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Elpistostegalians
Elpistostegalia or Panderichthyida is an order of prehistoric lobe-finned fishes which lived during the Middle Devonian to Late Devonian period (about 385 to 374 million years ago). They represent the advanced tetrapodomorph stock, the fishes more closely related to tetrapods than the osteolepiform fishes. The earliest elpistostegalians, combining fishlike and tetrapod-like characters, are sometimes called fishapods, a phrase coined for the advanced elpistostegalian ''Tiktaalik''. Through a strict cladistic view, the order includes the terrestrial tetrapods. Palaeobiology of the elpistostegalians A rise in global oxygen content allowed for the evolution of large, predatory fish that were able to exploit the shallow tidal areas and swamplands as top predators. Several groups evolved to fill these niches, the most successful were the elpistiostegalians. In such environments, they would have been challenged by periodic oxygen deficiency. In comparable modern aquatic environments li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panderichthys
''Panderichthys'' is a genus of extinct sarcopterygian (lobe-finned fish) from the late Devonian period, about 380 Mya. ''Panderichthys'', which was recovered from Frasnian (early Late Devonian) deposits in Latvia, is represented by two species. ''P. stolbovi'' is known only from some snout fragments and an incomplete lower jaw. ''P. rhombolepis'' is known from several more complete specimens. Although it probably belongs to a sister group of the earliest tetrapods, ''Panderichthys'' exhibits a range of features transitional between tristichopterid lobe-fin fishes (e.g., ''Eusthenopteron'') and early tetrapods. It is named after the German-Baltic paleontologist Christian Heinrich Pander. Possible tetrapod tracks dating back to before the appearance of ''Panderichthys'' in the fossil record were reported in 2010, which suggests that ''Panderichthys'' is not a direct ancestor of tetrapods, but nonetheless shows the traits that evolved during the fish-tetrapod evolution Discovery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qikiqtania
''Qikiqtania'' (pronounced "kick-kiq-tani-ahh") is an extinct genus of elpistostegalian tetrapodomorph from the Late Devonian (early Frasnian stage) Fram Formation of Nunavut, Canada. The genus contains a single species, ''Q. wakei'', known from a partial skeleton. Analysis of the fin bones suggests that ''Qikiqtania'' was well-suited to swimming, and likely incapable of walking or supporting itself out of the water, as has been suggested for the closely related ''Tiktaalik''. Discovery and naming The holotype specimen of ''Qikiqtania'', NUFV 137, was discovered in 2004 in layers of the late Devonian (Frasnian)-dated Fram Formation of southern Ellesmere Island, Nunavut, Canada. The holotype specimen consists of lower jaws, partial left upper jaw and palate, gulars, ceratohyals, an articulated left pectoral fin and various articulated scales. The fossil remains of Qikiqtania were discovered east of the site where Tiktaalik was discovered, but from a slightly lower horizon in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panderichthyidae
Panderichthyidae is a family of prehistoric lobe-finned fishes which lived during the Late Devonian period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept .... References Elpistostegalians Late Devonian fish Devonian bony fish Prehistoric lobe-finned fish families Late Devonian first appearances Late Devonian animals Late Devonian extinctions {{Devonian-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle 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 al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per E
Per is a Latin preposition which means "through" or "for each", as in per capita. Per or PER may also refer to: Places * IOC country code for Peru * Pér, a village in Hungary * Chapman code for Perthshire, historic county in Scotland Math and statistics * Rate (mathematics), ratio between quantities in different units, described with the word "per" * Price–earnings ratio, in finance, a measure of growth in earnings * Player efficiency rating, a measure of basketball player performance * Partial equivalence relation, class of relations that are symmetric and transitive * Physics education research Science * Perseus (constellation), standard astronomical abbreviation * Period (gene) or ''per'' that regulates the biological clock and its corresponding protein PER * Protein efficiency ratio, of food * PER or peregrinibacteria, a candidate bacterial phylum Media and entertainment * PeR (band), a Latvian pop band * ''Per'' (film), a 1975 Danish film Transport * IATA cod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoological Journal Of The Linnean Society
The ''Zoological Journal of the Linnean Society'' is a monthly peer-reviewed scientific journal covering zoology published by Oxford University Press on behalf of the Linnean Society. The editor-in-chief is Maarten Christenhusz (Linnean Society). It was established in 1856 as the ''Journal of the Proceedings of the Linnean Society of London. Zoology'' and renamed ''Journal of the Linnean Society of London, Zoology'' in 1866. It obtained its current title in 1969. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 3.286. References External links * Zoology journals Linnean Society of London Monthly journals Academic journa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eifelian
The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American subdivisions of the Eifelian Stage include Southwood, and part of Cazenovia (or Cazenovian). Name and definition The Eifelian is named after the Eifel Mountains of Western Germany, which exposed the GSSP section at the Wetteldorf Richtschnitt outcrop. The base of the Eifelian is defined by the start of the '' Polygnathus partitus'' conodont zone. This layer lies within the Upper Heisdorf Formation, below the base of the Lauch Formation. Extinctions The end of the Eifelian was marked by a biological crisis known as the Kačák Event, a two-part interval of extinction which led to ecological turnover among ammonoids, conodonts, and other free-swimming animals. In deep marine waters, the event is indicated by anoxic black shales. Ther ... [...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] |
Frasnian
The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during the Frasnian Stage, particularly in western Canada and Australia. On land, the first forests were taking shape. In North America, the Antler orogeny peaked, which were contemporary with the Bretonic phase of the Variscan orogeny in Europe. The Frasnian coincides with the second half of the "charcoal gap" in the fossil record, a time when atmospheric oxygen levels were below 13 percent, the minimum necessary to sustain wildfires. North American subdivisions of the Frasnian include * West Falls Group * Sonyea Group * Genesee Group Name and definition The Frasnian Stage was proposed in 1879 by French geologist Jules Gosselet Jules-Auguste Gosselet (19 April 1832 – 20 March 1916) was a French geologist born in Cambrai, France. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocranium
The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy. Structure Structurally, the endocranium consists of a boxlike shape, open at the top. The posterior margin exhibit the '' foramen magnum'', an opening for the spinal cord. The floor of the endocranium has several paired openings for the cranial nerves, and the anterior margin holds a spongy construction, allowing for the external nasal nerves to pass through. Romer, A.S. & T.S. Parsons. 1977. ''The Vertebrate Body.'' 5th ed. Saunders, Philadelphia. (6th ed. 1985) All bones of the structure derive from the cranial neural crest during fetal development. Endocranial elements in humans In humans and other mammals, the endocranium forms during fetal development as a cartilaginous neurocranium, that ossifies from several centers. Several of these bones merge, and in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
