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Hourglass Dolphin
The hourglass dolphin (''Lagenorhynchus cruciger'') is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage, but has a circumpolar distribution. The species was identified as a new species by Jean René Constant Quoy and Joseph Paul Gaimard in 1824 from a drawing made in the South Pacific in 1820. It is the only cetacean to have been widely accepted as a species solely on witness accounts. Description The hourglass dolphin is colored black on top and white on the belly, with white patches on the sides and sometimes variations of dark grey. For this reason, it was colloquially known by whalers as a "sea cow" (although it does not belong to the taxonomic order Sirenia) or "sea skunk". Each flank has a white patch at the front, above the beak, eye and flipper, and a second patch at the rear. These two patches are connected by a thin white strip, creating, loosely speaking, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drake Passage
The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atlantic Ocean (Scotia Sea) with the southeastern part of the Pacific Ocean and extends into the Southern Ocean. The Drake Passage is considered one of the most treacherous voyages for ships to make. Currents at its latitude meet no resistance from any landmass, and waves top , hence its reputation as "the most powerful convergence of seas". As the Drake Passage is the narrowest passage around Antarctica, its existence and shape strongly influence the circulation of water around Antarctica and the global oceanic circulation, as well as the global climate. The bathymetry of the Drake Passage plays an important role in the global mixing of oceanic water. It is one of the most treacherous bodies of water on earth. History Sailing south from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tierra Del Fuego
Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla Grande de Tierra del Fuego, with an area of , and a group of many islands, including Cape Horn and Diego Ramírez Islands. Tierra del Fuego is divided between Chile and Argentina, with the latter controlling the eastern half of the main island and the former the western half plus the islands south of Beagle Channel and the southernmost islands. The southernmost extent of the archipelago is just north of latitude 56°S. The earliest known human settlement in Tierra del Fuego dates to approximately 8,000 BC. Europeans first explored the islands during Ferdinand Magellan's expedition of 1520. ''Tierra del Fuego'' and similar namings stem from sightings of the many bonfires that the natives built. Settlement by those of European descent and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hector's Dolphin
Hector's dolphin (''Cephalorhynchus hectori'') is one of four dolphin species belonging to the genus ''Cephalorhynchus''. Hector's dolphin is the only cetacean endemic to New Zealand, and comprises two subspecies: ''C. h. hectori'', the more numerous subspecies, also referred to as South Island Hector's dolphin; and the critically endangered Māui dolphin (''C. h. maui''), found off the West Coast of the North Island. Etymology Hector's dolphin was named after Sir James Hector (1834–1907), who was the curator of the Colonial Museum in Wellington (now the Museum of New Zealand Te Papa Tongarewa). He examined the first specimen of the dolphin found by cephologists. The species was scientifically described by Belgian zoologist Pierre-Joseph van Beneden in 1881. Māori names for Hector's and Māui dolphin include ''tutumairekurai, tupoupou'' and ''popoto''. Description Hector's dolphin is the smallest dolphin species. Mature adults have a total length of and weigh .Slooten, E. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagmatias
''Sagmatias'' was a genus of Dolphin, dolphins, defined in 1866 by Edward Drinker Cope with Peale's dolphin as type species, described as ''Sagmatias amblodon''. It has been proposed to resurrect the genus to include four species of oceanic dolphins currently classified in the genus ''Lagenorhynchus''. Mitochondrial DNA studies have indicated that Pacific white-sided dolphin, Peale's dolphin, dusky dolphin and hourglass dolphin are more closely related to dolphins in the Lissodelphininae subfamily, than to the two other members of the genus: Atlantic white-sided dolphin and white-beaked dolphin. This phylogenetic relationship is further supported by cladistic analysis of morphological characters. However, resurrection of the genus ''Sagmatias'' has not been accepted by the Society for Marine Mammalogy's taxonomic Committee, because the finer details of the phylogenetic relationships between the four species in the proposed ''Sagmatias'' genus and the four species of dolphins in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalorhynchus
''Cephalorhynchus'' is a genus in the dolphin family Delphinidae. Extant species It consists of four species: The species have similar physical features—they are small, generally playful, blunt-nosed dolphins—but they are found in distinct geographical locations. A phylogenetic analysis by indicated the two species traditionally assigned to the genus ''Lagenorhynchus'', the hourglass dolphin ''L. cruciger'' and Peale's dolphin Peale's dolphin (''Lagenorhynchus australis'') is a small dolphin found in the waters around Tierra del Fuego at the foot of South America. It is also commonly known as the black-chinned dolphin or even Peale's black-chinned dolphin. However, si ... ''L. australis'' are actually phylogenetically nested among the species of ''Cephalorhynchus'', and they suggest these two species should be transferred to the genus ''Cephalorhynchus''. Some acoustic and morphological data support this arrangement, at least with respect to Peale's dolphin. Accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagenorhynchus
''Lagenorhynchus'' is a genus of oceanic dolphins in the infraorder Cetacea, presently containing six extant species. However, there is consistent molecular evidence that the genus is polyphyletic and several of the species are likely to be moved to other genera. In addition, the extinct species ''Lagenorhynchus harmatuki'' is also classified in this genus. Etymology The name ''Lagenorhynchus'' derives from the Greek ''lagenos'' meaning "bottle" and ''rhynchus'' meaning "beak". Indeed, the "bottle-nose" is a characteristic of this genus. However, the dolphins popularly called bottlenose dolphins belong in the genus '' Tursiops''. Taxonomy There is compelling evidence from molecular phylogeny that the genus ''Lagenorhynchus'' is polyphyletic, meaning that it currently contains several species that are not closely related. found that the white-beaked and Atlantic white-sided dolphins are phylogenetically isolated within the Delphinidae, where they are believed to be rather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaimard
Joseph Paul Gaimard (31 January 1793 – 10 December 1858) was a French naval surgeon and naturalist. Biography Gaimard was born at Saint-Zacharie on January 31, 1793. He studied medicine at the naval medical school in Toulon, subsequently earning his qualifications as a naval surgeon. Along with Jean René Constant Quoy, he served as naturalist on the ships ''L'Uranie'' under Louis de Freycinet 1817–1820, and '' L'Astrolabe'' under Jules Dumont d'Urville 1826–1829.Google Books Discovery of Australia's Fishes: A History of Australian Ichthyology to 1930 by Brian Saunders During this voyage they discovered the now extinct giant of |
Squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting these criteria. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius (cephalopod), gladius or pen, made of chitin. Squid diverged from other cephalopods during the Jurassic and occupy a similar role to teleost fish as open water predators of similar size and behaviour. They play an important role in the open water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swallowing. Squid are rapid swimmers, moving by Aquatic locomotion#Jet propulsion, jet propulsion, and largely locate their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaete Worms
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known from f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantis Shrimp
Mantis shrimp, or stomatopods, are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around in length, while a few can reach up to . A mantis shrimp's carapace (the hard, thick shell that covers crustaceans and some other species) covers only the rear part of the head and the first four segments of the thorax. Varieties range in colour from shades of brown to vivid colours, with more than 450 species of mantis shrimp known. They are among the most important predators in many shallow, tropical and subtropical marine habitats. However, despite being common, they are poorly understood, as many species spend most of their lives sheltering in burrows and holes. Called "sea locusts" by ancient Assyrians, "prawn killers" in Australia, and now sometimes referred to as "thumb splitters"—because of the animal's ability to inflict painful woun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow Riding
Cetacean intelligence is the cognitive ability of the infraorder Cetacea of mammals. This order includes whales, porpoises, and dolphins. Brain size Brain size was previously considered a major indicator of the intelligence of an animal. However, many other factors also affect intelligence, and recent discoveries concerning bird intelligence have called into question the influence of brain size. Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase the amount of brain mass available for more complex cognitive tasks. Allometric analysis indicates that in general, mammalian brain size scales at approximately the or exponent of body mass. Comparison of actual brain size with the size expected from allometry provides an encephalization quotient (EQ) that can be used as a more accurate indicator of an animal's intelligence. * Sperm whales (''Physeter macrocephalus'') have the largest known brain mass of any extant animal, av ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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