|
Strabops
''Strabops'' is a genus of strabopid, an extinct group of arthropods. ''Strabops'' is known from a single specimen from the Late Cambrian (Furongian age) of the Potosi Dolomite, Missouri, collected by a former professor, Arthur Thacher. It is classified in the family Strabopidae of the monotypic order Strabopida, a group closely related to the aglaspidids with uncertain affinities. The generic name is composed by the Ancient Greek words στραβός, meaning "squinting", and ὄψῐς, meaning "face" (and therefore, "squinting face"). The history of ''Strabops'' has been turbulent and confusing since its original description by Charles Emerson Beecher, who classified it as a eurypterid. Many authors do not agree with this and have classified ''Strabops'' and its allies as part of the Aglaspidida order, while others classify them in their own order. Although the latter is the taxonomic position currently accepted, other paleontologists prefer to simply omit the strabopids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabops Thacheri Restoration
''Strabops'' is a genus of strabopid, an extinct group of arthropods. ''Strabops'' is known from a single specimen from the Late Cambrian (Furongian age) of the Potosi Dolomite, Missouri, collected by a former professor, Arthur Thacher. It is classified in the family Strabopidae of the monotypic order Strabopida, a group closely related to the aglaspidids with uncertain affinities. The generic name is composed by the Ancient Greek words στραβός, meaning "squinting", and ὄψῐς, meaning "face" (and therefore, "squinting face"). The history of ''Strabops'' has been turbulent and confusing since its original description by Charles Emerson Beecher, who classified it as a eurypterid. Many authors do not agree with this and have classified ''Strabops'' and its allies as part of the Aglaspidida order, while others classify them in their own order. Although the latter is the taxonomic position currently accepted, other paleontologists prefer to simply omit the strabopids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleomerus
''Paleomerus'' is a genus of strabopid, a group of extinct arthropods. It has been found in deposits from the Cambrian period (Atdabanian epoch). It is classified in the family Strabopidae of the monotypic order Strabopida. It contains two species, ''P. hamiltoni'' from Sweden and ''P. makowskii'' from Poland. The generic name is composed by the Ancient Greek words παλαιός (''palaiós''), meaning "ancient", and μέρος (''méros''), meaning "part" (and therefore, "ancient part"). ''Paleomerus'' is one of the oldest arthropods, being sometimes interpreted as the model of the first arachnomorphs. It is part of the order Strabopida, a poorly known group closely related to the aglaspidids of uncertain affinities, often being ignored by researchers and authors due to the poor preservation and abundance of their fossils. It has been suggested that ''Paleomerus'' and the closely related '' Strabops'' could be synonymous with each other, since they differ only in the si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabopidae
Strabopidae is the only family of the order Strabopida, a group of arachnomorph arthropods. The order Strabopida contains three valid genera and one doubtful, '' Khankaspis'', ''Paleomerus'', ''Parapaleomerus'' and ''Strabops'', all assigned in the family Strabopidae. Previously, it also contained the genera '' Caryon'', ''Lemoneites'' and '' Neostrabops'', but after a study, they were reassigned as a trilobite, a glyptocystitid echinoderm and a cheloniellid arthropod, respectively. Paleomeridae was also previously included as a family, but after the discovery of a fourth ''Paleomerus'' specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository f ... and its study, Paleomeridae was synonymized into Strabopidae. References Strabopida Prehistoric arthropod families Controversial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabopid
Strabopidae is the only family of the order Strabopida, a group of arachnomorph arthropods. The order Strabopida contains three valid genera and one doubtful, '' Khankaspis'', ''Paleomerus'', ''Parapaleomerus'' and ''Strabops'', all assigned in the family Strabopidae. Previously, it also contained the genera '' Caryon'', ''Lemoneites'' and '' Neostrabops'', but after a study, they were reassigned as a trilobite, a glyptocystitid echinoderm and a cheloniellid arthropod, respectively. Paleomeridae was also previously included as a family, but after the discovery of a fourth ''Paleomerus'' specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository f ... and its study, Paleomeridae was synonymized into Strabopidae. References Strabopida Prehistoric arthropod families Controversial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterid
Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus '' Eurypterus'' accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Triassic extinction event (or some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aglaspidid
Aglaspidida is an extinct order of aquatic arthropods that were once regarded as primitive chelicerates. However, anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within the chelicerates, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites. Aglaspidida contains the subgroups Aglaspididae and Tremaglaspididae, which are distinguished by the presence of acute/spinose genal angles and a long spiniform tailspine in the Aglaspididae. Aglaspidid fossils are found in North America (upper Mississippi valley, Missouri and Utah), Europe, Australia, and China. Certain other artiopods are believed to be closely related to the aglaspidids, including the order Strabopida, which includes the genera '' Strabops'', ''Paleomerus ''Paleomerus'' is a genus of strabopid, a group of extinct arthropods. It has been found in deposits from the Cambrian period (Atdabanian epoch). It is classified in the family Strabopidae of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potosi Dolomite
The Potosi Formation is a geologic formation in Missouri, Illinois and Indiana. It preserves fossils dating back to the Cambrian period. Paleofauna Monoplacophora Monoplacophora , meaning "bearing one plate", is a polyphyletic superclass of molluscs with a cap-like shell inhabiting deep sea environments . Extant representatives were not recognized as such until 1952; previously they were known only from ... * '' Gayneoconus'' : ''G. echolsi'' See also * List of fossiliferous stratigraphic units in Missouri * Paleontology in Missouri References * Cambrian Missouri Dolomite formations Geography of St. Francois County, Missouri Cambrian System of North America Geologic formations of Missouri Cambrian southern paleotropical deposits {{Missouri-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on account of not arising in the embryo from teloblast areas as other segments. It never carries any appendages, but a forked "tail" called the caudal furca may be present. The shape and composition of the telson differs between arthropod groups. Crustaceans In lobsters, shrimp and other decapods, the telson, along with the uropods, forms the tail fan. This is used as a paddle in the caridoid escape reaction ("lobstering"), whereby an alarmed animal rapidly flexes its tail, causing it to dart backwards. Krill can reach speeds of over 60 cm per second by this means. The trigger time to optical stimulus is, in spite of the low temperatures, only 55 milliseconds. In the Isopoda and Tanaidacea (superorder Peracarida), the last abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Eyes
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light. Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point. The individual light receptors behind each lens are then turned on and off due to a series of changes in the light intensity during movement or when an object in moving, creating a flick ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalocarid
Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the last two originally refer to the family Anomalocarididae, which previously included all species of this order but is now restricted to only a few species. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts included the earliest large predators known, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa '' Anomalocaris canadensis'', '' Hurdia victoria'', ''Peytoia nathorsti'', '' Titanokorys gainessii, Cambroraster falcatus'' and '' Amplectobelua symbrachiata'', the Ordovician '' Aegirocassis benmoulai'' and the Devonian '' Schinderhannes bartelsi''. Etymology The name Radiodon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Science
The ''American Journal of Science'' (''AJS'') is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself. Until 1880, it was also known as the ''American Journal of Science and Arts'', but its focus was always on natural sciences and especially on geology and related subjects. In early years, the journal was often referred to as "Silliman's Journal", and the publication became associated with Yale University due to his long tenure there (1804–1853). The editorship long remained in the family of Professor Silliman, as he was assisted by his son, Benjamin Silliman Jr., from 1838. On the death of the elder Silliman in 1864, he was succeeded as chief editor by his son-in-law, James Dwight Dana, and then from 1895 till 1926 by Dana's son Edward Salisbury Dana. Associate editors included the botanist Asa Gray and the zoologist Louis Agassiz. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
