''Dytiscacarus'' is a genus of trombidiform

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 that are sub-elytral parasites of diving beetles (

Dytiscidae The Dytiscidae – based on the Greek ''dytikos'' (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live ...

). It is in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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

Dytiscacaridae, and comprises three species. It has been recorded from

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkm ...

and the United States.

Morphology

The family has three distinctive features not found in other mites (

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

): the infracapitulum has a pair of gnathosomatic neostigmata on its dorsal face, the movable cheliceral stylets are sheathed and can be deeply retracted into the

prosoma The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''ce ...

, and the pretarsi of all legs lack empodia and bear paired claws strongly modified into sclerotized tenent-like structures (to attach to hosts). These features occur in all of the active life stages. Dytiscacaridae are also

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

: females have the fourth pair of legs elongated (possibly for greater mobility), while males have a caudal copulatory capsule.

Biology

Dytiscacaridae spend their life cycle under the

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs ( Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes altern ...

of Dytiscidae beetles. The eggs are laid on the inner surface of the elytra, being glued there by a gelatinous substance. It is possible, though not yet confirmed, that these mites pierce the beetle's wings with their stylets to feed on

hemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

. It is unknown how the mites disperse from beetle to beetle. It may be that like other heterostigmatan mites, adult females are the dispersants. They may be

sexually transmitted Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are spread by sexual activity, especially vaginal intercourse, anal sex, and oral sex ...

, dispersing from beetle to beetle during mating.

Species

* ''

Dytiscacarus americanus ''Dytiscacarus'' is a genus of trombidiform mites that are sub-elytral parasites of diving beetles ( Dytiscidae). It is in the monotypic family Dytiscacaridae, and comprises three species. It has been recorded from Iran and the United States. ...

'' Mortazavi and Hajiqanbar, 2018 – US. Host ''

Hydaticus bimarginatus ''Hydaticus'' is a genus of predatory water beetle belonging to the family Dytiscidae. ''Hydaticus'' can be found throughout most of the world. There are 150 described species and 12 subspecies in two subgenera in the genus ''Hydaticus''. Subge ...

'' * ''

Dytiscacarus iranicus ''Dytiscacarus'' is a genus of trombidiform mites that are sub-elytral parasites of diving beetles ( Dytiscidae). It is in the monotypic family Dytiscacaridae, and comprises three species. It has been recorded from Iran and the United States. ...

'' Mortazavi and Hajiqanbar, 2018 – Iran. Host ''

Hydaticus pictus ''Hydaticus'' is a genus of predatory water beetle belonging to the family Dytiscidae. ''Hydaticus'' can be found throughout most of the world. There are 150 described species and 12 subspecies in two subgenera in the genus ''Hydaticus''. Subg ...

'' * ''

Dytiscacarus thermonecti ''Dytiscacarus'' is a genus of Trombidiformes, trombidiform mites that are sub-elytral parasites of diving beetles (Dytiscidae). It is in the Monotypic taxon, monotypic Family (biology), family Dytiscacaridae, and comprises three species. It has ...

'' Mortazavi and Hajiqanbar, 2018 – US. Host ''

Thermonectus basillaris ''Thermonectus basillaris'' is a species of diving beetle native to the eastern United States, southern Ontario, Canada, and Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country compr ...

References

{{Taxonbar, from1=Q113163339 Raphignathoidea Parasitic acari Parasites of insects