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Biceratopsidae
Biceratopsidae is an extinct family of redlichiid trilobites, with species of small to average size. Species of belonging to this family lived during the Toyonian stage (''Olenellus''-zone), 522–513 million years ago, in the former continent of Laurentia, including what are today the south-western United States and Canada. It contains the subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zool ... Biceratopsinae and Bristoliinae. Habitat The Biceratopsidae were probably marine bottom dweller, like all Olenellina. References Olenelloidea Trilobite families Cambrian trilobites Cambrian first appearances Cambrian Series 2 extinctions {{redlichiida-stub ...
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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 Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of ..., 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 Trilobite subfamilies {{Redlichiida-stub ...
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Olenelloidea
The Olenelloidea are a superfamily of trilobites, a group of extinct marine arthropods. They lived during the late Lower Cambrian and species occurred on all paleocontinents. Taxonomy Palmer and Repina assigned '' Gabriellus'' and '' Callavia'' to the Olenelloidea, but the ocular lobes in these two genera circumscribe the entire lateral border of the frontal lobe of the glabella, and thus, do not belong to this superfamily, but to the Judomioidea. Geyer assigned '' Cambropallas'' to the Olenelloidea, but it lacks the diagnostic features and appears to be closely related to '' Andalusiana'', and is now considered to be an advanced member of the Nevadioidea. Distribution In western Laurentia Fallotaspididae and Archaeaspididae proceed the first Olenelloidea. The Holmiidae occur at the late Atdabanian, and are contemporary with the Nevadioidea. They are followed by Biceratopsidae and Olenellidae. Description As with most early trilobites, the Olenelloidea have an almost ...
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Bristoliinae
The Bristoliinae is an extinct subfamily of trilobites, fossil marine arthropods, with species of small to average size. Species belonging to this subfamily lived during the Botomian and Toyonian stage (''Olenellus''-zone), 522-513 million years ago, in the former continent of Laurentia, including what are today Mexico, the Appalachian Mountains and the south-western United States, and Canada (Northwest Territories). Etymology The Bristoliinae are named for the type species '' Bristolia bristolensis''. Description The headshield (or cephalon) carries spines (called genal spines) of approximately 4-8 thorax segments long (measured parallel to the midline). The genal spines are attached in front of the back of the headshield. The central raised portion of the cephalon that represents the axis in the cephalon (or glabella) touches the flattened ledge that borders the cephalon. The furrows that separate border, eye ridges, glabella and its lobes are distinct. Communalities and ...
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Extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and recover. As a species' potential Range (biology), range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxon, Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the Fossil, fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if microorganisms are included. Notable extinct animal species include Dinosaur, non-avian dinosaurs, Machairodontinae, saber-toothed cats, and mammoths. Through evolution, species arise through the process of specia ...
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Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ...
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Redlichiida
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 ou ...
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Trilobite
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ...
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Toyonian
Cambrian Stage 4 is the still unnamed fourth 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 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 The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the International Stratigraphic Commission, is a daughter or major subcommittee grade scientific organization that concerns itself with stratigraphy, strati ... has not named the fourth stage of the Cambrian yet. In the widely used Siberian nomenclature st ...
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Laurentia
Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean terrane in northwest Scotland. During other times in its past, Laurentia has been part of larger continents and supercontinents and consists of many smaller terranes assembled on a network of early Proterozoic Orogenic belt, orogenic belts. Small microcontinents and oceanic islands collided with and Suture (geology), sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today. Etymology The craton is named after the Laurentian Shield, through the Laurentian Mountains, which received their name from the St. Lawrence River, named after Saint Lawrence of Rome. Interior platform In eastern and centra ...
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Subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zoological subfamily names with "-inae". Detarioideae is an example of a botanical subfamily. Detarioideae is a subdivision of the family Fabaceae (legumes), containing 84 genera. Stevardiinae is an example of a zoological subfamily. Stevardiinae is a large subdivision of the family Characidae, a diverse clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ... of freshwater fish. See also * International Code of Nomenclature for algae, fungi, and plants * International Code of Zoological Nomenclature * Rank (botany) * Rank (zoolo ...
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Trilobite Families
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ...
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