Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

Typhlodrominae, Metaseiulini (setae s6 present; z3 usually present; z6, S4 and JV4 absent) with:

• s6, J2, S2, S5, JV2–3 present (+ normally present setae r3, s4, j4–6, Z4–5, J5, JV1, JV5, ZV1–2)
• z6, J1, Z1, Z3, S4 , R1, JV4 absent
• z3, ZV3 present or absent
• when present, basebase:
  the usually columnar basal part of the tritosternum; sometimes expanded and rectangular or otherwise modified; the most basal part of any structure.
  of z3 +/- aligned with and equidistant from bases z2–4
• j3 inserted near basebase:
  the usually columnar basal part of the tritosternum; sometimes expanded and rectangular or otherwise modified; the most basal part of any structure.
  of j1
• legs without macrosetae
• calyxcalyx:
  (= cervix) in phytoseioid Mesostigmata (Phytoseiidae, Blattisociidae, Otopheidomenidae, Podocinidae), a collar-like structure of the sperm access system which surrounds the base of the vesicle.
  of spermathecaspermatheca:
  a structure in the female for storing sperm, typically sac-like.
  elongate, tubular

Similar taxa

Phytoseiinae lack 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.
Z1, S2, S4 and S5. Amblyseiinae lack both 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.
z3 and s6. Ascids usually have dorsaldorsal:
relating to the upper or back side; opposed to ventral.
shields with 22 or more pairs of 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.
and only rarely (e.g., Blattisocius) have phytoseioid-like corniculicorniculus:
(pl. corniculi) (also, external malae) a usually horn-like process (sometimes toothed, bifurcate, trifurcate, spine-like, spatulate, or membranous) on the subcapitulum of parasitiform mites that usually supports the salivary styli.  A toothed corniculus could be confused with a rutellum, a possibly homologous structure in Acariformes and Opilioacarida. Phytoseiid image is spatulate corniculus.
. Within the Metaseiulini only Galendromus have 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.
R1 absent and S2 present; Galendromus (Mugidromus) species have shorter dorsal 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.
and 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.
j3 inserted well behind 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.
j1.

Ecology and distribution

Species of Galendromus are found primarily in Central America and the southern United States, but species used in biological control of spider mites (e.g., G. occidentalis) have been introduced around the world.

References

• Chant and McMurtry 1994Chant and McMurtry 1994:
  Chant DA, McMurtry JA. 1994. A review of the subfamilies Phytoseiinae and Typhlodrominae (Acari: Phytoseiidae). International Journal of Acarology 20: 223–310.
• Denmark 1982Denmark 1982:
  Denmark HA. 1982. Revision of Galendromus Muma, 1961 (Acarina: Phytoseiidae). International Journal of Acarology 8: 133-167.
• Schicha 1987Schicha 1987:
  Schicha E. 1987. Phytoseiidae of Australia and neighbouring areas. Indira Publishing House, Oak Park, Michigan.
• Schuster and Pritchard 1963Schuster and Pritchard 1963:
  Schuster RO and Pritchard EA. 1963. Phytoseiid mites of California. Hilgardia 43 (7): 191-285.