Enarthronotides (Enarthronota, Arthronotina)

Superorder Acariformes

   Order Sarcoptiformes

      Suborder Oribatida

          Supercohort Enarthronotides  – Hypochthonidea, Protoplophoroidea, Brachychthonoidea, Atopochthonoidea, Lohmannoidea.

Common names: enarthronote oribatid mites

Probability of Encounter: low

Quarantine importance: No known quarantine importance.  Most species are small to minute fungivores in mostly dry soils, including house dust and rarely stored products.

Diagnosis.  White to yellow, tan, brown, or rarely more brightly coloured armoured oribatid mites with 1-3 hysterosomal scissures, or their remnants, or pytchoidy.  Pedofossae sometimes present.  Bodies rectangular, elongate, oval or globular; opisthosomal glands absent.  Setae ranging from setiform, to brush-like, to highly modified leaf-like shapes or ornate dendritic arrangements.  Capitulum usually withdrawn into a camerostome; chelicerae sometimes visible from above; a pair of lateral eyes rarely present.  Macropyline, 3 pairs of genital papillae.

Similar taxa.  Some Endeostigmata somewhat resemble enarthronotes, but are soft-bodied and lack scissures (although remnants of primary segmentation may be present).

Ecology & Distribution. Fossil enarthronotes are known from the Devonian.  Extant taxa are found in most soil types, but are especially abundant in the drier soils and in mosses.  Many species are all female parthenogens.  The feeding ecology of this group is poorly understood, but many have highly modified chelicerae, cheliceral setae, and adoral setae.  Brachychthonioids are found everywhere, usually in high diversity, feed on algae and other microbes, and are among the smallest of all oribatid mites.  Hypochthonioids are generally dorsoventrally flattened, but Mesoplophoridae are globular, lack any scissures, and exhibit ptychoidy.  Protoplophoroids range from poorly sclerotised endeostigmatan-like mites (e.g. Paralycus), to rather brachythonioid-like mites (e.g. Haplochthonius), to strongly ornamented mites with elongate erectile setae (e.g. Cosmochthonius), to light-bulb shaped sub-ptychoid mites (e.g. Sphaerochthonius), to fully ptychoid taxa (e.g. Protoplophora). 

References

Balogh, J. and Balogh, P. 1987. A new outline of the family Lohmanniidae Berlese, 1916 (Acari, Oribatei). Acta Zoologica Hungarica 33: 327-398.

Balogh J & Mahunka S.  1985.  Primitive Oribatids of the Palaearctic Region.  Elsevier: Amsterdam.

Colloff M & Halliday B.  1998.  Oribatid Mites.  A Catalogue of Australian Genera and Species.  Monograph on Invertebrate Taxonomy Vol. 6.  CSIRO Publications: Melbourne.

Gilyarov MS & Krivolutsky DA (eds)  1975.  Handbook for the Identification of Soil-inhabiting Mites, Sarcoptiformes.  Zoological Institute of the Academy of Sciences: Petrograd [In Russian]

Hunt G, Colloff MJ, Dallwitz M, Kelly J. & Walter DE.  1998.  An Interactive Key to the Oribatid Mites of Australia.  CSIRO Publishing, Collingwood, Victoria.  (Compact Disk and User Guide).

Lee DC. 1982. Sarcoptiformes (Acari) of South Australian soils. 3. Arthronotina (Cryptostigmata). Records of the South Australian Museum 18: 327-359.

Norton, R. A. 1975.  Elliptochthoniidae, a new mite family (Acarina: Oribatei) from mineral soil in California. J. New York Entomol. Soc. 83: 209-216.

Norton, R. A. 1982.  Arborichthonius n. gen., an unusual enarthronote soil mite (Acarina: Oribatei) from Ontario. Proc. Entomol. Soc. Wash. 84: 85-96.

Norton, R. A. 1984a. Monophyletic groups in the Enarthronota (Sarcoptiformes). In: (D. A. Griffiths and C. E. Bowman, eds.). Acarology VI, vol. 1. Ellis Horwood, Chichester: 233-240.

Norton, R. A. 2001. Systematic relationships of Nothrolohmanniidae, and the evolutionary plasticity of body form in Enarthronota (Acari: Oribatida). In: (R.B. Halliday, D.E. Walter, H.C. Proctor, R.A. Norton and M.J. Colloff, eds.). Acarology: Proc.10th Internat. Congr., Canberra.  CSIRO Publishing, Melbourne: 58-75.

Schatz, H. 2003.  New Sphaerochthonius species from the Neotropical region (Acari: Oribatida).  Rev. Suisse Zool. 110: 111-124.