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Emuelloidea
Emuelloidae are a small superfamily of trilobites, a group of extinct marine arthropods, that lived during the late Lower Cambrian (late Botomian) of the East Gondwana supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ..., in what are today South-Australia and Antarctica. Emuelloidea can be recognized by having a prothorax consisting of 3 or 6 segments, the most backward one of which is carrying very large trailing spines. Behind it is the so-called opistothorax. There are two families, the Emuellidae (with a prothorax of six segments) and the Megapharanaspididae (with a prothorax of three segments). References Cambrian trilobites Redlichiina Cambrian Series 2 first appearances Cambrian Series 2 extinctions Arthropod superfamilies Trilobite superfamili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megapharanaspididae
''Megapharanaspis nedini'' is a small (maximally ) trilobite of the superfamily Emuelloidea, within which it occupies a family on its own. Its fossils have been found in the Lower Cambrian of South-Australia. Etymology The genus name composed of the Greek μέγας (mega), meaning ''great'', pharangos, meaning gully, and ἀσπίς (aspis) shield, referencing Big Gully on Kangaroo Island, the only known site where fossils of ''Megapharanaspis'' were collected. The species epithet An epithet (, ), also a byname, is a descriptive term (word or phrase) commonly accompanying or occurring in place of the name of a real or fictitious person, place, or thing. It is usually literally descriptive, as in Alfred the Great, Suleima ... ''nedini'' is in honor of Dr. Chris Nedin. References Cambrian trilobites of Australia Emuelloidea Redlichiida genera Cambrian genus extinctions {{Redlichiida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emuellidae
Emuellidae are a small family of trilobites, a group of extinct marine arthropods, that lived during the late Lower Cambrian (late Botomian) of the East Gondwana supercontinent, in what are today South-Australia and Antarctica. Description Emuellidae can be recognized among trilobites in having a set of unique features. The headshield or cephalon has large genal spines reaching as far back as the 3rd to 6th segment of the thorax. The eye-ridges contact the back of the frontal lobe of the glabella and extend laterally and backwards, roughly parallel to the frontal and lateral rim of the cephalon. There are small, clearly incised pits at the junction between the eye-ridge and the frontal lobe of the cephalic axis (or glabella). The thorax reaches its greatest width at the 6th segment. The frontal part or prothorax consists of 6 segments, with number 5 and 6 fused, and the 6th carrying very large trailing spines. The rear part or opistothorax consists of a variable but extremely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redlichiina
Redlichiina is a suborder of the order Redlichiida of Trilobites. The suborder contains three superfamilies: Emuelloidea, Redlichioidea and Paradoxidoidea. These trilobites are some of the oldest trilobites known. They originated at the beginning of the Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ... Period and disappeared (possibly by evolving into members of the Ptychopariida order) at the end of the middle Cambrian. Physiology Cephalon: Opisthoparian facial sutures. Early forms tend to have tapering, conical glabella with furrows extending far backwards while later forms with glabella expanding forwards to inflated frontal lobe. The hypostome is conterminant (e.g., Redlichia) or natant (e.g., Dolerolenus). The rostral plate is narrower than in suborder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botomian
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent. Moving under the forces of plate tectonics, supercontinents have assembled and dispersed multiple times in the geologic past. According to modern definitions, a supercontinent does not exist today; the closest is the current Afro-Eurasian landmass, which covers approximately 57% of Earth's total land area. The last period in which the continental landmasses were near to one another was 336 to 175 million years ago, forming the supercontinent Pangaea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Series 2 Extinctions
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly incre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zealandia, Arabian Peninsula, Arabia, and the Indian subcontinent. Gondwana was formed by the Accretion (geology), accretion of several cratons (large stable blocks of the Earth's crust), beginning with the East African Orogeny, the collision of India and Geography of Madagascar, Madagascar with East Africa, and culminating in with the overlapping Brasiliano orogeny, Brasiliano and Kuunga orogeny, Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Paleozoic Era, covering an area of some , about one-fifth of the Earth's surface. It fused with Laurasia during the Carboniferous to form Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
