|
Hippoidea
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] |
Blepharipodidae
Blepharipodidae is a family of sand crabs (Hippoidea), comprising the two genera '' Blepharipoda'' and '' Lophomastix''. They are distinguished from the other families in the superfamily Hippoidea by the form of the gills, which are trichobranchiate (filamentous) in Blepharipodidae, but phyllobranchiate (lamellar) in Albuneidae and Hippidae. Fossils belonging to the genus ''Lophomastix'' have been found in rocks dating back to the Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes .... References Hippoidea Decapod families {{Anomura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squat Lobster
Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside groups including the hermit crabs and mole crabs. They are distributed worldwide in the oceans, and occur from near the surface to deep sea hydrothermal vents, with one species occupying caves above sea level. More than 900 species have been described, in around 60 genera. Some species form dense aggregations, either on the sea floor or in the water column, and a small number are commercially fished. Description The two main groups of squat lobsters share most features of their morphology. They resemble true lobsters in some ways, but are somewhat flattened dorsoventrally, and are typically smaller, ranging from 0.7 to 3.5 inches in length. Squat lobsters vary in postorbital carapace length (measured from the eye socket to the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blepharipoda Occidentalis
''Blepharipoda'' is a genus of mole crabs 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 ..., containing the following species: '' Blepharipoda liberata'' is harvested for food in China. References Hippoidea {{Anomura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomura
Anomura (sometimes Anomala) is a group of decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word ''crab'', all true crabs are in the sister group to the Anomura, the Brachyura (the two groups together form the clade Meiura). Description The name Anomura derives from an old classification in which Reptantia, reptant decapods were divided into Macrura (long-tailed), Brachyura (short-tailed) and Anomura (differently-tailed). The alternative name Anomala reflects the unusual variety of forms in this group; whereas all crabs share some obvious similarities, the various groups of anomurans are quite dissimilar. The group has been moulded by several instances of carcinisation – the development of a crab-like body form. Thus, the king crabs (Lithodidae), porcelain crabs (Porcellanidae) and hairy stone crab (Lomisidae) are all separate instances of carcinisation. As decapods (meaning ''ten-legged''), anomurans have ten pereiopods, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippidae
Hippidae is a family of decapod crustaceans, currently known by the English name as either mole crab or sand crab, and by an earlier English name as sand bug. They are closely related to the family Albuneidae, with which they are usually joined in the superfamily Hippoidea. The family Hippidae comprises the three genera '' Emerita'', ''Hippa'' and '' Mastigochirus''. They burrow into sand, and are found throughout the world, except the Arctic and Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar .... References Hippoidea Decapod families {{Anomura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albuneidae
Albuneidae is a little-known family of specialized burrowing sand crabs. There are 50 extant species as well as nine fossil species that have been described. Fossil specimens have been described from the Cretaceous, Miocene and 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 .... References Further reading * Hippoidea Decapod families {{Anomura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decapoda
The Decapoda or decapods, from Ancient Greek δεκάς (''dekás''), meaning "ten", and πούς (''poús''), meaning "foot", is a large order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, and prawns. Most decapods are scavengers. The order is estimated to contain nearly 15,000 extant species in around 2,700 genera, with around 3,300 fossil species. Nearly half of these species are crabs, with the shrimp (about 3,000 species) and Anomura including hermit crabs, king crabs, porcelain crabs, squat lobsters (about 2500 species) making up the bulk of the remainder. The earliest fossils of the group date to the Devonian. Anatomy Decapods can have as many as 38 appendages, arranged in one pair per body segment. As the name Decapoda (from the Greek , ', "ten", and , '' -pod'', "foot") implies, ten of these appendages are considered legs. They are the pereiopods, found on the last five thoracic segments. In many decapods, one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beach
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from Rock (geology), rock, such as sand, gravel, shingle beach, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material. Though some beaches form on inland freshwater locations such as lakes and rivers, most beaches are in coastal areas where wind wave, wave or Ocean current, current action deposition (geology), deposits and reworks sediments. Coastal erosion, Erosion and changing of beach geologies happens through natural processes, like wave action and Extreme weather, extreme weather events. Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for the beach. However, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walk
Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined as an "inverted pendulum" gait in which the body vaults over the stiff limb or limbs with each step. This applies regardless of the usable number of limbs—even arthropods, with six, eight, or more limbs, walk. In humans, walking has health benefits including improved mental health and reduced risk of cardiovascular disease and death. Difference from running The word ''walk'' is descended from the Old English ''wealcan'' 'to roll'. In humans and other bipeds, walking is generally distinguished from running in that only one foot at a time leaves contact with the ground and there is a period of double-support. In contrast, running begins when both feet are off the ground with each step. This distinction has the status of a formal requirement in competitive walking events. For quadrupedal speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galatheoidea
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus '' Palaeomunidopsis''. Classification These families and genera are included: ; Galatheidae *† '' Acanthogalathea'' – Upper Eocene * '' Alainius'' * '' Allogalathea'' * '' Allomunida'' * '' Coralliogalathea'' * '' Fennerogalathea'' * '' Galathea'' * '' Janetogalathea'' * '' Lauriea'' *† '' Lessinigalathea'' – Lower Eocene *† '' Lophoraninella'' – Upper Cretaceous *† '' Luisogalathea'' – Upper Cretaceous * '' Macrothea'' *† '' Mesogalathea'' – Upper Jurassic to Cretaceous * '' Nanogalathea'' *† '' Palaeomunida'' – Upper Jurassic to Oligocene * '' Phylladiorhynchus'' *† '' Spathagalathea'' – Upper Eo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermit Crab
Hermit crabs are anomuran Decapoda, decapod crustaceans of the superfamily (taxonomy), superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-Marine biogenic calcification, calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless. The strong association between hermit crabs and their shelters has significantly influenced their biology. Almost 800 species carry mobile shelters (most often calcified Gastropod shell, snail shells); this protective mobility contributes to the diversity and multitude of these crustaceans which are found in almost all marine environments. In most species, development involves metamorphosis from symmetric, free-swimming larvae to morphologically asymmetric, benthic zone, benthic-dwellin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
