Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

• Both setae z3 and s6 suppressed (Amblyseiinae)
• Dorsaldorsal:
  relating to the upper or back side; opposed to ventral.
  shield strongly sclerotized, dark brown, and bearing 19 pairs of mostly minute (except j1, Z5) 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.
  , including r3 and R1
• Ventral shieldventral shield:
  in Mesostigmata, any shield or shields in the ventral region; often fused with the anal shield to form a ventrianal shield. [Back to Top]
  present and bearing 3 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.
  
• Anal shield with irregular anterior margin

Similar taxa

Phytoseiinae and Typhlodrominae have either or both 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.
z3 and s6. The most similar Amblyseiinae are members of the genus Euseius, but they are not as heavily sclerotized and brown in color and they have an entireentire:
a shield or sclerite with a continuous margin without incisions.
(typically vase-shaped) ventrianal shieldventrianal shield:
in Mesostigmata, a ventral shield bearing the anal opening, circum anal setae, and one or more pairs of ventral setae or pores (lyrifissures) [see anal shield]; maybe rather narrow or very broad and covering most of the gaster.
. Some individuals of Ricoseius loxocheles De Leon have a narrowly divided ventrianal shieldventrianal shield:
in Mesostigmata, a ventral shield bearing the anal opening, circum anal setae, and one or more pairs of ventral setae or pores (lyrifissures) [see anal shield]; maybe rather narrow or very broad and covering most of the gaster.
, but they also have mostly very long 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 3 pairs of r–R (r3, r5, R1) 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.
in the soft cuticle alongside the shield.

Ecology and distribution

Iphiseius degenerans may have originated in Africa but is used in biological control and is now found in many parts of the world.

References

• Athias-Henriot 1957Athias-Henriot 1957:
  Athias-Henriot C. 1957. Phytoseiidae et Aceosejidae (Acarina: Gamasina) d'Algérie. I. Genres Blattisocius Keegan, Iphoseius Berlese, Amblyseius Berlese, Phytoseius Ribaga, Phytoseiulus Evans. Bulletin de la Société d'Histoire Naturelle de l'Afrique du Nord 48: 319–352.
• Chant and McMurtry 2005Chant and McMurtry 2005:
  Chant DA, McMurtry JA. 2005. A review of the subfamily Amblyseiinae Muma (Acari: Phytoseiidae): Part VI. The tribe Euseiini n. tribe, subtribes Typhlodromalina n. subtribe, Euseiina n. subtribe, and Ricoseiina n. subtribe. International Journal of Acarology 31: 187–224.
• El-Badry 1968El-Badry 1968:
  El-Badry EM. 1968. On a new predatory mite of economic significance from the Sudan (Acarina: Phytoseiidae). Acarologia 10: 432-436.
• Pritchard and Baker 1963Pritchard and Baker 1963:
  Pritchard EA and Baker EW. 1963. Mites of the family Phytoseiidae from Central Africa, with remarks on the genera of the world. Hilgardia 33: 205-309.
• Tseng 1976Tseng 1976:
  Tseng YH. 1976. Systematics of the mite family Phytoseiidae from Taiwan, with a revised key to the genera of the world (II). Journal of the Agricultural Association of China 94: 86-128.