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Gerastos
''Gerastos'' is a genus of proetid trilobite in the family Proetidae that lived between the Pragian and Eifelian of the Lower-Middle Devonian, spanning approximately 21 million years. It was described by Goldfuss in 1843. Distribution ''Gerastos'' has been found in the Devonian of Belgium, Germany, the Czech Republic and Morocco. Description ''Gerastos'' has holochroal eyes situated to the side of its enlarged glabella region of the cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont Company. Baldino s .... The surface of the cephalon can be smooth or covered with pustules. Length rarely exceeds 3 cm. References Proetidae Proetida genera Devonian trilobites of Africa Devonian trilobites {{proetida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proetida
Proetida is an order of trilobite that lived from the Ordovician to the Permian. It was the last order of trilobite to go extinct, finally dying out in the Permian-Triassic extinction event. Description These typically small trilobites resemble those of the order Ptychopariida, from which the new order Proetida was separated in 1975 by Fortey and Owens. Like the order Phacopida, the proetids have exoskeletons that sometime have pits or small tubercles, especially on the glabella (middle portion of the head). Because of their resemblance to the Ptychopariida in some features, the proetids are included in the subclass Librostoma. Unlike the trilobites of the phacopid suborder Phacopina, whose eyes are schizochroal, the proetids have the more common holochroal eyes. These eyes are characterized by close packing of biconvex lenses beneath a single corneal layer that covers all of the lenses. Each lens is generally hexagonal in outline and in direct contact with the others. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proetida Genera
Proetida is an order of trilobite that lived from the Ordovician to the Permian. It was the last order of trilobite to go extinct, finally dying out in the Permian-Triassic extinction event. Description These typically small trilobites resemble those of the order Ptychopariida, from which the new order Proetida was separated in 1975 by Fortey and Owens. Like the order Phacopida, the proetids have exoskeletons that sometime have pits or small tubercles, especially on the glabella (middle portion of the head). Because of their resemblance to the Ptychopariida in some features, the proetids are included in the subclass Librostoma. Unlike the trilobites of the phacopid suborder Phacopina, whose eyes are schizochroal, the proetids have the more common holochroal eyes. These eyes are characterized by close packing of biconvex lenses beneath a single corneal layer that covers all of the lenses. Each lens is generally hexagonal in outline and in direct contact with the others. They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proetidae
Proetidae is a family of proetid trilobites. The first species appeared in the Upper Ordovician, and the last genera survived until the Middle Permian. However, if the closely related family Phillipsiidae is actually a subfamily of Proetidae, then the proetids of Proetidae survive until the end of the Permian, where the last perish during the Permian–Triassic extinction event. Genera Proetidae ostensibly contains these following genera, though many may be placed in Phillipsiidae if the latter is, indeed, a distinct family. *'' Aayemenaytcheia'' *'' Aceroproetus'' *'' Alaskalethe'' *'' Altajaspis'' *'' Anambon'' *'' Anglibole'' *'' Angustibole'' *'' Anujaspis'' *'' Appendicysta'' *'' Aprathia'' *'' Archaeocoryphe'' *'' Ascetopeltis'' *'' Astroproetus'' (syn=''Xiushuiproetus'', ''Zhejiangoproetus'') *'' Australokaskia'' *'' Bailielloides'' *'' Bapingaspis'' *'' Basidechenella'' *'' Beleckella'' *'' Belgibole'' *'' Benesovella'' *'' Bitumulina'' *'' Blodgettia'' *'' Bohemiproetu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Devonian
The Early Devonian is the first of three Epoch (geology), epochs comprising the Devonian period, corresponding to the Lower Devonian Series (stratigraphy), series. It lasted from and began with the Lochkovian Stage , which was followed by the Pragian from and then by the Emsian, which lasted until the Middle Devonian began, . During this time, the first Ammonoidea, ammonoids appeared, descending from Bactritida, bactritoid Nautiloidea, nautiloids. Ammonoids during this time period were simple and differed little from their nautiloid counterparts. These ammonoids belong to the order Agoniatitida, which in later epochs evolved to new ammonoid orders, for example Goniatite, Goniatitida and Clymeniida. This class of cephalopod molluscs would dominate the marine fauna until the beginning of the Mesozoic Era. References {{Geological history Early Devonian, Geological epochs Devonian geochronology, *01 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalon (arthropod Head)
The cephalon is the head section of an arthropod. It is a tagma, i.e., a specialized grouping of arthropod segments. The word cephalon derives from the Greek κεφαλή (kephalē), meaning "head". Insects In insects, ''head'' is a preferred term. The insect head consists of five segments, including three (the labial, maxillary and mandibular) necessary for food uptake, which are altogether known as the gnathocephalon and house the suboesophageal ganglion of the brain, as well as the antennal segment, and an ocular segment, as well as a non segmented fused section of the head where the archicerebrum is housed known as the acron. See also arthropod head problem. Chelicerates and crustaceans In chelicerates and crustaceans, the cephalothorax is derived from the fusion of the cephalon and the thorax, and is usually covered by a single unsegmented carapace. In relation with the arthropod head problem, phylogeny studies show that members of the Malacostraca class of cru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to the nasion. Etymology The term for the area is derived from the Latin , meaning 'smooth, hairless'. In medical science The skin of the glabella may be used to measure skin turgor in suspected cases of dehydration by gently pinching and lifting it. When released, the glabella of a dehydrated patient tends to remain extended ("tented"), rather than returning to its normal shape. See also * Glabellar reflex The glabellar reflex, also known as the "glabellar tap sign", is a primitive reflex elicited by repetitive tapping of the the smooth part of the forehead above the nose and between the eyebrows. Subjects respond to the first several taps by blink ... References Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holochroal Eye
Holochroal eyes are compound eyes with many tiny lenses (sometimes more than 15,000, each 30-100μm, rarely larger). They are the oldest and most common type of trilobite eye, and found in all orders of trilobite from the Cambrian to the Permian periods. Lenses (composed of calcite) covered a curved, kidney-shaped visual surface in a hexagonal close packing In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occu ... system, with a single corneal membrane covering all lenses. Unlike in schizochroal eyes, adjacent lenses were in direct contact with one another. Lens shape generally depended on cuticle thickness. The lenses of trilobites with thin cuticles were thin and biconvex, whereas those with thick cuticles had thick lenses, which in extreme cases, could be thick columns with the outer su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The Czech Republic has a hilly landscape that covers an area of with a mostly temperate continental and oceanic climate. The capital and largest city is Prague; other major cities and urban areas include Brno, Ostrava, Plzeň and Liberec. The Duchy of Bohemia was founded in the late 9th century under Great Moravia. It was formally recognized as an Imperial State of the Holy Roman Empire in 1002 and became a kingdom in 1198. Following the Battle of Mohács in 1526, the whole Crown of Bohemia was gradually integrated into the Habsburg monarchy. The Protestant Bohemian Revolt led to the Thirty Years' War. After the Battle of White Mountain, the Habsburgs consolidated their rule. With the dissolution of the Holy Empire in 1806, the Cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg August Goldfuss
Georg August Goldfuss (Goldfuß, 18 April 1782 – 2 October 1848) was a German palaeontologist, zoologist and botanist. Goldfuss was born at Thurnau near Bayreuth. He was educated at Erlangen, where he graduated PhD in 1804 and became professor of zoology in 1818. He was subsequently appointed professor of zoology and mineralogy at the University of Bonn. Aided by Count Georg zu Münster, he issued the important (1826–44), a work which was intended to illustrate the invertebrate fossils of Germany, but it was left incomplete after the sponges, corals, crinoids, echinoderms and part of the mollusca had been figured. A collection of Goldfuss' botanical specimens are housed at Bonn University. Goldfuss died in Bonn. In 1820, he coined the word ''protozoa'' to refer to single-celled organisms such as ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the southwest, and the North Sea to the northwest. It covers an area of and has a population of more than 11.5 million, making it the 22nd most densely populated country in the world and the 6th most densely populated country in Europe, with a density of . Belgium is part of an area known as the Low Countries, historically a somewhat larger region than the Benelux group of states, as it also included parts of northern France. The capital and largest city is Brussels; other major cities are Antwerp, Ghent, Charleroi, Liège, Bruges, Namur, and Leuven. Belgium is a sovereign state and a federal constitutional monarchy with a parliamentary system. Its institutional organization is complex and is structured on both regional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to the east, and the disputed territory of Western Sahara to the south. Mauritania lies to the south of Western Sahara. Morocco also claims the Spanish exclaves of Ceuta, Melilla and Peñón de Vélez de la Gomera, and several small Spanish-controlled islands off its coast. It spans an area of or , with a population of roughly 37 million. Its official and predominant religion is Islam, and the official languages are Arabic and Berber; the Moroccan dialect of Arabic and French are also widely spoken. Moroccan identity and culture is a mix of Arab, Berber, and European cultures. Its capital is Rabat, while its largest city is Casablanca. In a region inhabited since the Paleolithic Era over 300,000 years ago, the first Moroccan s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
