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Pseudotriakidae
The Pseudotriakidae are a small family of ground sharks, belonging to the order Carcharhiniformes, containing the false catsharks (genera '' Pseudotriakis'' and ''Planonasus'') and gollumsharks (genus ''Gollum''). It contains the only ground shark species that exhibit intrauterine oophagy, in which developing fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...es are nourished by eggs produced by their mother. Genera The Pseudotriakidae contains the following genera: Undescribed species One undescribed species is known - one in the genus ''Gollum'', (''Gollum'' sp. B) - the white-marked gollumshark.Weigmann, S., Stehmann, M.F.W. & Thiel, R. (2013): ''Planonasus parini'' n. g. and n. sp., a new genus and species of false cat sharks (Carchariniformes, Pseudotriakidae) from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
False Catshark
The false catshark or sofa shark (''Pseudotriakis microdon'') is a species of ground shark in the family Pseudotriakidae, and the sole member of its genus. It has a worldwide distribution, and has most commonly been recorded close to the bottom over continental and insular slopes, at depths of . Reaching in length, this heavy-bodied shark can be readily identified by its elongated, keel-like first dorsal fin. It has long, narrow eyes and a large mouth filled with numerous tiny teeth. It is usually dark brown in color, though a few are light gray. With flabby muscles and a large oily liver, the false catshark is a slow-moving predator and scavenger of a variety of fishes and invertebrates. It has a viviparous mode of reproduction, featuring an unusual form of oophagy in which the developing embryos consume ova or egg fragments released by the mother and use the yolk material to replenish their external yolk sacs for later use. This species typically gives birth to two pups at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slender Smooth-hound
The slender smooth-hound or gollumshark (''Gollum attenuatus'') is a species of ground shark in the family Pseudotriakidae. It is endemic to the waters around New Zealand, where it is usually found close to the bottom over the continental slope at depths of . An extremely slim, plain brownish shark reaching in length, the slender smooth-hound can be identified by its broad, flattened head with a long, distinctively bell-shaped snout. Its mouth is angular with short furrows at the corners, and contains a very high number of tooth rows in both jaws. Its two dorsal fins are roughly equal in size. The diet of the slender smooth-hound is diverse, but dominated by small, benthic bony fishes and decapod crustaceans. It exhibits a specialized form of aplacental viviparity with oophagy: the females produce a single capsule in each uterus that contains 30–80 ova, of which one ovum develops into an embryo that consumes the rest of the ova and stores the yolk material in its external ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudotriakis
The false catshark or sofa shark (''Pseudotriakis microdon'') is a species of ground shark in the family Pseudotriakidae, and the sole member of its genus. It has a worldwide distribution, and has most commonly been recorded close to the bottom over continental and insular slopes, at depths of . Reaching in length, this heavy-bodied shark can be readily identified by its elongated, keel-like first dorsal fin. It has long, narrow eyes and a large mouth filled with numerous tiny teeth. It is usually dark brown in color, though a few are light gray. With flabby muscles and a large oily liver, the false catshark is a slow-moving predator and scavenger of a variety of fishes and invertebrates. It has a viviparous mode of reproduction, featuring an unusual form of oophagy in which the developing embryos consume ova or egg fragments released by the mother and use the yolk material to replenish their external yolk sacs for later use. This species typically gives birth to two pups at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharhiniformes
Carcharhiniformes ( from Classical Greek ' (karcharos) 'sharp/jagged' and ' (rhinos) 'nose', plus Latin ''forme'' 'shape'), commonly known as ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and requiem sharks. Members of this order are characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin, and five gill slits. The families in the order Carcharhiniformes are expected to be revised; recent DNA studies show that some of the conventional groups are not monophyletic. The oldest members of the order appeared during the Middle-Late Jurassic, which have teeth and body forms that are morphologically similar to living catsharks. Carchariniformes first underwent major diversification during the Late Cretaceous, initially as mostly small-sized forms, before radiating into medium and large body sizes during the Cenozoic. Families Eschmeyer's Catalog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planonasus
''Planonasus'' is a genus of ground sharks in the family Pseudotriakidae, native to the western Indian Ocean. Species There are currently two species in this genus: * ''Planonasus parini'' (Simon Weigmann, Weigmann, Matthias Stehmann, Stehmann & Ralf Thiel, Thiel, 2013) (dwarf false catshark) * ''Planonasus indicus'' (David A. Ebert, Ebert, K. V. Akhilesh, Akhilesh, & Weigmann, 2018) (pygmy false catshark) References Planonasus, Shark genera {{Shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gollum (shark)
''Gollum'' is a genus of ground sharks in the family Pseudotriakidae, native to the southwestern Pacific Ocean. The genus was described in 1973 by biologist Leonard Compagno, who named it named after the character Gollum from J. R. R. Tolkien's works, noting the species ''Gollum attenuatus'' (the slender smooth-hound) "bears some resemblance in form and habits". Species The currently described species and one undescribed species in this genus are: * '' Gollum attenuatus'' ( Garrick, 1954) (slender smooth-hound) * '' Gollum suluensis'' Last A last is a mechanical form shaped like a human foot. It is used by shoemakers and cordwainers in the manufacture and repair of shoes. Lasts come in many styles and sizes, depending on the exact job they are designed for. Common variations ... & Gaudiano, 2011 (Sulu gollumshark) * ''Gollum'' sp. B not yet described (white-marked gollumshark) See also * '' Aenigmachanna gollum'', a species of fish named after the same character fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oophagy
Oophagy ( ) or ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, "to eat"). In contrast, adelphophagy is the cannibalism of a multi-celled embryo. Oophagy is thought to occur in all sharks in the order Lamniformes and has been recorded in the bigeye thresher (''Alopias superciliosus''), the pelagic thresher (''A. pelagicus''), the shortfin mako (''Isurus oxyrinchus'') and the porbeagle (''Lamna nasus'') among others. It also occurs in the tawny nurse shark (''Nebrius ferrugineus''), and in the family Pseudotriakidae. This practice may lead to larger embryos or prepare the embryo for a predatory lifestyle. There are variations in the extent of oophagy among the different shark species. The grey nurse shark (''Carcharias taurus'') practices intrauterine cannibalism, the first developed embryo consum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodore Gill
Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist, and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural history. He was associated with J. Carson Brevoort in the arrangement of the latter's entomological and ichthyological collections before going to Washington, DC, in 1863 to work at the Smithsonian Institution. He catalogued mammals, fishes, and mollusks most particularly, although he maintained proficiency in other orders of animals. He was librarian at the Smithsonian and also senior assistant to the Library of Congress. He was elected as a member of the American Philosophical Society in 1867. Gill was professor of zoology at George Washington University. He was also a member of the Megatherium Club at the Smithsonian Institution in Washington, DC. Fellow members frequently mocked him for his vanity. He was president of the American Asso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fetus
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Prenatal development is a continuum, with no clear defining feature distinguishing an embryo from a fetus. However, in general a fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional, and some may not yet be situated in their final Anatomy, anatomical location. In human prenatal development, fetal development begins from the ninth week after Human fertilization, fertilization (which is the eleventh week of Gestational age (obstetrics), gestational age) and continues until the childbirth, birth of a newborn. Etymology The word ''wikt:fetus#English, fetus'' (plural ''wikt:fetuses#English, fetuses'' or rarely, the solecism ''wikt:feti#English, feti''''Oxford English Dict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonard Compagno
Leonard Joseph Victor Compagno (1943-2024) was an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization (FAO) of the United Nations. Compagno was mentioned in the credits of the 1975 film '' Jaws'' along with the National Geographic Society. Career *Ph.D, Stanford University, 1979 *Adjunct professor, San Francisco State University, 1979 to 1985 *Curator of Fishes in the Division of Life Sciences and Head of the Shark Research Centre (SRC), Iziko Museums, Cape Town *Director, Shark Research Institute (SRI) Selected bibliography *Compagno, L.J.V., 1979. ''Carcharhinoid sharks: morphology, systematics and phylogeny''. Unpublished Ph. D. Thesis, Stanford University, 932 p. Available from University Microfilms International, Ann Arbor, Michigan. *Leonard Compagno, 1984a. FAO The Food and Agriculture Organization o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
