|
Hemigaleidae
The weasel sharks are a family, the Hemigaleidae, of ground sharks found from the eastern Atlantic Ocean to the continental Indo-Pacific. They are found in shallow coastal waters to a depth of . Most species are small, reaching no more than long, though the snaggletooth shark (''Hemipristis elongatus'') may reach . They have horizontally oval eyes, small spiracles, and precaudal pits. Two dorsal fins occur with the base of the first placed well forward of the pelvic fins. The caudal fin has a strong ventral lobe and undulations on the dorsal lobe margin. They feed on a variety of small bony fishes and invertebrates; at least two species specialize on cephalopods. They are not known to have attacked people. Genera and species The eight known species in this family are placed in four genera. ''Hemipristis'' is placed in the subfamily Hemipristinae, while ''Chaenogaleus'', ''Hemigaleus'', and ''Paragaleus'' are placed in the subfamily Hemigaleinae.Haaramo, M. (2005)Hemigalei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharhiniformes
Carcharhiniformes , the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark. 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 bodyforms that are morphologically similar to living catsharks. Carchariniformes first underwent major diversification during the Late Cretaceous, initially as small-sized forms, before radiating into medium and large body sizes during the Cenozoic. Families According to FishBase, the nine families of ground sharks are: [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Weasel Shark
The Australian weasel shark (''Hemigaleus australiensis'') is an uncommon species of ground shark in the family Hemigaleidae. It inhabits shallow waters off northern Australia to a depth of ; smaller sharks frequent sand and seagrass habitat and shift to coral reefs as they grow older. A slim, drab species reaching a length of , it has sickle-shaped fins with dark tips on the second dorsal fin and caudal fin upper lobe. Its upper teeth are broad with strong serrations only on the trailing edge. The lateral line along each side is prominent and exhibits a downward curve below the second dorsal fin. Feeding almost exclusively on octopuses and other cephalopods, the Australian weasel shark mostly hunts near the sea floor. It is viviparous, with the developing embryos nourished through a placental connection and born after a six-month gestation period. This species is productive for a shark, with females bearing litters of 1–19 pups usually twice per year. The Australian wea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemipristis Curvatus
''Hemipristis curvatus'' is an extinct species of weasel shark which existed during the Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ... epoch. It was described by Dames in 1883. References Hemipristis Eocene sharks Fossils of Poland Fossils of Mexico Fish described in 1879 {{Shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sicklefin Weasel Shark
The sicklefin weasel shark (''Hemigaleus microstoma'') is an uncommon species of ground shark in the family Hemigaleidae. It is native to southern India, southern China, and parts of Southeast Asia, living in shallow waters down to a depth of . This lightly built shark is characterized by its very short mouth, broad upper teeth with serrations only on the trailing edge, and strongly sickle-shaped fins with obvious white tips on the two dorsal fins. It is light grey or bronze in colour, often with small white blotches on its sides; it reaches a maximum known length of . Spending most of its time close to the sea floor, the sicklefin weasel shark is a specialist predator of cephalopods. Its reproductive mode is viviparous, in which the unborn young form a placental connection to their mother. Females probably give birth twice a year, with each litter consisting of two to four pups. The sicklefin weasel shark is widely caught by artisanal fisheries and used for meat, fins, and fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snaggletooth Shark
The snaggletooth shark, or fossil shark (''Hemipristis elongata''), is a species of weasel shark in the family Hemigaleidae, and the only extant member of the genus ''Hemipristis''. It is found in the Indo-West Pacific, including the Red Sea, from southeast Africa to the Philippines, north to China, and south to Australia, at depths from 1 to 130 metres. This shark can be found near the bottom of the water column of coastal areas, but can be found at continental and insular shelves. Its length is up to 240 cm (7.87 ft) . Despite being only vulnerable to extinction, this shark is very rarely seen. Anatomy The snaggletooth's coloration is light grey or bronze with no prominent markings. As its name suggests, it has sharp, serrated teeth on the upper jaw and hooked teeth on the bottom jaw. The shape of its body is fusiform, allowing it greater speed in the water. Reproduction is a special kind of viviparity, called placental viviparity, where the shark carries its live yo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hooktooth Shark
The hooktooth shark (''Chaenogaleus macrostoma''), is a weasel shark of the family Hemigaleidae, the only extant member of the genus ''Chaenogaleus'', but there is an extinct species, ''Chaenogaleus affinis''. The hooktooth shark is found in the tropical Indo-West Pacific oceans between latitudes 30° N and 10° S, including the Persian Gulf, Pakistan, India, Sri Lanka, Singapore, Thailand, Viet Nam, China, Taiwan, and Java and Sulawesi in Indonesia, from the surface to a depth of 59 meters. It can reach a length of 1 meter. It is considered a vulnerable species. See also * List of prehistoric cartilaginous fish genera References * Chaenogaleus Marine fauna of South Asia Marine fauna of Southeast Asia Aquitanian genus first appearances Extant Miocene first appearances hooktooth shark The hooktooth shark (''Chaenogaleus macrostoma''), is a weasel shark of the family Hemigaleidae, the only extant member of the genus ''Chaenogaleus'', but there is an extinct spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemipristis
''Hemipristis'' (from el, ἡμι , 'half' and el, πρίστης 'saw') is a genus of weasel sharks, family Hemigaleidae. It contains one extant species, the snaggletooth shark (''H. elongata'') and several extinct species. ''Hemipristis'' has two distinct types of teeth in each section of its jaw. The ones on the upper jaw act as knives, cutting through the flesh of the prey, while the pointed ones on the bottom act as forks, spearing the prey and holding it down. Because this shark was poorly studied in the past and its top and bottom jaw teeth differ to such a great degree, its top and lower jaw teeth were assigned to a separate genus in the past. Species * ''Hemipristis elongata'' (Klunzinger, 1871) * †'' Hemipristis curvatus'' * †''Hemipristis serra'' - An extinct species from the Oligocene-Miocene of Florida, South Carolina, and other areas on the Atlantic coast. See also * List of prehistoric cartilaginous fish This list of prehistoric cartilaginous fish gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paragaleus
''Paragaleus'' is a genus of weasel shark in the family Hemigaleidae. This genus has a rounded or slightly pointed snout, short gill slits, and a broadly arched mouth. The upper teeth have long cusps, and no toothless spaces occur at the jaw midlines. The dorsal and pelvic fins and the lower caudal lobe are not falchate in shape. Known fossil species include '' P. pulchellus'' and '' P. antunesi''. * Whitetip weasel shark (''Paragaleus leucolomatus'') Compagno & Smale, 1985 (whitetip weasel shark* Atlantic weasel shark (''Paragaleus pectoralis'') (Garman Garman is a surname or first name. Notable people with the name include: Sports * Ann Garman, All-American Girls Professional Baseball League player * Judi Garman (born 1954), American softball coach * Mike Garman (born 1949), American baseball pla ..., 1906) (Atlantic weasel shark* Slender weasel shark (''Paragaleus randalli'') Compagno, Krupp & K. E. Carpenter, 1996 (slender weasel shark* Straight-tooth weasel shark (''P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaenogaleus
''Chaenogaleus'' is a genus of shark containing two species. Only one is extant. * Hooktooth shark The hooktooth shark (''Chaenogaleus macrostoma''), is a weasel shark of the family Hemigaleidae, the only extant member of the genus ''Chaenogaleus'', but there is an extinct species, ''Chaenogaleus affinis''. The hooktooth shark is found in the ... (''Chaenogaleus macrostoma'') ( Bleeker, 1852) * †'' Chaenogaleus affinis'' ( Probst, 1879) References {{Taxonbar, from=Q17279641 Shark genera Taxa named by Theodore Gill Hemigaleidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemigaleus
''Hemigaleus'' is a genus of weasel shark in the family Hemigaleidae. It is characterized by a rounded snout and short gill slits. The mouth is short and broadly arched; the teeth have very short cusps, without toothless spaces at the jaw midlines. The dorsal and pelvic fins, and the lower caudal lobe are strongly falchate. At one time or another, this genus has encompassed up to nine species, but most were eventually split off into other genera. ''Neogaleus'' Whitley, 1931 is a junior synonym of this genus. * '' Hemigaleus australiensis'' W. T. White, 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 typically come in pairs and have been made from various materials, including hardwoods, cast iron, an ... & Compagno, 2005 (Australian weasel shark* '' Sicklefin weasel shark, Hemigaleus microstoma'' Bleeker, 1852 (sicklefin weasel shark References {{Taxonbar, from=Q6464276 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaenogaleus Affinis
''Chaenogaleus affinis'' is an extinct species of weasel shark which existed during the Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ... epoch. It was described by Josef Probst in 1879.''Tertiary research, Volumes 20-22'' Tertiary Research Group (Great Britain), 2000. References Chaenogaleus Miocene sharks Neogene fish of Europe {{Shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In contrast, bony fishes have a single outer bony gill covering called an operculum. Most sharks and rays have five pairs of gill slits, but a few species have 6 or 7 pairs. Shark gill slits lie in a row behind the head. The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow. A modified slit, called a spiracle, lies just behind the eye, which assists the shark with taking in water during respiration and plays a major role in bottom–dwelling sharks. Spiracles are reduced or missing in active pelagic sharks. While the shark is moving, water passes through the mouth and over the gills in a process known as "ram ventilation". While at rest, most sharks pump water over their gills ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
