Endeostigmata

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Taxonomy

Micropsammidae Coineau & Theron, 1983

Diagnosis

Elongate endeostigmatans without prodorsal trichobothria, but with postpedal constrictions and massive chelicerae.

Remarks

Micropsammus, an elongate mite with a strong constriction behind legs IV, is the least aberrant of the Nematalycoidea and retains 3 pairs of prodorsal setaeseta:
(pl. setae, from L. = bristle) cuticular process composed of a hollow shaft (sometimes filled with a refractive material) produced from a membranous socket (the alveolus); the hair-like, spine-like, branched or variously expanded structures on the surfaces of the legs and body.  Most setae function as mechanoreceptors, but others (e.g., solenidia) are chemoreceptors or have unknown or ambiguous functions.
, a naso bearing setae ro, and well developed rutellarutellum:
(pl. rutella) In Sarcoptiformes, the hypertrophied setae on the hypostome, often toothed; not to be confused with a corniculus (although possibly a homologue).  In Astigmata, the rutellum may be referred to as a pseudorutellum, although it is the same structure.  Various forms of rutella are recognized, including the atelebasic and pantelebasic.
. Species of Micropsammus feed on fungi and form gut boluses, but nothing is known about the other members of the cohort except that they appear to be fluid feeders.

References

• Coineau and Theron 1983Coineau and Theron 1983:
  Coineau Y, Theron P. 1983. Les Micropsammidae, n. fam. d’Acariens Endeostigmata des sables fin. Acarologia 24: 275–280.
• Kethley 1990aKethley 1990a:
  Kethley JB. 1990a. Acarina: Prostigmata (Actinedida). pp. 667–756. In: Dindal DL, ed. Soil biology guide. John Wiley & Sons, Brisbane.