Opilioacaridae is the sole family 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 in the order Opilioacarida, made up of about 13 genera. The mites of this family are rare, large (1.5 to 2.5 mm) mites, and are widely considered primitive, as they retain six pairs of eyes, and abdominal segmentation. They have historically been considered separate from other mites belonging to

Acariformes The Acariformes, also known as the Actinotrichida, are the most diverse of the two superorders of mites. Over 32,000 described species are found in 351 families, with an estimated total of 440,000 to 929,000 species, including undescribed species ...

and

Parasitiformes Parasitiformes are a superorder of Arachnids, constituting one of the two major groups of mites, alongside Acariformes. Parasitiformes has, at times, been classified at the rank of order or suborder. It is uncertain whether Parasitiformes and A ...

, but are now generally considered a subgroup of Parasitiformes based on

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

. The first member of the Opilioacarida to be discovered was the

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

n species '' Opilioacarus segmentatus'', which was described by

Carl Johannes With Carl Johannes With (December 11, 1877 – June 16, 1923) was a Danish doctor and arachnologist, specialising in pseudoscorpions and mites. With was born in Lemvig to Nicolai Rasmus With and his wife Rasmine Sophie Dorothea With, but was orphaned b ...

in 1902, followed by the Sicilian '' Eucarus italicus'' and '' Eucarus arabicus'' from

Aden Aden ( ar, عدن ' Yemeni: ) is a city, and since 2015, the temporary capital of Yemen, near the eastern approach to the Red Sea (the Gulf of Aden), some east of the strait Bab-el-Mandeb. Its population is approximately 800,000 people. ...

, both in 1904. Two

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

specimens are known, one of which was discovered in

Baltic amber The Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that these forests created more than 1 ...

from the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

, while the other one was discovered in the

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

(

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

) around 99 million years old, tentatively assigned to the living genus '' Opilioacarus.'' Members of the group live in semi-arid and tropical environments in leaf-litter, under rocks and in caves. Their diet is known to include arthropod carcasses, fungal spores, and pollen.

Genera

These 13 genera belong to the family Opilioacaridae: * '' Adenacarus'' Hammen, 1966 * '' Amazonacarus'' Vázquez, Araújo & Feres, 2014 * '' Brasilacarus'' Vázquez, Araújo & Feres, 2015 * '' Caribeacarus'' Vázquez & Klompen, 2009 * '' Indiacarus'' Das & Bastawade, 2007 * '' Neocarus'' Chamberlin & Mulaik, 1942 * '' Opilioacarus'' With, 1902 * '' Panchaetes'' Naudo, 1963 * '' Paracarus'' Chamberlin & Mulaik, 1942 * '' Phalangiacarus'' Coineau & Hammen, 1979 * '' Salfacarus'' Hammen, 1977 * '' Siamacarus'' Leclerc, 1989 * '' Vanderhammenacarus'' Leclerc, 1989

References

External links

* {{Taxonbar, from1=Q136926, from2=Q14849555 Acari taxonomy Arachnid orders Monotypic arthropod taxa