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Raninidae
Raninidae is a family of unusual crabs, sometimes known as "frog crabs", on account of their frog-like appearance. They are taken by most scientists to be quite primitive among the true crabs. They closely resemble the (unrelated) mole crabs, due to parallel evolution or convergent evolution. In both groups, the claws are modified into tools for digging, and the body is a rounded shape that is easy to bury in sand. Unlike most other true crabs, the abdomens of raninids are not curled under the cephalothorax. They spend most of their time buried in the sand with their eyes popping out so they can grab unaware prey. They also emerge for mating. Raninids are omnivores and some have been found to have consumed Sardinella, crab, shrimp, bivalve, ray, hydroid, copepod, and squid. The earliest fossil attributable to the family Raninidae dates from the Albian. Description Raninids dorsal surfaces have varying textures; smooth, pitted, granular, inclined or fungiform nodes, eroded, sc ... [...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] |
Eumorphocorystes
''Eumorphocorystes'' is a genus of crab belonging to the Raninidae subfamily Notopodinae. Fossils of the genus have been found in the Late Cretaceous (Maastrichtian) Maastricht Formation of the Netherlands. Rathbun referred specimens from the Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ... Stepovak Formation of Alaska to this genus. References Crabs Prehistoric Malacostraca Prehistoric crustacean genera Late Cretaceous crustaceans Eocene crustaceans Oligocene crustaceans Maastrichtian genus first appearances Oligocene genus extinctions Cretaceous–Paleogene boundary Fossils of Alaska Fossil taxa described in 1857 Paleocene crustaceans Oligocene Alaska Cretaceous Netherlands Late Cretaceous arthropods of Europe Oligocene arthropods of North Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyreidus Tridentatus
''Lyreidus tridentatus'' is a species of crab in the family Raninidae. Description This species as an unusual carapace in that it is longer than it is wide. Males grow to about 5.2 cm long and 1.3 cm wide. Females grow to 3 cm wide and about 4.9 cm long. They have a reddish to reddish-brown body, with a reticulated pattern. The pereopods are pale-pinkish tan colour. Distribution ''Lyreidus tridentatus'' occurs in Australia, New Zealand, New Caledonia, China, Taiwan, Japan, Fiji, and Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat .... Habitat This species lives on shelves and slope substrates in sandy mud. References External links Image Crabs Crustaceans described in 1841 {{Crab-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notopus
''Notopus'' is a genus of frog crabs from the family Raninidae, it consists of a single extant species and two extinct species. Species The three species classified under ''Notopus'' are set out below together with the geological frame for the two extinct species which are marked with †: *''Notopus beyrichi''† Bittner, 1875 - middle Eocene-lower Oligocene * ''Notopus dorsipes'' (Linnaeus, 1758) * ''Notopus muelleri''† (van Binkhorst, 1857) - upper Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ... References {{Taxonbar, from=Q18594949 Crabs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyreidus
''Lyreidus'' is a genus of crabs in the family Raninidae, containing the following species: *'' Lyreidus brevifrons'' Sakai, 1937 *'' Lyreidus stenops'' Wood-Mason, 1887 *''Lyreidus tridentatus ''Lyreidus tridentatus'' is a species of crab in the family Raninidae. Description This species as an unusual carapace in that it is longer than it is wide. Males grow to about 5.2 cm long and 1.3 cm wide. Females grow to 3 cm wi ...'' de Haan, 1841 References Crabs {{Crab-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole Crab
Hippoidea is a superfamily of decapod crustaceans known as sand crabs or mole crabs. Ecology Hippoids are adapted to burrowing into sandy beaches, a habit they share with raninid crabs, and the parallel evolution of the two groups is striking. In the family Hippidae, the body is almost ovoid, the first pereiopods have no claws, and the telson is long, none of which are seen in related groups. Unlike most other decapods, sand crabs cannot walk; instead, they use their legs to dig into the sand. Members of the family Hippidae beat their uropods to swim. Apart from the polar regions, hippoids can be found on beaches throughout the world. Larvae of one species have also been found in Antarctic waters, despite the lack of suitable sandy beaches in the Antarctic. Classification Alongside hermit crabs and allies (Paguroidea), squat lobsters and allies (Galatheoidea) and the hairy stone crab (''Lomis hirta'', Lomisoidea), Hippoidea is one of the four groups that make up the infraord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ranina Ranina
''Ranina ranina'', also known as the Huỳnh Đế crab, (red) frog crab or spanner crab, is a species of crab found throughout tropical and subtropical habitats. It is often fished for its meat, and is the only known species in its genus. Description It may grow up to long, and may weigh up to . The carapace is wider at the front, reddish brown in color, with ten white spots. ''Ranina ranina'' is mainly nocturnal, and remains buried in the sand during the day. ''Ranina ranina'' is easily distinguished from other crab species in its habitat due to its red carapace and elongated midsection. Distribution and ecology Spanner crabs inhabit coastal waters along the east coast of Australia, from Yeppoon in Queensland to the North coast of New South Wales. There is also a population to the north of Perth in Western Australia. ''Ranina ranina'' is abundant in the coastal waters of south-western Mindanao, Philippines. These crabs are also found in the eastern coast of Africa, across the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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