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Olenelloides
''Olenelloides armatus'' is an extinct, small sized (about long) olenelloid redlichiid trilobite arthropod. It lived during the later part of the Botomian stage, which lasted from approximately 524 to 518.5 million years ago. This faunal stage was part of the Cambrian Period. The most conspicuous feature is the hexagonal head shield that carries 6 ray-like spines.. Etymology The genus is named after its originally supposed close relationship with '' Olenellus''. The species epithet , a Latin adjective meaning 'armoured', is a reference to the fierce looking spines of the head shield. Occurrence ''Olenelloides armatus'' lived during the late Lower Cambrian deposits presumably contemporary with the middle ''Olenellus''-zone (''Wanneria'' subzone), that probably represents the late Botomian, approximately between 519 and 516 million years ago. Distribution ''Olenelloides armatus'' has been collected from the Fucoid Beds, Northern slopes of the Meall a'Ghiubhais, County R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biceratopsinae
The Biceratopsinae is an extinct subfamily of redlichiid trilobites within the family Biceratopsidae, with species of small to average size. Species belonging to this subfamily lived during the Toyonian stage (Upper ''Olenellus''-zone), 516-513 million years ago, in the former continent of Laurentia, including what are today the South-Western United States and Canada. Etymology The Biceratopsinae are named for the type species '' Biceratops nevadensis''. Habitat The Biceratopsinae were probably marine bottom dweller, like all Olenellina. References Cambrian trilobites Cambrian Series 2 first appearances Cambrian Series 2 extinctions Biceratopsidae Arthropod subfamilies {{Redlichiida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botomian
Cambrian Stage 4 is the still unnamed fourth Stage (geology), stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on Stratigraphy. One proposal is the First appearance datum, first appearance of two trilobite genera, ''Olenellus'' or ''Redlichia''. Another proposal is the first appearance of the trilobite species ''Arthricocephalus chauveaui''. Both proposals will set the lower boundary close to million years ago. The upper boundary corresponds to the beginning of the Wuliuan. Naming The International Commission on Stratigraphy has not named the fourth stage of the Cambrian yet. In the widely used Siberian nomenclature stage 4 would overlap with parts of the Botomian and Toyonian. Biostratigraphy The beginning of Cambrian Stage 4 has been tentatively correlated with the base of the European Leonian faunal stage and the base of the Sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite Zone
Trilobites are used as index fossils to subdivide the Cambrian period. Assemblages of trilobites define trilobite zones. The '' Olenellus''-zone has traditionally marked the top of the Lower Cambrian, and is followed by the '' Eokochaspis'' zone. The last two zones of the Middle Cambrian are the ''Bathyuriscus– Elrathina''-zone (contemporaneous with the Burgess Shale) and the subsequent '' Bolaspidella''-zone (starting at the base of the Drumian stage). These are overlain by the lowermost Upper Cambrian '' Cedaria''-zone. Alternative zoning names place the Burgess Shale in the ''Peronopsis bonnerensis''-zone, which is underlain by the '' Oryctocephalus indicus''-zone (e.g. Spence Shale) and overlain (perhaps not directly) by the ''Ptychagnostus punctuosus''-zone. The lower Middle Cambrian '' Glossopleura''-zone (Spence Shale) is above the '' Albertella''-zone. The '' Elvinia''-zone is upper Cambrian. Subdivision of the ''Olenellus''-zone Recently, it has been propos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic Arthropod Genera
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa. Examples Just as the term ''monotypic'' is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are: Plants * In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, ''Amborella'', and in this genus there is only one species, namely ''Amborella trichopoda.'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Trilobites
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redlichiida Genera
Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are ''Fallotaspis'' (suborder Olenellina), and ''Lemdadella'' (suborder Redlichiina), both belonging to this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. In terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichiid trilobites died out before the end of the Middle Cambrian. Description Most redlichiids are rather flat (or have low dorso-ventral convexity) and their exoskeleton typically has an oval outline, abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detritivore
Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, vertebrates and plants that carry out coprophagy. By doing so, all these detritivores contribute to decomposition and the nutrient cycles. They should be distinguished from other decomposers, such as many species of bacteria, fungi and protists, which are unable to ingest discrete lumps of matter, but instead live by absorbing and metabolizing on a molecular scale ( saprotrophic nutrition). The terms ''detritivore'' and ''decomposer'' are often used interchangeably, but they describe different organisms. Detritivores are usually arthropods and help in the process of remineralization. Detritivores perform the first stage of remineralization, by fragmenting the dead plant matter, allowing decomposers to perform the second stage of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olenellidae
Olenellidae is an extinct family of redlichiid trilobite arthropods. Olenellids lived during the late Lower Cambrian (Botomian/Toyonian) in the so-called ''Olenellus''-zone in the former paleocontinent of Laurentia plus parts of what became the Famatinian orogen in what is now Argentina. This family can be distinguished from most other Olenellina by the partial merger of the frontal (L3) and middle pair (L2) of lateral lobes of the central area of the cephalon, that is called glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to ..., creating two isolated slits. Key to the subfamilies References Olenelloidea Trilobite families Cambrian first appearances Cambrian Series 2 extinctions {{Redlichiida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paedomorphosis
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology The origins of the concept of neoteny have been traced to the Bible (as argued by Ashley Monta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ben Peach
Benjamin Neeve Peach (6 September 1842 – 29 January 1926) was a British geologist. Life Peach was born at Gorran Haven in Cornwall on 6 September 1842 to Jemima Mabson and Charles William Peach, an amateur British naturalist and geologist. He was educated at the Royal School of Mines in London and then joined the Geological Survey in 1862 as a geologist, moving to the Scottish branch in 1867. He is best remembered for his work on the Northwest Highlands and Southern Uplands with his friend and colleague John Horne, where they resolved the long-running "Highlands Controversy" with their 1907 publication of '' The Geological Structure of the North-West Highlands of Scotland''. In 1881 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were Archibald Geikie, Sir Charles Wyville Thomson, Peter Guthrie Tait and Robert Gray. He won the Society's Neill Prize for the period 1883–86. He served as the Society's Vice President from 1912 to 1917. He was e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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