, ratfish. Like the sympatric ''Gemuendina'', ''S. heintzi'' had armor made up of a complex mosaic of small, scale-like tubercles. Taxonomy ''Stensioella'' is tentatively placed within Placodermi as being among the most basal of all placoderms, as from what can be discerned from the only whole specimen found, the shoulder joints of its armor appear to be very similar to other placoderms. Despite this detail, coupled with superficial similarities in skull plates, and gross, superficial similarities between its tubercles, and the tubercles of the rhenanids, some paleontologists believ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placoderms Of Europe
Placoderms (from Ancient Greek πλάξ [''plax'', ''plakos''] 'Plate (animal anatomy), plate' and δέρμα [''derma''] 'skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian geological period, periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armour (zoology), armoured plates (hence the name), and the rest of the body was scale (zoology), scaled or naked depending on the species. Placoderms were among the first jawed fish (their fish jaw, jaws likely Evolution, evolved from the first pair of gill arches), as well as the first vertebrates to have true tooth, teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homology (biology), homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, ''Incisoscutum'', ''M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placoderm Genera
Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos''' plate' and δέρμα 'derma'''skin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armoured plates (hence the name), 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 pair of gill arches), as well as the first vertebrates to have true teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, '' Incisoscutum'', '' Materpiscis'' and '' Austroptyctodus'', represent the oldest known examples of live birth. Placoderms are thought to be paraphyletic, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placoderm
Placoderms (from Ancient Greek πλάξ [''plax'', ''plakos''] 'Plate (animal anatomy), plate' and δέρμα [''derma''] 'skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian geological period, periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armour (zoology), armoured plates (hence the name), and the rest of the body was scale (zoology), scaled or naked depending on the species. Placoderms were among the first jawed fish (their fish jaw, jaws likely Evolution, evolved from the first pair of gill arches), as well as the first vertebrates to have true tooth, teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homology (biology), homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, ''Incisoscutum'', ''M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocephali
Holocephali (Sometimes spelled Holocephala; Romanization of Greek, Greek for "complete head" in reference to the fusion of Palatoquadrate, upper jaw with the rest of the skull) is a Subclass (biology), subclass of Chondrichthyes, cartilaginous fish. While the only living holocephalans are three families within a single Order (biology), order which together are commonly known as chimaeras, the group includes many extinct orders and was far more diverse during the Paleozoic and Mesozoic Era (geology), eras. The earliest known fossils of holocephalans date to the Middle Devonian period, and the group likely reached its peak diversity during the following Carboniferous period. Molecular clock studies suggest that the subclass diverged from its closest relatives, Elasmobranchii, elasmobranchs such as sharks and Batomorphi, rays, during the Early Devonian or Silurian period. Extinct holocephalans are typically divided into a number of orders, although the interrelationships of these gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erik Stensiö
Prof Erik Helge Osvald Stensiö HFRSE (2 October 1891 – 11 January 1984), né Andersson, was an influential Swedish paleozoologist and founder of the so-called "Stockholm School" of vertebrate paleontology. He later took his new surname, Stensiö, from his place of origin and is occasionally referred to with both names (as Erik Andersson Stensiö, Erik A. Stensiö or Erik A:son Stensiö) Life Erik Helge Oswald Andersson, as his original name was, was born in the village of Stensjö by in Döderhult parish in Kalmar County, the son of Johan Fredrik Andersson (d.1907), a farmer, and his wife, Otilia Maria Erlandson (d.1940). He was educated at Linköping Gymnasium. He then studied science at the University of Uppsala, graduating BSc in 1912. He received his Ph.D. and a docentship in paleontology from Uppsala University in 1921 and became professor and keeper at the Zoopaleontological (later called the Paleozoological) department of the Swedish Museum of Natural History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimaeridae
The Chimaeridae, or short-nosed chimaeras, are a family (biology), family of cartilaginous fish. They resemble other Chimaeriformes, chimaeras in general form and habits, but have short, rounded snouts, without the modifications found in related families. Many species have long, tapering tails, giving them an alternative name of ratfish. Shortnose Chimaera, chimaeras have a venomous spine on their backs, which is sufficiently dangerous to injure humans. They are found in temperate and tropical marine waters worldwide. Most species are restricted to depths below , but a few, notably the spotted ratfish and rabbit fish, can locally be found at relatively shallow depths. They range from in maximum total length, depending on species. Species The species are grouped into two genera and include: Family Chimaeridae * Genus ''Chimaera (genus), Chimaera'' Carl Linnaeus, Linnaeus, 10th edition of Systema Naturae, 1758 (Eocene-Recent) ** ''Chimaera argiloba'' Peter R. Last, Last, Will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimaera
Chimaeras are Chondrichthyes, cartilaginous fish in the order (biology), order Chimaeriformes (), known informally as ghost sharks, rat fish (not to be confused with rattails), spookfish, or rabbit fish; the last two names are also applied to Barreleye, Opisthoproctidae and Rabbitfish, Siganidae, respectively. At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks and ray (fish), rays, though their last common ancestor with them lived nearly 400 million years ago. Living species (aside from plough-nose chimaeras) are largely confined to deep water. Anatomy Chimaeras are soft-bodied, shark-like fish with bulky heads and long, tapered tails; measured from the tail, they can grow up to in length. Like other members of the class Chondrichthyes, chimaera skeletons are entirely cartilaginous, or composed of cartilage. Males use forehead denticles to grasp a female by a fin during copulation. The Branchial arch, gill arche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
