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Pristiophoriformes
A sawshark or saw shark is a member of a shark order (Pristiophoriformes ) bearing a unique long, saw-like rostrum (snout or bill) edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristiophoriformes, including the longnose or common sawshark ('' Pristiophorus cirratus''), shortnose sawshark ('' Pristiophorus nudipinnis''), Japanese sawshark ('' Pristiophorus japonicas''), Bahamas sawshark ('' Pristiophorus schroederi''), sixgill sawshark ('' Pliotrema warreni''), African dwarf sawshark ('' Pristiophorus nancyae''), Lana's sawshark ('' Pristiophorus lanae'') and the tropical sawshark ('' Pristiophorus delicatus''). Sawsharks are found in many areas around the world, most commonly in waters from the Indian Ocean to the southern Pacific Ocean. They are normally found at depths around 40–100 m, but can be found much lower in tropical regions. The Bahamas sawshark was discovered in deeper waters (640 m to 915 m) of the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the Division (taxonomy), division Selachii and are the sister group to the Batoidea, Batomorphi (Batoidea, rays and skate (fish), skates). Some sources extend the term "shark" as an informal category including Extinction, extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as ''Cladoselache'' and ''Doliodus'' first appeared in the Devonian Period (419–359 million years), though some fossilized chondrichthyan-like scales are as old as the Ordovician, Late Ordovician (458–444 million years ago). The earliest confirmed modern sharks (Selachii) are known from the Early Jurassic around , with the oldest known member being ''Agaleus'', though records of true shar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliotrema
''Pliotrema'' is a genus of sawsharks found in the Western Indian Ocean. Members of this genus differ from sawsharks of the genus '' Pristiophorus'' in having six gill slits. The presence of six pairs of gill slits highlights this genus among sharks; outside Hexanchiformes order, ''Pliotrema'' is the only shark genus with more than five gill slits. The genus was formerly monotypic, featuring only ''P. warreni'' until the two new species were described in 2020. Taxonomy The genus name ''Pliotrema'' comes from Ancient Greek ''pléōn'', meaning "many", and ''-trḗma'', meaning "holes". The specific name ''warreni'' honours Ernest Warren (1871–1945), who sent specimens to the British Museum. The specific names of the two new species are named for female relatives of Simon Weigmann, the senior author - his daughter for ''P. kajae'' and his niece for ''P. annae''. Species There are currently three recognized species in this genus: * '' Pliotrema annae'' Weigmann, Gon, Leeney & Tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propristiophorus
''Propristiophorus'' is an extinct genus of sawshark that lived in the Late Cretaceous. It contains a single named species, ''P. tumidens'', from Lebanon. Additional unnamed species have been found in Antarctica, Japan, and Madagascar. ''Propristiophorus'' was previously synonymized with ''Pristiophorus ''Pristiophorus'' is a genus of sawsharks found in the Pacific, Atlantic and Indian oceans. Members of this genus differ from sixgill sawsharks of the genus ''Pliotrema'' in having five gill slits. Their rostral sawteeth lack prominent transver ...'', but more recent authors have considered it a distinct genus. References Pristiophoriformes Fauna of Lebanon Fish of Japan Fish of Madagascar Fish of Antarctica Prehistoric shark genera Cretaceous sharks Monotypic prehistoric cartilaginous fish genera {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliotrema Warreni
The sixgill sawshark, ''Pliotrema warreni'' is a sawshark of the family Pristiophoridae. Unlike other sawsharks, the barbs on this shark's rostrum continue onto the sides of the head. Its barbels are also closer to its mouth than in other species. At maximum, females can reach over long, and males can reach over long. Range and habitat The sixgill sawshark is found in the temperate and subtropical waters of the western Indian Ocean between latitudes 23° S and 37° S, at depths of between . This shark lives in the benthic and benthopelagic zones of the continental shelf. Adults are partially segregated from juveniles, as they naturally tend to aggregate at lower depths. Behavior Using their sensitive barbels and electric sense, sixgill sawsharks are able to find their prey and then incapacitate them with their rostrum. Their known diet includes small fish, crustaceans, and squids. The only observed predator of the sixgill sawshark is the tiger shark, though it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiophorus Delicatus
The tropical sawshark, ''Pristiophorus delicatus'', is a recently described species of sawshark, family Pristiophoridae, formerly known in literature as ''Pristiophorus'' sp. B. It is endemic to northeastern Australia, found on the upper continental slope off Queensland from south of the Samaurez Reef, at a depth of . Its specific epithet ''delicatus'' is Latin for "delicate", referring to the fine teeth on its saw-like rostrum. This is a small species; the maximum known length is for females and for males (although no mature males have yet been examined). The body is slender with a circular cross-section, and depressed forward of the gill slits. The elongated, saw-like snout tapers evenly to its tip, and bears very slender lateral teeth of variable length and a pair of filamentous, dorsoventrally flattened barbels. The eyes are large and oval in shape. Its nostrils about one-third the distance from the corner of the mouth to the barbel attachment on the rostrum.Dianne J. Bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ikamauius
''Ikamauius'' is an extinct genus of sawshark from the Cenozoic of New Zealand. It contains a single species, ''I. ensifer''. It is most closely related to the extant ''Pliotrema ''Pliotrema'' is a genus of sawsharks found in the Western Indian Ocean. Members of this genus differ from sawsharks of the genus '' Pristiophorus'' in having six gill slits. The presence of six pairs of gill slits highlights this genus among sh ...'', but is distinguished by the presence of barbs on both sides of its rostral denticles. References Marine fish of New Zealand Pristiophoriformes Prehistoric shark genera Monotypic prehistoric cartilaginous fish genera {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiophorus
''Pristiophorus'' is a genus of sawsharks found in the Pacific, Atlantic and Indian oceans. Members of this genus differ from sixgill sawsharks of the genus ''Pliotrema'' in having five gill slits. Their rostral sawteeth lack prominent transverse ridges on the basal ledges, and the large teeth are not posteriorly serrated. Taxonomy The genus name ''Pristiophorus'' comes from Ancient Greek ''pristēs'', meaning "saw", and ''-phóros'', meaning "bearing". Species There are currently seven recognized species in this genus: * ''Pristiophorus cirratus'' ( Latham, 1794) (Longnose sawshark) * '' Pristiophorus delicatus'' Yearsley, Last & W. T. White, 2008 (Tropical sawshark) * '' Pristiophorus japonicus'' Günther, 1870 (Japanese sawshark) * '' Pristiophorus lanae'' Ebert & Wilms, 2013 (Lana's sawshark) * ''Pristiophorus nancyae'' Ebert & Cailliet, 2011 (African dwarf sawshark) * ''Pristiophorus nudipinnis'' Günther, 1870 (Shortnose sawshark) * ''Pristiophorus peroniensis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiophorus Nancyae
''Pristiophorus nancyae'', the African dwarf sawshark or dwarf sawshark, is a sawshark of the family Pristiophoridae. The species was discovered in 2011 when a specimen was caught off the coast of Mozambique at a depth of .California Academy of Sciences, "140 NEW SPECIES DESCRIBED BY CALIFORNIA ACADEMY OF SCIENCES IN 2011", California Academy of Sciences - San Francisco Museum and Planetarium - Bay Area Natural History Museum, December 14, 2011.http://www.calacademy.org/newsroom/releases/2011/new_species.php Description Like other sawsharks, the African dwarf sawshark has a long "saw" like snout, or rostrum. The rostrum is edged with pointy teeth that are used for both hunting and defense. This species is noted for its general elongated and slender form and a rostrum roughly 1/3 of its total length. This shark was named by researchers at the Pacific Shark Research Center at Moss Landing Marine Laboratories, the west coast representative of the National Shark Research Consorti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiophorus Lanae
Lana's sawshark (''Pristiophorus lanae'') or the Philippine sawshark, is a sawshark of the family Pristiophoridae, found in the Philippines off Apo Island and southern Luzon at depths of between 230 and 590 m. Its length is up to 73 cm. Max length : 66.9 cm TL male/unsexed, 83.0 cm TL (female) Its reproduction is presumed to be ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo .... References * Compagno, Dando, & Fowler, ''Sharks of the World'', Princeton University Press, New Jersey 2005 Lana's sawshark Endemic fauna of the Philippines Fish of the Philippines Lana's sawshark {{Shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. The Indian Ocean has large marginal or regional seas, including the Andaman Sea, the Arabian Sea, the Bay of Bengal, and the Laccadive Sea. Geologically, the Indian Ocean is the youngest of the oceans, and it has distinct features such as narrow continental shelf, continental shelves. Its average depth is 3,741 m. It is the warmest ocean, with a significant impact on global climate due to its interaction with the atmosphere. Its waters are affected by the Indian Ocean Walker circulation, resulting in unique oceanic currents and upwelling patterns. The Indian Ocean is ecologically diverse, with important ecosystems such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), the Pacific Ocean is the largest division of the World Ocean and the hydrosphere and covers approximately 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area ().Pacific Ocean . ''Encyclopædia Britannica, Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the Land and water hemispheres, water hemisphere and the Western Hemisphere, as well as the Pole of inaccessi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.Gradstein ''et al.'' (2004) Stratigraphic definition The Santonian Stage was established by French geologist Henri Coquand in 1857. It is named after the city of Saintes in the region of Saintonge, where the original type locality is located. The base of the Santonian Stage is defined by the appearance of the inoceramid bivalve ''Cladoceramus undulatoplicatus''. The GSSP (official reference profile) for the base of the Santonian Stage is located near Olazagutia, Spain; it was ratified by the Subcommission on Cretaceous Stratigraphy in 2012. The Santonian's top (the base of the Campanian Stage) is informally marked by the extinction of the crinoid '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
