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Agnostus
''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian (about 506 to 492 million years ago). It is the type genus of the family Agnostidae and is subdivided into two subgenera, ''Agnostus'' and ''Homagnostus''. Etymology ''Agnostus'' is from the Ancient Greek άγνωστος (''ágnostos'') "unknown", and reflects the fact that early paleontologists did not know what type of animal with which they were confronted. The species epithet has this origin: * ''pisiformis'' derives from the Latin ''pīsum'' which means "pea", and ''forma'' meaning "shape", for its globe-like appearance when rolled. Description ] Like all Agnostida, ''Agnostus'' is diminutive and the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) are around the same size (or isopygous) and outline. As in all Agnostina, ''Agnostus'' has two thorax segments. When Agnostina ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostus Pisiformis Frontal Thorax Limbs Linedrawing
''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian (about 506 to 492 million years ago). It is the type genus of the family (biology), family Agnostidae and is subdivided into two subgenera, ''Agnostus'' and ''Homagnostus''. Etymology ''Agnostus'' is from the Ancient Greek άγνωστος (''ágnostos'') "unknown", and reflects the fact that early paleontologists did not know what type of animal with which they were confronted. The species epithet has this origin: * ''pisiformis'' derives from the Latin ''pīsum'' which means "pea", and ''forma'' meaning "shape", for its globe-like appearance when rolled. Description ] Like all Agnostida, ''Agnostus'' is diminutive and the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) are around the same size (or Pygidium#Trilobites, isopygous) and outline. As in all Agnostina, ''Agnostus'' has t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostus Leg
''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian (about 506 to 492 million years ago). It is the type genus of the family Agnostidae and is subdivided into two subgenera, ''Agnostus'' and ''Homagnostus''. Etymology ''Agnostus'' is from the Ancient Greek άγνωστος (''ágnostos'') "unknown", and reflects the fact that early paleontologists did not know what type of animal with which they were confronted. The species epithet has this origin: * ''pisiformis'' derives from the Latin ''pīsum'' which means "pea", and ''forma'' meaning "shape", for its globe-like appearance when rolled. Description ] Like all Agnostida, ''Agnostus'' is diminutive and the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) are around the same size (or isopygous) and outline. As in all Agnostina, ''Agnostus'' has two thorax segments. When Agnostina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostidae
Agnostidae is a family of Agnostida trilobites. Like all Agnostina, they were eyeless and bore only two thoracic segments. They ranged in benthic waters across the globe from 508 to 461 million years ago, containing the following genera, among others: *'' Acmarhachis'' *''Agnostus ''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian (about 506 to 492 million years ago). It is the type genus of the family Agnostidae and is sub ...'' *'' Aistagnostus'' *'' Anglagnostus'' *'' Biciragnostus'' *'' Connagnostus'' *'' Distagnostus'' *'' Eolotagnostus'' *'' Gymnagnostus'' *'' Homagnostus'' *'' Idolagnostus'' *'' Innitagnostus'' *'' Ivshinagnostus'' *'' Kymagnostus'' *'' Lotagnostus'' *'' Micragnostus'' *'' Obelagnostus'' *'' Oncagnostus'' *'' Peronopsis'' *'' Phalacroma'' *'' Phalagnostus'' *'' Quadrahomagnostus'' *'' Raragnostus'' *'' Semagnostus'' *'' Strictagnostus'' *'' Trilobagnostu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acadagnostus
''Acadagnostus'' is a genus of trilobite from the Middle Cambrian, with 7 species currently recognized. The type species ''A. acadicus'' has the widest distribution known from any peronopsid (with ''Peronopsis, Peronopsis integer'' and ''P. scutalis'') and has been found in North America, Greenland, England, Western Europe, Eastern Europe, Central Asia, the Altai Mountains, the Siberian shield, China, and Australia. Etymology * ''ancisa'' is Latin meaning 'cut round', referring to the shape of the rear pygidial margin. * ''australis'' is Latin for 'southern'. * ''certus'' is Latin meaning 'definite' or 'sure'. * ''syrma'' is Ancient Greek meaning 'robe with a train', indicating the wide pygidial border in the rear. Description Like all Agnostida, ''Acadagnostus'' is diminutive, with the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) of approximately the same size (or Pygidium#Trilobites, isopygous) and outline. Like all Agnostina ... [...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. The stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endopodite
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments artic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exopodite
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments arti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Podomere
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ogive
An ogive ( ) is the roundly tapered end of a two-dimensional or three-dimensional object. Ogive curves and surfaces are used in engineering, architecture and woodworking. Etymology The earliest use of the word ''ogive'' is found in the 13th century sketchbook of Villard de Honnecourt, from Picardy in northern France. The ''Oxford English Dictionary'' considers the French term's origin obscure; it might come from the Late Latin , the feminine perfect passive participle of , meaning the one who has met or encountered the other. However, Merriam-Webster's dictionary says it is from the "Middle English stone comprising an arch, from Middle French diagonal arch". Types and use in applied physical science and engineering In ballistics or aerodynamics, an ogive is a pointed, curved surface mainly used to form the approximately streamlined nose of a bullet or other projectile, reducing air resistance or the drag of air. In fact the French word ''ogive'' can be translated as "nose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incertae Sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by ' (of uncertain family), ' (of uncertain suborder), ' (of uncertain order) and similar terms. Examples *The fossil plant '' Paradinandra suecica'' could not be assigned to any family, but was placed ''incertae sedis'' within the order Ericales when described in 2001. * The fossil ''Gluteus minimus'', described in 1975, could not be assigned to any known animal phylum. The genus is therefore ''incertae sedis'' within the kingdom Animalia. * While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves ''incertae sedis''. It was later agreed to place them in a separate order, Cathartiformes. * Bocage's longbill, ''Motacilla bocagii' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armin Öpik
Armin Aleksander Öpik (24 June 1898, in Kunda – 15 January 1983, in Canberra) was an Estonian paleontologist who spent the second half of his career (from 1948) at the Bureau of Mineral Resources in Australia. Early life He was born on at the village Lontova, now a quarter of Kunda in Estonia and died in Canberra. His father Karl Heinrich Öpik was a harbormaster and his mother was Leontine Johanna Öpik (''née'' Freiwald). He had five brothers and one sister. His oldest brother Paul Öpik, later a director of the Bank of Estonia, introduced Armin to fossils. His sister Anna was a philologist, fluent in 14 languages, including Sanskrit. His brother Oskar was a diplomat. His brother Ernst was a famous astronomer. During the First World War he got to know Barbara Potaschko (died in 1977, Canberra). They had one son and three daughters. Öpik is mostly known for his work on the Cambrian and Lower Ordovician stratigraphy and paleontology of northern Australia. Studies and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnus Bromelius
Magnus Bromelius, ennobled Von Bromell, born in Stockholm in 1679, died in 1731, was a Swedish physician and paleontologist. He was the son of the physician and botanist Olof Bromelius and Agnes Svinhufvud af Qvalstad. Bromelius became a doctor of medicine in 1703 in Reims, and was appointed a member of the Collegium medicum in 1705. At the same time he inherited a considerable fortune, which allowed him to devote his time to enlarge the collections of natural objects, coins and medals, he inherited from his father. He was appointed Professor of Anatomy in Stockholm in 1716, but soon left for a position at Collegium medicum, where he became president in 1724. He was elevated in 1726 to nobility. Bromelius wrote many papers in numismatics, medicine and science. Some of them are contained in the "Acta Literaria et Scientiarum Sveciæ", including "Introduction to essential knowledge to recognize and order all sorts of rocks, metals and fossils, etc." (1730). According to Elias Frie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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