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Helcionellacea
The Helcionellacea is one of two taxonomic superfamilies of extinct primitive marine molluscs within the order Bellerophontida. This superfamily is thought to be the more primitive of the two superfamilies, the other being the Bellerophontacea. These molluscs are thought to be sea snails, marine gastropod mollusks, rather than monoplacophorans. Diagnosis Helcionellaceans are characterised by cap-shaped to bellerophontiform shells; commonly with strong rugae, (transverse plications) clearly defined on both the interior and exterior of the shell; with a septum or septa partitioning off the apex, but lacking the anal emargination that is characteristic of the Bellerophontacea. Taxonomy The Helcionellacea includes two families according to the Treatise, 1960, the Helcionellidae, which is the more primitive, and the Coreospiridae, which is the more derived. The Helconellidae (Wenz, 1938) represented by the genus '' Helcionella'' (Grabau & Shimer, 1909) more closely resembles the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellerophontida
The Bellerophontida is a taxonomic order of extinct marine mollusks that are found in the fossil record from the Lower Cambrian to the Lower Triassic. They are considered by some experts to be primitive sea snails with primarily symmetrically coiled shells, marine gastropod mollusks. R.C Moore and J. Brooks Knight ''et al'' 1960 Treatise on Invertebrate Paleontology, Part I Mollusca 1 recognized bellerophonts as true gastropods, placing them as the suborder Bellerophontina in the subclass Prosobranchia, order Archaeogastropoda. Some more recent workers in the field have expressed uncertainty as to the taxonomic placement of this group. Shell morphology Shells of bellerophontids are most commonly isotrophic (coiled symmetrically), rarely slightly asymmetric. Most are closely coiled with some general more openly coiled, cyrtiform; predominantly with a median slit in the upper lip of the aperture, or with a series of openings known as tremata, usually generating a selenizone whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm August Wenz
Wilhelm August Wenz (21 October 1886 – 12 September 1945) was a German malacologist, born in Frankfurt am Main. He is the author of the 7-part Gastropoda section of ''Handbuch der Paläozoologie'' (1938-1944), a very important review that described all known fossil genera. Only a few copies of this rare work survive: almost the entire stock of later editions was destroyed during the Second World War. Bibliography (incomplete) * Fischer K. & Wenz W. A. (1914''Die Landschneckenkalke des Mainzer Beckens und ihre Fauna'' * Wenz W. (1923-1930) "Gastropoda extramarina tertiaria" ''Fossilium catalogus, I: Animalia''. 3387 pp., published in parts. * Wenz W. (1938-1944) ''Teil 1: Allgemeiner Teil und Prosobranchia Prosobranchia was a large taxonomic subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyletic (consisting of more than one lineage of descent). Gen ...''. In: Schindewo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latouchella
''Latouchella'' is an extinct genus of marine invertebrate animal, that is considered to be a mollusk and which may be a sea snail, a gastropod. It is a helcionellid from the Tommotian epoch of what is now Siberia. Its tightly coiled, spiral shell contains a number of low "walls" running up the front surface of the interior; these would have directed water currents within its shell. Between these walls are a series of furrows, parallel to the shell's aperture, giving casts of the internal structure the appearance of a railway line, with sleepers (created by furrows) tying together paired rails that run towards the apex of the shell. Description This genus had a curved, segmented shell, and it is often reconstructed as a snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Gastropods
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), 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 Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, Intern ... [...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] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically been home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone during th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igarkiellidae
''Igarkiella'' is an extinct genus of trilobite containing a single described species ''Igarkiella igarkaensis''. The species is known from fossils dating to 505 to 501 million years ago during the Cambrian Period The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million .... The fossils were described from an outcrop of the Labaz Formations Saami Member along the Kulyumbe River in Krasnoyar, Russia. References Cambrian trilobites Anomocaridae {{asaphida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
