|
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, erode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropod anatomy), thorax. Their exoskeleton is often Sclerotization, thickened and hard. They generally have Arthropod leg, five pairs of legs, and they have "Pincers (tool), pincers" or "claws" on the ends of the frontmost pair, scientifically termed the ''chelae''. They are present in all the world's oceans, Freshwater crab, in freshwater, and Terrestrial crab, on land, often hiding themselves in small crevices or burrowing into sediment. Crabs are omnivores, feeding on a variety of food, including a significant proportion of Algae eater, algae, as well as Detritivore, detritus and other invertebrates. Crab meat, Crabs are widely consumed by humans as food, with over 1.5 million tonnes Crab fisheries, caught annually. True crabs first appeared ... [...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 (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ... 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
''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. References External links Image Crabs Crustaceans described in 1841 {{Raninoida-stub ...'' de Haan, 1841 References Crabs {{Raninoida-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 International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ... References {{Taxonbar, from=Q18594949 Crabs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole Crab
Hippoidea is a superfamily of decapod crustaceans known as mole crabs or sand 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 in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frog
A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough skin texture due to wart-like parotoid glands tend to be called toads, but the distinction between frogs and toads is informal and purely cosmetic, not from taxonomy (biology), taxonomy or evolutionary history. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest and associated wetlands. They account for around 88% of extant amphibian species, and are one of the five most diverse vertebrate orders. The oldest fossil "proto-frog" ''Triadobatrachus'' is known from the Early Triassic of Madagascar (250Myr, million years ago), but molecular clock, molecular clock dating suggests their divergent evolution, divergence from other amphibians may exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
