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Halacaridae
Halacaridae is a family of meiobenthic mites found in marine, brackish, and freshwater habitats around the world. It includes more than 1100 described species belonging to 64 genera It is the largest marine radiation of arachnids. Description and life cycle Halacarids have four pairs of legs (as adults and nymphs; see below), of which the first two pairs point forwards and the last two pairs point backwards. This is a synapomorphy of the group. Another synapomorphy are four plates on the dorsal surface of the body, except for several genera with reduction of certain plates. The life cycle of halacarids consists of egg, larva, 1-3 nymphal stages (protonymph->deutonymph->tritonymph) and adult. Additionally, between each of the free-living stages (i.e. except for the egg) is a quiescent pupal stage. * Eggs are usually deposited by an adult female in a substrate, with the help of an ovipositor. * Larvae have three pairs of legs, with each leg five-segmented, and lack a genital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agaue (arachnid)
''Agaue'' is a genus of arachnids in the family Halacaridae. There are at least four described species in ''Agaue''. Species * ''Agaue chevreuxi'' (Trouessart, 1889) * ''Agaue hamiltoni'' Womersley, 1937 * ''Agaue magellanica'' Newell, 1971 * ''Agaue marginata'' Viets, 1950 References Further reading * * Trombidiformes {{trombidiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mites
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evidence of a close relationship. Most mites are tiny, less than in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others again are predators or parasites. This last type includes the commercially destructive ''Varroa'' parasite of honey bees, as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases. The scientific discipline devoted to the study of mites is called acarology. Evolution and taxonomy The mites are not a defined taxon, but is used for two distinct groups of arachnids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitism
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitengona
Parasitengona is a group of mites, variously ranked as a hyporder or a cohort, between the taxonomic ranks of order and family. They are divided into the aquatic Hydrachnidia (water mites) and the terrestrial Trombidia. The latter includes velvet mites and chiggers. Description Many Parasitengona are relatively large (for mite standards) and have a bright red colouration. Other colours include purple, orange, yellow, blue, green and brown. The terrestrial Trombidia are often hypertrichous, meaning they are covered in many irregularly arranged setae. The chelicerae bases are separate, the fixed cheliceral digit is absent and the movable digit is either hooked or linear. The palps are often raptorial with a claw-like seta on the tibia. The gnathosoma is retractable within group Erythraeina. The stigmata and peritremes, when present, are between the cheliceral bases. In Trombidia, there is usually one or two pairs of trichobothria on the prodorsum, and these are often mounted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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