Parasitengona is a group of

mite 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 evid ...

s, variously ranked as a hyporder or a cohort, between the

taxonomic rank In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family (biology), family, order (biology), order, class (b ...

s of

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

and

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

. They are divided into the aquatic

Hydrachnidia Hydrachnidia, also known as "water mites", Hydrachnidiae, Hydracarina or Hydrachnellae, are among the most abundant and diverse groups of benthic arthropods, composed of 6,000 described species from 57 families. As water mites of Africa, Asia, ...

(water mites) and the terrestrial Trombidia. The latter includes velvet mites and

chiggers ''Trombicula'', known as chiggers, red bugs, scrub-itch mites, or berry bugs, are small arachnids (eight-legged arthropods) in the Trombiculidae family. In their larval stage, they attach to various animals, including humans, and feed on skin, ...

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 In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

. 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 The gnathosoma (from Greek , ' = "jaw" and , ' = "body") is the part of the body of the Acari (mites and ticks) comprising the mouth and feeding parts. These are the hypostome, the chelicerae and the pedipalps. It is also called the capitulum (howe ...

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 Trichobothria (singular trichobothrium) are elongate setae ("hairs") present in arachnids, various orders of insects, and myriapods that function in the detection of airborne vibrations and currents, and electrical charge. In 1883, Friedrich Dahl ...

on the prodorsum, and these are often mounted on a linear sclerotised plate (crista metopica). There are almost always well-developed eye lenses. Genital papillae are usually present but vary in their size and number. Eggs of Trombidia are usually reddish, but those within superfamily Erythraeoidea are brown-black due to a

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

cover. Eggs of Hydrachnidia have a gelatinous sheath.

Life cycle and reproduction

The life cycle of Parasitengona consists of the egg, prelarva, larva, protonymph (also known as the nymphochrysalis), deutonymph, tritonymph (imagochrysalis) and adult. The larva, deutoynmph and adult stages are active, while the remaining stages are inactive. The deutonymph is usually the primary growth stage. However, larvae of species of ''

Trombidium ''Trombidium'' is a genus of mite with about 30 described species. Species * '' Trombidium auroraense'' Vercammen-Grandjean, Van Driesche & Gyrisco, 1977 – New York * '' Trombidium breei'' Southcott, 1986 – Europe (host: ''Agapetes galathea' ...

'' and '' Eutrombidium'' (Trombidia) and '' Eylais'' and ''

Hydrachna ''Hydrachna'' is a genus of mites in the family Hydrachnidae, the sole genus of the family. There are more than 80 described species in ''Hydrachna''. Species These 87 species belong to the genus ''Hydrachna'': * ''Hydrachna analis'' Viets & K. ...

'' (Hydrachnidia) can grow additional

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

without

moulting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

(neosomy), so these species grow most in the larval stage. Almost all parasitengones have two distinct sexes (

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

). Males transfer sperm to females indirectly via stalked spermatophores. Female lay eggs usually in one to three clutches.

Ecology

Larvae of Parasitengona are usually ectoparasites of arthropods, and they make up most of the red mites that can be found attached to arthropods. Some (e.g. chiggers) use vertebrates as hosts instead. There are also species with free-living larvae. Some examples are larval ''Neotrombidium beeri'', which live beneath elytra of false mealworm beetles, and larval '' Arrenurus'', which parasitise Odonata. Twenty-one species across six families are myrmecophilous, meaning they are associated with ants. Non-biting midges ( Chironomidae) are the most common host for water mites, while

crane flies Crane fly is a common name referring to any member of the insect family Tipulidae. Cylindrotominae, Limoniinae, and Pediciinae have been ranked as subfamilies of Tipulidae by most authors, though occasionally elevated to family rank. In the most ...

(Tipulidae) are hosts for both water mites and Trombidia. Deutonymphs and adults are usually predators on other arthropods, especially immobile life stages such as eggs and pupae. Again, some species have other diets, such as species of ''

Balaustium ''Balaustium'' is a genus of mites belonging to the family Erythraeidae. These are large red mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, whic ...

'' that feed on pollen or on the sap of plants.

Phylogeny

According to a molecular

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis using the genes 18S, 28S and COI, Hydrachnidia (water mites) is nested within Trombidia (terrestrial parasitengone mites) and the

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 t ...

to Calyptostomatoidea, Stygothrombioidea is the sister group to all other Parasitengona, Erythraeoidea and Tanaupodoidea are sister groups, and Trombiculoidea is a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

clade along with Chyzerioidea in relation to Trombidioidea.

Taxonomy

As of 2011, the taxonomic composition of Parasitengona was as follows: * Superfamily Calyptostomatoidea Oudemans, 1923 ** Family Calyptostomatidae Oudemans, 1923 * Superfamily Erythraeoidea Robineau-Desvoidy, 1828 ** Family

Erythraeidae Erythraeidae is a family of mites belonging to the Trombidiformes. Larval forms of these mites are parasitic on various other arthropods, for example harvestmen, but the adults are free-living predators. These oval mites are rather large, usually ...

Robineau-Desvoidy, 1828 ** Family

Smarididae Smarididae is a family of mites belonging to the order Trombidiformes. These large predatory mites have long oval bodies, distinctively pointed in front. They are usually red and densely hairy with slender legs, sometimes very long. They have e ...

Kramer, 1878 ** Family † Proterythraeidae Vercammen-Grandjean, 1973 * Superfamily Amphotrombioidea Zhang, 1998 ** Family Amphotrombiidae Zhang, 1998 * Superfamily Allotanaupodoidea Zhang & Fan, 2007 ** Family Allotanaupodidae Zhang & Fan, 2007 * Superfamily Chyzerioidea Womersley, 1954 ** Family Chyzeriidae Womersley, 1954 * Superfamily Tanaupodoidea Thor, 1935 ** Family

Tanaupodidae Tanaupodidae is a family of mites belonging to the order Trombidiformes The Trombidiformes are a large, diverse order of mites. Taxonomy In 1998, Trombidiformes was divided into the Sphaerolichida and the Prostigmata. The group has few syna ...

Thor, 1935 * Superfamily Trombiculoidea Ewing, 1929 ** Family Johnstonianidae Thor, 1935 ** Family Neotrombidiidae Feider, 1959 ** Family Trombellidae Leach, 1815 ** Family Leeuwenhoekiidae Womersley, 1944 ** Family

Trombiculidae Trombiculidae (); commonly referred to in North America as chiggers and in Britain as harvest mites, but also known as berry bugs, bush-mites, red bugs or scrub-itch mites, are a family of mites. Chiggers are often confused with Tunga penetrans, ...

Ewing, 1929 ** Family Walchiidae Ewing, 1946 ** Family Audyanidae Southcott, 1987 * Superfamily Trombidioidea Leach, 1815 ** Family Achaemenothrombiidae Saboori, Wohltmann & Hakimitabar, 2010 ** Family Neothrombiidae Feider, 1959 ** Family

Microtrombidiidae Microtrombidiidae is a family of micro velvet mites in the order Trombidiformes The Trombidiformes are a large, diverse order of mites. Taxonomy In 1998, Trombidiformes was divided into the Sphaerolichida and the Prostigmata. The group has f ...

Thor, 1935 ** Family

Trombidiidae Trombidiidae, also known as red velvet mites, true velvet mites, or rain bugs, are small arachnids (eight-legged arthropods) found in plant litter and are known for their bright red color. While adults are typically in length, some, such as t ...

Leach, 1815 * Superfamily Yurebilloidea Southcott, 1996 ** Family Yurebillidae Southcott, 1996 * Superfamily Hydryphantoidea Piersig, 1896 ** Family

Hydryphantidae Hydryphantidae is a family of mites in the order Trombidiformes The Trombidiformes are a large, diverse order of mites. Taxonomy In 1998, Trombidiformes was divided into the Sphaerolichida and the Prostigmata. The group has few synapomorphi ...

Piersig, 1896 ** Family Hydrodromidae Viets, 1936 ** Family Rhynchohydracaridae Lundblad, 1936 ** Family Teratothyadidae Viets, 1929 ** Family Ctenothyadidae Lundblad, 1936 ** Family Thermacaridae Sokolow, 1927 ** Family Zelandothyadidae Cook, 1983 ** Family Malgasacaridae Tuzovskij, Gerecke & Goldschmidt 2007 * Superfamily Eylaoidea Leach, 1815 ** Family Eylaidae Leach, 1815 ** Family Limnocharidae Grube, 1859 ** Family Piersigiidae Oudemans, 1902 ** Family Apheviderulicidae Gerecke, Smith & Cook, 1999 * Superfamily Hydrovolzioidea Thor, 1905 ** Family Hydrovolziidae Thor, 1905 ** Family Acherontacaridae Cook, 1967 * Superfamily Hydrachnoidea Leach, 1815 ** Family Hydrachnidae Leach, 1815 * Superfamily Lebertioidea ** Family Bandakiopsidae Panesar, 2004 ** Family Stygotoniidae Cook, 1992 ** Family Sperchontidae Thor, 1900 ** Family Rutripalpidae Sokolow, 1934 ** Family Teutonidae Koenike, 1910 ** Family Anisitsiellidae Koenike, 1910 ** Family Lebertiidae Thor, 1900 ** Family Acucapitidae Wiles, 1996 ** Family Oxidae Viets, 1926 ** Family Torrenticolidae Piersig, 1902 * Superfamily

Hygrobatoidea Hygrobatoidea is a superfamily of water mites found in North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the e ...

Koch, 1842 ** Family Pontarachnidae Koenike, 1910 ** Family Limnesiidae Thor, 1900 ** Family Omartacaridae Cook, 1963 ** Family Wettinidae Cook, 1956 ** Family Frontipodopsidae Viets, 1931 ** Family Ferradasiidae Cook, 1980 ** Family Lethaxonidae Cook, Smith & Harvey, 2000 ** Family Hygrobatidae Koch, 1842 ** Family Aturidae Thor, 1900 ** Family Feltriidae Viets, 1926 ** Family

Unionicolidae Unionicolidae is a family of prostigs in the order Trombidiformes. There are about 5 genera and at least 40 described species in Unionicolidae. Genera * '' Huitfeldtia'' Thor, 1898 * '' Koenikea'' Wolcott, 1900 * '' Najadicola'' Piersig, 1897 * ' ...

Oudemans, 1909 ** Family Pionidae Thor, 1900 ** Family Astacocrotonidae Thor, 1927 * Superfamily Arrenuroidea Thor, 1900 ** Family Momoniidae Viets, 1926 ** Family Nudomideopsidae Smith, 1990 ** Family Mideopsidae Koenike, 1910 ** Family Athienemanniidae Viets, 1922 ** Family Chappuisididae Motas & Tanasachi, 1946 ** Family Gretacaridae Viets, 1978 ** Family Neoacaridae Motas & Tanasachi, 1947 ** Family Mideidae Thor, 1911 ** Family Acalyptonotidae Walter, 1911 ** Family Kantacaridae Imamura, 1959 ** Family Nipponacaridae Imamura, 1959 ** Family Harpagopalpidae Viets, 1924 ** Family Arenohydracaridae Cook, 1974 ** Family Amoenacaridae Smith & Cook, 1997 ** Family Laversiidae Cook, 1955 ** Family Krendowskiidae Viets, 1926 ** Family Arrenuridae Thor, 1900 ** Family Bogatiidae Motas & Tanasachi, 1948 ** Family Hungarohydracaridae Motas & Tanasachi, 1959 ** Family Uchidastygacaridae Imamura, 1956 * Superfamily Stygothrombidioidea Thor, 1935 (1 family) ** Family Stygothrombiidae Thor, 1935

References

{{Taxonbar, from=Q7135940 Trombidiformes