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Hedstroemia (trilobite)
''Hedstroemia '' is a genus of trilobites in the order Proetida known from the Silurian period of Europe, Asia, and North America. Taxonomic history The genus ''Hedstroemia'' was named in 1978. The type species designated was ''Hedstroemia delicatus'', which had originally been described as ''Proetus delicatus'' in 1923. In 1990 the subgenus ''Pachyproetus'' was proposed to accommodate a single species, ''P. pachydermata.'' In 1994, the genus ''Milesdavis'' was proposed based on incomplete fossils consisting of the pygidium (rear segment) of three individuals. The genus was named after musician Miles Davis, and the type species, ''Milesdavis eldredgei'', was named in honor of the paleontologist Niles Eldredge. In 1997, ''Milesdavis'' and the subgenus ''Pachyproetus'' were recognized as junior synonyms of ''Hedstroemia'', by paleontologist Jonathan Adrain, who regarded the type species of both as ingroup ''Hedstroemia''. Species Several species of ''Hedstroemia'' are recognized ...
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Species
In biology, a species is the basic unit of Taxonomy (biology), 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 sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ...
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Fossil Taxa Described In 1978
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ...
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Proetida Genera
Proetida is an order of trilobite that lived from the Ordovician to the Permian. It was the last order of trilobite to go extinct, finally dying out in the Permian-Triassic extinction event. Description These typically small trilobites resemble those of the order Ptychopariida, from which the new order Proetida was separated in 1975 by Fortey and Owens. Like the order Phacopida, the proetids have exoskeletons that sometime have pits or small tubercles, especially on the glabella (middle portion of the head). Because of their resemblance to the Ptychopariida in some features, the proetids are included in the subclass Librostoma. Unlike the trilobites of the phacopid suborder Phacopina, whose eyes are schizochroal, the proetids have the more common holochroal eyes. These eyes are characterized by close packing of biconvex lenses beneath a single corneal layer that covers all of the lenses. Each lens is generally hexagonal in outline and in direct contact with the others. They ...
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Proetidae
Proetidae is a family of proetid trilobites. The first species appeared in the Upper Ordovician, and the last genera survived until the Middle Permian. However, if the closely related family Phillipsiidae is actually a subfamily of Proetidae, then the proetids of Proetidae survive until the end of the Permian, where the last perish during the Permian–Triassic extinction event. Genera Proetidae ostensibly contains these following genera, though many may be placed in Phillipsiidae if the latter is, indeed, a distinct family. *'' Aayemenaytcheia'' *'' Aceroproetus'' *'' Alaskalethe'' *'' Altajaspis'' *'' Anambon'' *'' Anglibole'' *'' Angustibole'' *'' Anujaspis'' *'' Appendicysta'' *'' Aprathia'' *'' Archaeocoryphe'' *'' Ascetopeltis'' *'' Astroproetus'' (syn=''Xiushuiproetus'', ''Zhejiangoproetus'') *'' Australokaskia'' *'' Bailielloides'' *'' Bapingaspis'' *'' Basidechenella'' *'' Beleckella'' *'' Belgibole'' *'' Benesovella'' *'' Bitumulina'' *'' Blodgettia'' *'' Bohemiproet ...
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Author Citation (zoology)
In zoological nomenclature, author citation refers to listing the person (or team) who first makes a scientific name of a taxon available. This is done in a scientific work while fulfilling the formal requirements under the International Code of Zoological Nomenclature ("the Code"). According to Article 51.1 of the Code, "the name of the author does not form part of the name of a taxon and its citation is optional, although customary and often advisable", however recommendation 51A suggests: "The original author and date of a name should be cited at least once in each work dealing with the taxon denoted by that name. This is especially important and has a unique character between homonyms and in identifying species-group names which are not in their native combinations". For the seek of information retrieval, the author citation and year appended to the scientific name, e.g. genus-species-author-year, genus-author-year, family-author-year, etc., is often considered a "de facto" un ...
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Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago (Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' (" coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian lin ...
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Bohemia
Bohemia ( ; cs, Čechy ; ; hsb, Čěska; szl, Czechy) is the westernmost and largest historical region of the Czech Republic. Bohemia can also refer to a wider area consisting of the historical Lands of the Bohemian Crown ruled by the Bohemian kings, including Moravia and Czech Silesia, in which case the smaller region is referred to as Bohemia proper as a means of distinction. Bohemia was a duchy of Great Moravia, later an independent principality, a kingdom in the Holy Roman Empire, and subsequently a part of the Habsburg monarchy and the Austrian Empire. After World War I and the establishment of an independent Czechoslovak state, the whole of Bohemia became a part of Czechoslovakia, defying claims of the German-speaking inhabitants that regions with German-speaking majority should be included in the Republic of German-Austria. Between 1938 and 1945, these border regions were joined to Nazi Germany as the Sudetenland. The remainder of Czech territory became ...
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Emsian
The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan, above the contact with the Madmon Formation. In North America the Emsian Stage is represented by Sawkill or Sawkillian time. Biological events During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal as ...
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Much Wenlock Limestone Formation
The Much Wenlock Limestone Formation is a series of Silurian limestone beds that date back to the Homerian age, the later part of the Wenlock epoch.{{cite web , url=http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=WEL , title=Much Wenlock Limestone Formation , publisher=British Geological Survey , work=The BGS Lexicon of Named Rock Units , date=2013 , accessdate=11 July 2013 The formation comprises nodular to thinly bedded limestones, with variable development of reef bodies that can be found exposed at Wenlock Edge and in a small area near Dudley, England known as Wren's Nest. The formation is made up of three different members which have been classified as the Lower Quarried Limestone Member, the Nodular Beds Member and the Upper Quarried Limestone Member.Dorning, K. J. 1983. Palynology and stratigraphy of the Much Wenlock Limestone Formation, Dudley, Central England. Mercian Geologist, 20, 31-40. Many of the members can be subdivided into separate lithofacies that would ha ...
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Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ...
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Junior Synonyms
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnaeus was the first to give a scientific name (under the currently used system of scientific nomenclature) to the Norway spruce, which he called ''Pinus abies''. This name is no longer in use, so it is now a synonym of the current scientific name, ''Picea abies''. * In zoology, moving a species from one genus to another results in a different binomen, but the name is considered an alternative combination rather than a synonym. The concept of synonymy in zoology is reserved for two names at the same rank that refers to a taxon at that rank - for example, the name ''Papilio prorsa'' Linnaeus, 1758 is a junior synonym of ''Papilio levana'' Linnaeus, 1758, being names for different seasonal forms of the species now referred to as ''Araschnia leva ...
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