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Portunoidea
__NOTOC__ Portunoidea is a superfamily of crabs that includes the family Portunidae, the swimming crabs. Which other crab families are also placed here is a matter of some contention, and may be revised following molecular phylogenetic analyses. Description Their rather flat and smooth carapace is usually wider than long and of hexagonal, subhexagonal, rectangular, or transversely ovate shape. It is usually widest between the hindmost spines of the forward rim; there may be up to 9 pairs of these spines, with a few smaller ones right above the head, but they are missing altogether in some species. In some, the first maxilliped's endopod is lobed, forming the characteristic portunid lobe. The chelipeds are usually robust, and in some the last pereiopod pair has ovate dactyls. The sutures of the sternum between segments 4 to 8 are usually incomplete, and in the Portunidae, the eighth sternite is usually visible if seen from below and has a penial groove. In males, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portunidae
Portunidae is a family of crabs which contains the swimming crabs. Its members include well-known shoreline crabs such as the blue crab (''Callinectes sapidus'') and velvet crab ('' Necora puber''). Description Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong, sharp claws, allows many species to be fast and aggressive predators. Taxonomy Swimming crabs reach their greatest species diversity in the Pacific and Indian Oceans. Portunidae consists of the following subfamilies and genera: ;Achelouinae ;Caphyrinae ;Carupinae ;Coelocarcininae ;Lupocyclinae ;Necronectinae ;Podophthalminae ;Portuninae ;Thalamitinae ;''incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geryonidae
Geryonidae is a family of crabs, including the following subfamilies and genera: * Benthochasconinae **'' Benthochascon'' **'' Raymanninus'' *† '' Coeloma'' *'' Coenophthalmus'' *'' Echonilatus'' * Geryoninae **† '' Archaeoplax'' **'' Chaceon'' **''Geryon In Greek mythology, Geryon ( ; , genitive ), also Geryone (, or ), son of Chrysaor and Callirrhoe, the grandson of Medusa and the nephew of Pegasus, was a fearsome giant who dwelt on the island Erytheia of the mythic Hesperides in the far ...'' **'' Zariquieyon'' *† '' Litoricola'' *'' Nectocarcinus'' *† '' Pyrenicola'' References Portunoidea Decapod families {{Eubrachyura-stub ... [...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] |
Ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean, Antarctic/Southern, and Arctic Ocean),"Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, https://www.merriam-webster.com/dictionary/ocean . Accessed March 14, 2021. and are themselves mostly divided into seas, gulfs and Lists of bodies of water#Seawater bodies, subsequent bodies of water. The ocean contains 97% of Water distribution on Earth, Earth's water and is the primary component of Earth's hydrosphere, acting as a huge Ocean heat content, reservoir of heat for Earth's energy budget, as well as for its carbon cycle and water cycl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathildellidae
Mathildellidae is family of crabs belonging to the superfamily Goneplacoidea Goneplacoidea is a superfamily of crabs containing 11 extant families, and two families known only from fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geolo ..., containing the following genera: *'' Beuroisia'' Guinot & Richer de Forges, 1981 *†'' Branchioplax'' Rathbun, 1916 *†'' Coeloma'' A. Milne-Edwards, 1865 *'' Intesius'' Guinot & Richer de Forges, 1981 *'' Mathildella'' Guinot & Richer de Forges, 1981 *'' Neopilumnoplax'' Serène, 1969 *'' Platypilumnus'' Alcock, 1894 *†'' Tehuacana'' Stenzel, 1944 References Goneplacoidea Decapod families {{Eubrachyura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexapodidae
Hexapodidae is a family of crabs, the only family in the superfamily Hexapodoidea. It has traditionally been treated as a subfamily of the family Goneplacidae, and was originally described as a subfamily of Pinnotheridae. Its members can be distinguished from all other true crabs by the reduction of the thorax, such that only seven sternites are exposed, and only four pairs of pereiopods are present. Not counting the enlarged pair of claws, this leaves only six walking legs, from which the type genus ''Hexapus'', and therefore the whole family, takes its name. Some anomuran "crabs", such as porcelain crabs and king crabs also have only four visible pairs of legs. With the exception of '' Stevea williamsi'', from Mexico, all the extant members are found either in the Indo-Pacific oceans, or around the coast of Africa. Fossil record In addition to the extant taxa, the family contains two genera known only from fossils – '' Goniocypoda'' and '' Palaeopinnixa'' – and two furt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contributions To Zoology
''Contributions to Zoology'' (formerly known as ''Bijdragen tot de Dierkunde'') is a scientific journal that started in 1848 as a publication of the Committee in charge of the library of the Dutch Royal Zoological Society "Natura Artis Magistra" and became integrated in the library of the University of Amsterdam in 1939. Since 2019 the journal is published by Brill publishers, Leiden. The journal has been freely available online since 1997. The current editor-in-chief is Ronald Vonk from Naturalis Biodiversity Center, Leiden. Contributions to Zoology solicits high-quality papers in all systematics-related branches of comparative zoology (including paleozoology). Preference is given to manuscripts dealing with conceptual issues and to integrative papers (e.g., ecology and biodiversity, morphology and phylogeny and character state evolution, phylogeny and historical biogeography, systematics and bioinformatics, bioinformatics and biodiversity, habitat disturbance and biogeography, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xanthoidea
Xanthoidea is a Taxonomic rank, superfamily of crabs, comprising seven families. Formerly, a number of other families were included in Xanthoidea, but many of these have since been removed to other superfamilies. These include Carpilioidea, Eriphioidea, Hexapodidae, Hexapodoidea, Pilumnoidea and Trapezioidea. Even in this reduced state, Xanthoidea remains one of the most species-rich superfamilies of crabs. Families The World Register of Marine Species lists the following families: *Antrocarcinidae *Garthiellidae *Linnaeoxanthidae *Nanocassiopidae *Panopeidae *Pseudorhombilidae *Xanthidae References Xanthoidea, Crabs Crustacean superfamilies {{Xanthoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonopod
Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipedes, gonopods are modified arthropod leg, walking or swimming legs. Gonopods may be highly decorated with elaborate structures which may play roles in sperm competition, and can be used to differentiate and identify closely related species. Gonopods generally occur in one or more pairs, as opposed to the single (un-paired) reproductive organs such as the aedeagus of insects or the Opiliones penis, penis of harvestmen. Insects In insects, gonopods are appendages of the genital segment that may be used in insemination, or that comprise the egg-laying apparatus. Crustaceans In male decapoda, decapod crustaceans, gonopods are modified swimming appendages (pleopods). The anterior two pair of pleopods in males are modified for sperm transferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somite
The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryogenesis, embryonic stage of somitogenesis, along the head-to-tail axis in segmentation (biology), segmented animals. In vertebrates, somites subdivide into the #Dermatome, dermatomes, #Myotome, myotomes, #Sclerotome, sclerotomes and #Syndetome, syndetomes that give rise to the vertebrae of the vertebral column, rib cage, part of the occipital bone, skeletal muscle, cartilage, tendons, and dermis, skin (of the back). The word ''somite'' is sometimes also used in place of the word ''Metamerism (biology), metamere''. In this definition, the somite is a Homology (biology), homologously-paired structure in an animal body plan, such as is visible in annelids and arthropods. Development The mesoderm forms at the same time as the other two germ layers, the ectoderm and endoderm. The mesoderm at either side of the neural tube is called paraxial mesoderm. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
