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Hypothalassia Acerba
''Hypothalassia acerba'' is a large crab found in the muddy substrates of the deep seas off the southwestern Australian and New Zealand coasts. Australian distribution, which is correlated to depth and temperature, ranges from a latitude as far north as approximately 27° S on the west coast, southwards, then eastwards on the south coast to a longitude of at least 129° E. The species usually occurs in waters with temperatures of and in depths ranging of on the lower west coast and on the south coast. Body size is inversely related to depth of water. There are only two species in the genus '' Hypothalassia'', and ''H. acerba'' is not the same ''champagne crab'' as the other ''Hypothalassia'' species, '' H. armata'', which is found in Japanese waters. Description The species has well-defined groves on a hexagonal carapace, with a smooth dorsal surface and a spiny anterior surface. Carapace width is 150 mm. Their branchial openings are partially covered by maxillipeds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period. Description Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a pair of chelae (claws). Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to . Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation. Environment Crabs are found in all of the world's oceans, as well as in fresh w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilliped
An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including antennae, mouthparts (including mandibles, maxillae and maxillipeds), gills, locomotor legs ( pereiopods for walking, and pleopods for swimming), sexual organs (gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages. An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod. In vertebrates, an appendage can refer to a locomotor part such as a tail, fins on a fish, limbs (legs, flippers or wings) on a tetrapod; exposed sex organ; defensive parts such as horns and antlers; or sensory organs such as auricles, proboscis ( trunk and snout) and barbels. Appendages may become ''uniramous'', as in insects and centipedes, where each appendage comprises a single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaceon Bicolor
''Chaceon bicolor'' is a species of crab.Manning, Raymond B., and L. B. Holthuis. "Two new genera and nine new species of geryonid crabs (Crustacea, Decapoda, Geryonidae)." Proceedings of the Biological Society of Washington 102.1 (1989): 50-77. ''Chaceon bicolor'' differs from all species of the genus in color pattern, with the anterior part of the body purplish rather than reddish. In addition to color pattern, ''C. bicolor'' also differs from '' C. granulatus'' in having compressed rather than depressed dactyli on the walking legs; also, the hepatic region of the carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ... in ''C. granulatus'' is coarsely granular, whereas it is smooth in ''C. bicolor''. Juvenile specimens differ from adults in many features: the teeth of the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leeuwin Current
The Leeuwin Current is a warm ocean current which flows southwards near the western coast of Australia. It rounds Cape Leeuwin to enter the waters south of Australia where its influence extends as far as Tasmania. Discovery The existence of the current was first suggested by William Saville-Kent in 1897. Saville-Kent noted the presence of warm tropical water offshore in the Houtman Abrolhos, making the water there in winter much warmer than inshore at the adjacent coast. The existence of the current was confirmed over the years, but not characterised and named until Cresswell and Golding did so in the 1980s. Track The West Australian Current and Southern Australian Countercurrent, which are produced by the West Wind Drift on the southern Indian Ocean and at Tasmania, respectively, flow in the opposite direction, producing one of the most interesting oceanic current systems in the world. The ‘core’ of the Leeuwin Current can generally be detected as a peak in the surface te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fecund
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to produce offspring, measured by the number of gametes (eggs), seed set, or asexual propagules. Superfecundity refers to an organism's ability to store another organism's sperm (after copulation) and fertilize its own eggs from that store after a period of time, essentially making it appear as though fertilization occurred without sperm (i.e. parthenogenesis). Human demography Human demography considers only human fecundity, at its culturally differing rates, while population biology studies all organisms. The term ''fecundity'' in population biology is often used to describe the rate of offspring production after one time step (often annual). In this sense, fecundity may include both birth rates and survival of young to that time step. Whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawn (biology)
Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and marine reptile, reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing Ovum, ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oviposition
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typically its form is adapted to functions such as preparing a place for the egg, transmitting the egg, and then placing it properly. For most insects, the organ is used merely to attach the egg to some surface, but for many parasitic species (primarily in wasps and other Hymenoptera), it is a piercing organ as well. Some ovipositors only retract partly when not in use, and the basal part that sticks out is known as the scape, or more specifically oviscape, the word ''scape'' deriving from the Latin word '' scāpus'', meaning "stalk" or "shaft". In insects Grasshoppers use their ovipositors to force a burrow into the earth to receive the eggs. Cicadas pierce the wood of twigs with their ovipositors to insert the eggs. Sawflies slit the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dactylus
The dactylus is the tip region of the tentacular club of cephalopods and of the leg of some crustaceans (see arthropod leg). In cephalopods, the dactylus is narrow and often characterized by the asymmetrical placement of suckers (i.e., the ventral expansion of the club) and the absence of a dorsal protective membrane. In crustaceans, the dactylus is the seventh and terminal segment of their thoracic appendages. In certain instances the dactylus, together with the propodus, form the claw. The term ''dactylus'' means "finger" in Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor .... References Cephalopod zootomy Crustacean anatomy {{Animal anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seta
In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. They help, for example, earthworms to attach to the surface and prevent backsliding during peristaltic motion. These hairs make it difficult to pull a worm straight from the ground. Setae in oligochaetes (a group including earthworms) are largely composed of chitin. They are classified according to the limb to which they are attached; for instance, notosetae are attached to notopodia; neurosetae to neuropodia. Crustaceans have mechano- and chemosensory setae. Setae are especially present on the mouthparts of crustaceans and can also be found on grooming limbs. In some cases, setae are modified into scale like structures. Setae on the legs of krill and other small crustaceans help them to gather phytoplankton. It captures them and allows th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheliped
A chela ()also called a claw, nipper, or pinceris a pincer-like organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through New Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds. Another name is ''claw'' because most chelae are curved and have a sharp point like a claw. Chelae can be present at the tips of arthropod legs as well as their pedipalps. Chelae are distinct from spider chelicerae in that they do not contain venomous glands and cannot distribute venom. See also * Pincer (biology) * Pincer (tool) Pincers are a hand tool used in many situations where a mechanical advantage is required to pinch, cut or pull an object. Pincers are first-class levers, but differ from pliers in that the concentration of force is either to a point, or to an ... References Arthropod anatomy {{Arthropod-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron. Crustaceans In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum (anatomy), rostrum. The carapace is Calcification, calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and Isopoda, isopods, but isopods only have a developed "cephalic shield" carapace covering the head. Arachnids In arachnids, the carapace is formed by the fusion of prosomal tergites into a single Plate (animal anatomy), plate which carries the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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