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Selenizone
A selenizone (from the Greek "selene" meaning "moon", and "zone" meaning "girdle") is an anatomical structure that exists in the shells of some families of living sea snails: the slit shells, the little slit shells and the abalones, which are marine gastropod mollusks from ancient lineages. It is a spiral band of crescentric growth lines or threads (lunulae) on the shell surface due to the semicircular end of a notch or slit on the outer lip. A structure of the same type exists in several fossil groups of mollusks, including all the fossil families of slit shells, as well as three superfamilies of what may have been gastropods, but may possibly have been monoplacophorans or paragastropods instead. The function of the holes and slits in living sea snails is to allow for exhalant water circulation, which is important for respiration and other functions. It has also been suggested that the selenizone may serve to reinforce the shell against catastrophic breakage during pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mikadotrochus Hirasei 01
''Mikadotrochus'' is a genus of sea snails, marine gastropod mollusks in the family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ... Pleurotomariidae, the slit snails. Species Species within the genus ''Mikadotrochus'' include: * '' Mikadotrochus beyrichii'' ( Hilgendorf, 1877) * '' Mikadotrochus gotoi'' (Anseeuw, 1990) * '' Mikadotrochus hirasei hirasei'' ( Pilsbry, 1903) ** '' Mikadotrochus hirasei yamamotoi'' (A. Yamamoto, 1993), Species inquirenda * '' Mikadotrochus mikadotrochus'' Pilsbry * '' Mikadotrochus salmianus'' (Rolle, 1887) * ''Mikadotrochus nantoensis''Lin，1975: ;Species brought into synonymy : * ''Mikadotrochus amabilis'' Bayer, 1963: synonym of '' Perotrochus amabilis'' (Bayer, 1963) * ''Mikadotrochus anseeuwi'' Kanazawa & Y. Goto, 1991: synonym of '' Perot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suture (anatomy)
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements. Sutures are found in the skeletons or exoskeletons of a wide range of animals, in both invertebrates and vertebrates. Sutures are found in animals with hard parts from the Cambrian period to the present day. Sutures were and are formed by several different methods, and they exist between hard parts that are made from several different materials. Vertebrate skeletons The skeletons of vertebrate animals (fish, amphibians, reptiles, birds, and mammals) are made of bone, in which the main rigid ingredient is calcium phosphate. Cranial sutures The skulls of most vertebrates consist of sets of bony plates held together by cranial sutures. These sutures are held together mainly by Sharpey's fibers which grow from each bone into the adjoining one. Sutures in the ankles of land vertebrates In the type of crurotarsal ankle which is fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurotomarioidea
Pleurotomarioidea is a superfamily of small to large marine gastropods included in the order Pleurotomariida of the subclass Vetigastropoda. These are the slit shells, originally named Pleurotomariacea, in keeping with the convention for naming superfamilies at the time. This updated version of the name for the taxon is usually used by students of the living Mollusca. Paleontologists often still use the name Pleurotomariacea instead. Evolutionary history Forming the first evidence of crown-group gastropods when they appeared in the Upper Cambrian, the fossil record of the Pleurotomarioideans has no substantial gaps until today. The group took quite a hit at the Cretaceous–Paleogene boundary (K–T boundary), with only the Pleurotomariidae surviving the Cretaceous–Paleogene extinction event – and then only in deep waters. Living representatives of the group were first discovered in the mid-19th century, and their unusual mix of primitive and derived characters per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haliotoidea
Haliotoidea is a superfamily of sea snails, marine gastropod mollusks in the subclass Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . ISSN 0076-2997. 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278MolluscaBase eds. (2022). MolluscaBase. Haliotoidea Rafinesque, 1815. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=156488 on 2022-06-04 Families The superfamily Haliotoidea contains (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005) two families: * The recent family Haliotidae, also known as abalone Abalone ( or ; via Spanish , from Rumsen ''aulón'') is a common name for any of a group of small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Taxon
Neontology is a part of biology that, in contrast to paleontology, deals with living (or, more generally, '' recent'') organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example: * The moose (''Alces alces'') is an extant species, and the dodo (''Raphus cucullatus'') is an extinct species. * In the group of molluscs known as the cephalopods, there were approximately 600 extant species and 7,500 extinct species. A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of living species ("Lazarus species"), or if previously-known extant species are reclassified as members of the taxon. Most biologists, zoologists, and botanists are in practice neontologists, and the term neontologist is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Untorted
Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod. This rotation brings the mantle cavity and the anus to an anterior position above the head. In some groups of gastropods ( Opisthobranchia) there is a degree of secondary detorsion or rotation towards the original position; this may be only partial detorsion or full detorsion. The torsion or twisting of the visceral mass of larval gastropods is not the same thing as the spiral coiling of the shell, which is also present in many shelled gastropods. Development There are two different developmental stages which cause torsion. The first stage is caused by the development of the asymmetrical velar/foot muscle which has one end attached to the left side of the shell and the other end has fibres attached to the left side of the foot and head. At a certain point in la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeogastropods
Archaeogastropoda (also known as Aspidobranchia) was a taxonomic order of sea snails used in older classifications of gastropods, i.e. snails and slugs. Archeogastropoda are marine prosobranch gastropod mollusks, mainly herbivores, typically having two gills and a double-chambered heart, with the eggs and sperm discharged directly into the water. They were traditionally regarded as a relatively primitive group. This older classification of the gastropods is based on the classification of Johannes Thiele (1925). This classification was not based on true phylogenetic relationships, but on more general affinities between the groups. In the last few years, two new cladistic taxonomies of the gastropods have been published (in 1997 and 2005). This has led to an extensive reclassification of gastropod taxa. The taxon Archaeogastropoda was found to be a paraphyletic group, and therefore unacceptable in a strictly cladistic classification. In the 1997 classification, most of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macluritoidea
The Macluritoidea, or Macluritacea as it was originally spelled, is a superfamily of hyperstrophically coiled, Upper Cambrian to Devonian, archaeogastropods,Treatise on Invertebrate Paleontology, Part I, Mollusca 1. R.C. Moore (ed); Geol Soc of America and Univ Kansas Press, 1960 or paragastropods according to Linsely and Kier (1984).Robert M. Linsely, & Willian M. Kier, 1984. The Paragastropoda: a proposal for a new class of Paleozoic Mollusca. Malacologia, v.25, no.1, pp 241-254 Coiling is dextral, although it appears sinistral, deduced from the position of the channel (presumed to be exhalent) contained in a ridge or keel (a selenizone on what is assumed to be the upper side. This is supported by the operculum of '' Maclurites'', which corresponds to that of dextral gastropods. According to the Treatise the Macluritaceae includes two families, the Onychochilidae and Macluridae. Subsequent placement in the Paragastropoda is based on the assumption these animals were untort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euomphaloidea
Euomphaloidea, originally Euomphalacea, is an extinct superfamily of marine molluscs that lived from the Early Ordovician to the Late Cretaceous, included in the Gastropoda Moore R. C., Lalicker & Fischer (1952). ''Invertebrate Fossils''. McGraw-Hill publisher. but speculated as instead perhaps Monoplacophora. Description Euomphaloid shells are mostly discoidal and may be either orthostrophic (coils wrapped around an erect cone) or hyperstrophic (coils wrapped around an inverted cone); are widely umbilicate and commonly have a channel, presumed exhalent, within the angulation in the outer part of the upper whorl surface. The shell wall is relatively thick, with an external prismatic layer of calcite, which may be pigmented, and an internal layer of lamellar, but not nacreous, aragonite.(1960). ''Treatise on Invertebrate Paleontology. Part I, Gastropoda. Taxonomy As with almost all fossils, the taxonomic relations of and within the euophaloids can only be inferred from their r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellerophontoidea
Bellerophontoidea, common name "bellerophonts",Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . ISSN 0076-2997. 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278 is a Taxonomic rank, superfamily of extinct planospirally-coiled globose molluscs. This superfamily is generally included within the Gastropoda, but may instead be a group of monoplacophorans. The taxon first appeared late in the Cambrian and continued until late in the Triassic. Biology Unlike normal gastropods, the shells of Bellerophonts are characterised by a completely planispiral pattern of coiling, such as one finds in shelled cephalopods. Experts disagree whether Bellerophontids should be classified as Torsion (gastropod), torted gastropods, or as untorted Tergomya, or whether the group Bellerophontida is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haliotidae
''Haliotis'', common name abalone, is the only genus in the family Haliotidae. This genus once contained six subgenera. These subgenera have become alternate representations of ''Haliotis''. The genus consists of small to very large, edible, herbivorous sea snails, marine gastropod molluscs. The number of species recognized worldwide ranges between 30 and 130, with over 230 species-level taxa described. The most comprehensive treatment of the family considers 56 species valid, with 18 additional subspecies. Other common names are ear shells, sea ears, and, rarely, muttonfish or muttonshells in parts of Australia, ormer in the UK, perlemoen in South Africa, and the Maori name for three species in New Zealand is pāua. Description The shells of abalones have a low, open, spiral structure, and are characterized by having several open respiratory pores in a row near the shell's outer edge. The thick inner layer of the shell is composed of nacre, which in many species of ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
