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Helcionopsis Radiatum
''Helcionopsis radiatum'' is an extinct species of paleozoic monoplacophoran in the family Tryblidiidae. This species was first named as ''Tryblidium radiatum'' and described from Silurian in crystalline limestone of Wialmsudd near Fårösund in Sweden by Gustaf Lindström Gustaf Lindström (27 August 1829 – 16 May 1901) was a Sweden, Swedish paleontologist. He was born in Visby on Gotland. In 1848 he entered Uppsala University, and in 1854 he took his doctor's degree. Having attended a course of lectures in ... in 1884. Lindsröm found only one specimen. Shell description The shell is oval and much elevatedly conical. The greatest height is lying near the middle of the longitudinal axis. The apex is in anterior end, truncated, curved as to lean forwards over the anterior margin of the aperture. The shell between the apex and the margin is consequently much concave. The apertural border is straight and horizontal. The surface is covered by fine, closely packed, radia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustaf Lindström
Gustaf Lindström (27 August 1829 – 16 May 1901) was a Sweden, Swedish paleontologist. He was born in Visby on Gotland. In 1848 he entered Uppsala University, and in 1854 he took his doctor's degree. Having attended a course of lectures in Stockholm by Sven Lovén, he became interested in the zoology of the Baltic Sea, Baltic, and published several papers on the invertebrate fauna (animals), fauna, and subsequently on the fishes. In 1856 he became a school teacher, and in 1858 a master in the grammar school at Visby. His leisure was devoted to researches on the fossils of the Silurian rocks of Gotland, including the corals, brachiopods, gastropods including pteropods, cephalopods and Crustacea. He described also remains of the fish ''Cyathaspis'' from Wenlock Beds in Gotland, with Tamerlan Thorell, a scorpion ''Palaeaphonus'' from Ludlow Beds at Wisby. He determined the true nature of the operculated coral. He was awarded the Murchison Medal by the Geological Society of Lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the fossil record, and were thought to have become extinct 375 million years ago. Although the shell of many monoplacophorans is limpet-like in shape, they are not gastropods, nor do they have any close relation to gastropods. Definition Discussion about monoplacophorans is made difficult by the slippery definition of the taxon; some authors take it to refer to all non-gastropod mollusks with a single shell, or all single-shelled mollusks with serially repeated units; whereas other workers restrict the definition to cap-shaped forms, excluding spiral and other shapes of shell. The inclusion of the gastropod-like Bellerophontoidea within the group is also contentious. One attempt to resolve this confusion was to separate out the predom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tryblidiidae
Tryblidiidae is an extinct family of paleozoic monoplacophorans in the superfamily Tryblidioidea. Genera Genera in the family Tryblidiidae include: * ''Tryblidium'' Gustaf Lindström, Lindström, 1880. From Ordovician and Silurian.W. H. Dall, Dall W. H. 1913. ''Gastropods''. In: Charles Rochester Eastman, Eastman C. R. ''Text Book of Paleontology edited by C. R. Eastman adapted from German of K. A. von Zittel, 2nd edition revised and enlarged by the editor in collaboration with the following named specialists: R.S. Bassler, W. H. Dall, Charles Doolittle Walcott, C. D. Walcott.'Volume 1 MacMillan & Co., London. xii + 839 ppPage 521 * ''Drahomira'' Perner, 1903 ** ''Drahomira barrandei'' ** ''Drahomira glaseri'' ** ''Drahomira kriziana'' ** ''Drahomira rugata'' * ''Helcionopsis'' Ulrich & Scofield, 1897 * ''Pentalina (mollusc), Pentalina'' Horný, 1961 ** ''Pentalina prantli'' Horný, 1961 * ''Pilina'' References Prehistoric monoplacophorans Prehistoric mollusc families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fårösund
Fårösund is a locality situated on the Swedish island of Gotland with 800 inhabitants in 2014. The village can be reached by car from Visby. The island of Fårö can be reached by ferry from Fårösund. Fårösund is the northernmost town in the municipality of Gotland in Gotland County, about north of Visby. Fårösund is situated on the seafront overlooking the island of Fårö and is visited by tourists during the summer, but it is usually a quiet community in the autumn, winter and spring. Until the mid-1900s it was a small quiet resort as well as a ferry terminal for ferries to Fårö. As of February 2017 the Swedish Government is attempting to buy back the former naval port and related facilities, in the face of opposition from private interests including a Russian oligarch, as part of the emergency remilitarization of Gotland in the second half of the 2010s. Fårösund is also the name of the strait between Gotland's "mainland" and Fårö. Climate Fårösund has a mari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc Shell
The mollusc (or molluskOften spelled mollusk shell in the USA; the spelling "mollusc" are preferred by ) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although these te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apex (mollusc)
In anatomy, an apex (adjectival form: apical) is part of the shell of a mollusk. The apex is the pointed tip (the oldest part) of the shell of a gastropod, scaphopod, or cephalopod. The apex is used in end-blown conches. Gastropods The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod. The apex is the first-formed, and therefore the oldest, part of the shell. To be more precise, the apex would usually be where the tip of the embryonic shell or protoconch is situated, if that is still present in the adult shell (often it is lost or eroded away). Coiled gastropod shells The phrase apical whorls, or protoconch, means the whorls that constitute the embryonic shell at the apex of the shell, especially when this is clearly distinguishable from the later whorls of the shell, otherwise known as the teleoconch. Comparison of the apical part and the whole shell of ''Otukaia kiheiziebisu'': File:Calliostoma kiheiziebisu apex.png File:Calliostoma k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Monoplacophorans
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] |
