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Raphiophoridae
Raphiophoridae is a family of small to average-sized trilobites that first occurred at the start of the Ordovician and became extinct at the end of the Middle Silurian. Anatomy All raphiophorids are blind, with headshields (or cephalons) that are triangular to subcircular, and many carry long, trailing genal spines, a forward-directed rapier-like spine on the central raised area (or glabella), or both, with the glabella often inflated and the natural fracture lines (or sutures) of the cephalon coinciding with its margin. The thorax typically has five to seven segments (except for the genera ''Taklamakania'', ''Pseudampyxina'', ''Nanshanaspis'', and ''Kongqiangheia'', which have only 3). As mentioned before, all raphiophorids are blind. Many, if not most, genera have no eyes whatsoever, though a few, such as '' Lehnertia'', have vestigial tubercles that correspond to the compound eyes of their ancestors. Distribution Raphiophoridae currently includes two officially recog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampyx (trilobite)
''Ampyx'' is an Ordovician-Silurian genus of Asaphid trilobites of the family Raphiophoridae. Species of ''Ampyx'' are characterized by three extended spines on the head-shield, one spine derived from each free cheek, and one spine emanating from the glabellum. Species include ''Ampyx linleyensis'' ( Lanvirn-Caradoc series). Species of ''Ampyx'' grew to an average length of . Collective behaviour Fossils of the trilobite ''Ampyx priscus'', dating back about 480 million years ago, have been recently described as clustered in lines along the ocean floor. The animals were all mature adults, and were all facing the same direction as though they had formed a conga line or a peloton. It has been suggested they line up in this manner to migrate, much as spiny lobsters migrate in single-file queues. Or perhaps they are getting together for mating. The findings suggest animal collective behaviour has very early evolutionary origins.Vannier J, Vidal M, Marchant R, El Hariri K, Kourais ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanshanaspis
''Nanshanaspis'' is a genus of asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. Like all raphiophorids it is blind, with a headshield (or cephalon) that is subsemicircular, carrying genal spines and a forward directed spine on the central raised area (or glabella), with the front of the glabella inflated and the natural fracture lines (or sutures) of the cephalon coinciding with its margin. It is easily distinguished from most other raphiophorids by the 3 thorax segments. '' Pseudampyxina'', ''Taklamakania'', and ''Kongqiangheia ''Kongqiaoheia rotundata'' is an asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. ''K. rotundata'' was originally grouped with the so-called Taklamakaniinae, a paraphyletic group of ti ...'' also have only 3 such segments, while all other raphiophorid genera have at least 5 thorax segments, leading to the erection of the subfamily " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lonchodomas
''Lonchodomas'' is a genus of trilobites, that lived during the Ordovician. It was eyeless, like all raphiophorids, and had a long straight sword-like frontal spine, that gradually transforms into the relatively long glabella. Both the glabellar spine and the backward directed genal spines are subquadrate in section. ''Lonchodomas'' has five thorax segments and the pleural area of the pygidium has two narrow furrows. ''Lonchodomas'' occurred in what are today Argentina, Canada (Newfoundland), Estonia, Latvia, Norway, Sweden, the Russian Federation (Leningrad OblastA.V. Krylov (2003).New data on trilobites from Hecker mud mounds (Ordovician) in the Leningrad region (in Russian). ''Vestnik Sankt-Petersburgskogo Universiteta, Seriya Geologiya i Geografiya'' 3(33):95-96) and the United States (Oklahoma, Virginia). Distribution * ''L. carinatus'' is found in the Upper Ordovician of the United States (Lower Member and Botetourt limestone Member, of the Edinburgh Formation, Shenan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globampyx
''Globampyx'' is an extinct genus raphiophorid trilobites. It lived during the later part of the Arenig stage of the Ordovician Period, approximately 478 to 471 million years ago. Species of the genus are known from Canada (southeastern British Columbia), Norway (Svalbard) and Sweden. Distribution * ''G. sinalae'' is known from the Middle Ordovician of Canada (''Orthidiella'' brachiopod zone, Glenogle Shales Formation, North White River Section, British Columbia, 471.8-468.1 Ma) * ''G. trinucleoides'' is known from the Middle Ordovician of Svalbard (''Psephosthenaspis microspinosa'' small shelly zone, Olenidsletta Member, Valhallfonna Formation, Ny friesland, 471.8-457.5 Ma) Description The headshield (or cephalon) of ''Globampyx'' is densely covered with very small granules. The central raised area of the cephalon (or 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 slightl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulbaspis
''Bulbaspis'' ("bulb shield") is a late Ordovician genus of asaphid trilobites of the family Raphiophoridae found primarily in upper Ordovician-aged deepwater marine strata of Kazakhstan, China, and possibly Tasmania. Species of ''Bulbaspis'' are similar to other raphiophorids such as ''Ampyx'' and '' Raphiophorus'', save that the long spine that emanates from the glabella of the latter two genera has been modified into a knob-like or bulb-like structure in ''Bulbaspis'' that developed incrementally in the animal's growth.Zhiqiang, Zhou, and Zhou Zhiyi. "Late Ordovician trilobites from the Zhusilenghaierhan area, Ejin Banner, western Inner Mongolia, China."MEMOIR-ASSOCIATION OF AUSTRALASIAN PALAEONTOLOGISTS 32 (2006): 383. The function of the bulb is currently unknown: one hypothesis suggests sexual selection may have had a role in its evolution in the genus.Knell, Robert J., and Richard A. Fortey. "Trilobite spines and beetle horns: sexual selection in the Palaeozoic?." Biolog ... [...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] |
Mendolaspis
''Mendolaspis'' is an extinct genus of trilobites. It lived during the Arenig stage of the Ordovician Period The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The ..., approximately 478 to 471 million years ago. References Raphiophoridae Asaphida genera Ordovician trilobites Fossils of Norway Fossils of Argentina {{Asaphida-stub ... [...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] |
Kongqiangheia
''Kongqiaoheia rotundata'' is an asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. ''K. rotundata'' was originally grouped with the so-called Taklamakaniinae, a paraphyletic group of tiny, dwarfed raphiophorids that lived in a deepwater environment in what is now the Tarim Basin, including '' Pseudampyxina'', ''Nanshanaspis'', and ''Taklamakania ''Taklamakania'' is a genus of asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. Like all raphiophorids it is blind, with a headshield (or cephalon) that is subsemicircular, carrying ge ...''. Like these other genera, ''K. rotundata'' has only three thoracic segments, probably due to paedomorphic dwarfism: other raphiophorid trilobites have at minimum five thoracic segments. Morphology As with other "taklamakaniids," ''K. rotundata'' had a disk-shaped body with a semi-circular cephalon, a bulbous glabellum, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnemidopyge
''Cnemidopyge'' is a genus of trilobites that lived during the Ordovician. Like all Raphiophorids it is blind, with a cephalon that is subtriangular to subsemicircular, carrying genal spines and a forward directed rapier-like spine on the central raised area (or glabella), with the front of the glabella inflated and the natural fracture lines (or sutures) of the cephalon coinciding with its margin. It may be easily distinguished from other raphiophorids by the rectangular thorax with 6 segments, where other genera have a different number of segments and segments change in width over the length of the thorax. Uniquely in this genus, the inner pleural region of the frontal segment is enlarged.Whittington, H. B. et al. (1997) Treatise on Invertebrate Paleontology. Part O, Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. Also the axis (or rhachis) and pleural fields of the pygidium The pygidium (plural pygidia) is the posterior body part or shield ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Fortey
Richard Alan Fortey FRS FRSL (born 15 February 1946 in London) is a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007. Early life and education Fortey was educated at Ealing Grammar School for Boys and King's College, Cambridge, where he read Natural Sciences specialising in geology. He received a PhD and DSc from the University of Cambridge. Career Fortey has had a long career as a palaeontologist at the Natural History Museum in London; his research interests include above all, trilobites: at the age of 14, he discovered his first trilobite, sparking a passionate interest that later became a career. He has named numerous trilobite species and still continues his research despite having retired from the Museum. He studies trilobites and graptolites, especially those from the Ordovician and their systematics, evolution and modes of life; he is also involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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