Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

• Phytoseioidea with entire or shallowly incised dorsal shields usually bearing >25 (rarely 22) pairs of setae, mostly tricarinate in form
• Anterior hypostomal and trochanteral setae not elongate or whip-like
• Corniculi well spaced and horn-like
• Median lobe of pulvillus of legs II–IV rounded
• Femur I (12 setae) and femur II (11 setae) with seta v3
• Paranal setae inserted anterior to hind margin of anal opening

More about Lasioseius on Bee Mite ID

Similar taxa

Species of Aceodromus are highly hypotrichous, with 11 pairs of setae on the podonotal region and 7–10 pairs on the opisthonotal region. Species of Blattisocius have few teeth on the fixed digit, simple dorsal shield setae, and approximate corniculi. Ologamasidae have sternal shields with 4 pairs of setae. Laelapidae usually have an anal shield and a flask-, tongue-, dagger-shaped or otherwise highly modified genital or opisthogenital shield. Ameroseiidae lack setae J5. Most Phytoseiidae have 21 or fewer pairs of dorsal shield setae. Podocinidae have long, whip-like legs I. Macrochelidae usually have recurved peritremes. Halolaelapidae  have a 3-tined palp apotele. Species of Zygoseius (Pachylaelapidae) have the metasternal shield fused to endopodal elements.

Key to genera of Blattisociidae

1. Leg II of female often thickened, with strong, opposable spine-like setae on ventral surface on femur, genu, tibia, and tarsus; fixed chela multidentate, its distal extremity usually with enlarged rounded margin bearing a row of small rasping teeth; trochanter I with 4 or 5 setae (av1 absent); genu and tibia I each with maximum of 11 setae (pd3, av2 absent).............................. Hoploseius
   - Leg II of female not thickened, without spine-like ventral setae; fixed chela with few to many teeth, its distal extremity not enlarged, without row of small teeth; trochanter I with 6 setae (av1 present); genu and tibia I each with 13 (rarely 12) setae (pd3 and usually av2 present).............................. 2

2. Corniculi narrowly separated, usually slender; epistome convex, smooth; fixed chela with few or no teeth; peritrematal shield slender, barely wider than stigma at level of stigma; female with humeral seta (r3) usually on soft cuticle beside dorsal shield; protonymph with 2 setae on palp trochanter.............................. 3
   - Corniculi well separated, stout; epistome convex or triramous, smooth or denticulate; fixed chela usually with many teeth; peritrematal shield clearly wider than diameter of stigma at level of stigma; female with humeral setae on dorsal shield; protonymph with 1 seta on palp trochanter.............................. 4

3. Dorsal shield without midlateral incisions; opisthonotal region of dorsal shield holotrichous, with 15 pairs of setae; fixed chela well developed or reduced; female without isolated metasternal plates; male leg IV without enlarged, spine-like setae.............................. Blattisocius
   - Dorsal shield with midlateral incisions; opisthonotal region of dorsal shield hypotrichous, with 12 pairs of setae (lacking a pair in each of J, Z, S series); fixed chela well developed; female with isolated metasternal plates; male leg IV with several enlarged spine-like setae.............................. Adhaerenseius

4. Female and male with all marginal r–R setae on edge of dorsal shield, opisthonotal region of shield with 20 pairs of setae; rows of deutosternal denticles narrow, each with 2–4 denticles; movable chela with ridge extending from para-axial surface to 1–2 denticles on proximo-ventral surface.............................. Orthadenella
   - Female and male with 1–9 pairs of marginal r–R setae on soft cuticle beside dorsal shield, opisthonotal region of shield with maximum of 15 pairs of setae in female, 17 in male; rows of deutosternal denticles moderately wide, each with 5 to many denticles; movable chela lacking ridge or denticles on paraxial and ventral surface.............................. 5

5. Adults with 1 pair of marginal setae (R1) on soft lateral cuticle; female metapodal plates incorporated into ventrianal or peritrematal plates, and ventrianal shield with 7 pairs of setae in addition to circumanals; male with holoventral shield.............................. 6
   - Adults with 3–9 pairs of marginal setae (r–R) on soft lateral cuticle; female metapodal plates free on soft cuticle, and ventrianal shield with 6 or fewer pairs of setae in addition to circumanals; male usually with separate sternogenital, ventrianal and peritrematal-exopodal shields.............................. 7

6. Podonotal region of adult dorsal shield lacking setae z1, s1, s2; female with metapodal plates incorporated into ventrianal shield; female ventrianal shield lacking setae ZV1 but with JV5 on its posterolateral margins; genu III with 10, tibiae III and IV with 9 and 10 setae, respectively (pl–2 present on each of these segments).............................. Zercoseius
   - Podonotal region of adult dorsal shield holotrichous; female with metapodal plates incorporated into posterior margins of peritrematal shields; female ventrianal shield with setae ZV1 but with JV5 inserted on soft cuticle behind its posterolateral margins; genu III with 9, tibiae III and IV with 8 and 9 setae, respectively (pl–2 absent from each of these segments).............................. Arrhenoseius

7. Female with 11 pairs of setae on podonotal region of dorsal shield (s5 absent) and 7–10 pairs of setae on opisthonotal region (Z1, J2 absent); epigynial shield rounded posteriorly; ventral setae ZV1, JV5 absent; cervix of spermatheca not sclerotized; movable chela with 4 teeth; genua II and III with 10 and 8 setae respectively (pv1 absent).............................. Aceodromus
   - Female with 12–23 pairs of setae on podonotal region of dorsal shield (s5 present) and 10–15 pairs of setae on opisthonotal region (Z1, J2 present); epigynial shield usually truncate posteriorly; ventral setae ZV1, JV5 present; cervix of spermatheca well sclerotised; movable chela with 3 teeth (rarely 4); genua II and III usually with 11 and 9 setae respectively (pv1 usually present).............................. Lasioseius

Ecology and distribution

Species of Lasioseius are common in many habitats, including vegetation, flowers and in association with insects. More than 100 species are known.

References

• Evans and Till 1979Evans and Till 1979:
  Evans EO, Till WM. 1979. Mesostigmatic mites of Britain and Ireland (Chelicerata: Acari-Parasitiformes): An introduction to their external morphology and classification. Transactions of the Zoological Society of London 35 (2): 145–270.
• Halliday et al. 1998Halliday et al. 1998:
  Halliday RB, Walter DE, Lindquist EE. 1998. Revision of the Australian Ascidae (Acarina: Mesostigmata). Invertebrate Taxonomy 12: 1–54.
• Karg 1993Karg 1993:
  Karg W. 1993. Acari (Acarina), Milben Parasitiformes (Anactinochaeta) Cohors Gamasina Leach, Raubmilben. Die Tierwelt Deutschlands 59: 1–523.
• Krantz 1962Krantz 1962:
  Krantz GW. 1962. Acari. Free-living Mesostigmata. II. The family Aceosejidae. Parc National de la Garamba - Mission H. de Saeger 34: 3–29.
• Krantz 1986Krantz 1986:
  Krantz GW. 1986. A manual of acarology [2nd ed., emended 1986]. Oregon State University Book Stores, Corvallis.
• Krantz and Ainscough 1990Krantz and Ainscough 1990:
  Krantz GW, Ainscough B. 1990. Mesostigmata. pp. 583–665. In: Dindal DL, ed. Soil biology guide. John Wiley & Sons, Brisbane.
• Lindquist and Chant 1964Lindquist and Chant 1964:
  Lindquist EE, Chant DA. 1964. A redescription of Aceodromus Muma and its transfer to the Blattisociinae (Acarina: Blattisociidae). The Canadian Entomologist 96: 500–7.
• Lindquist and Evans 1965Lindquist and Evans 1965:
  Lindquist EE, Evans GO. 1965. Taxonomic concepts in the Ascidae, with a modified setal nomenclature for the idiosoma of the Gamasina (Acarina: Mesostigmata). Memoirs of the Entomological Society of Canada 47: 1–64
• Lindquist and Walter 1989Lindquist and Walter 1989:
  Lindquist EE, Walter DE. 1989. Biology and description of Antennoseius janus, new species (Mesostigmata: Ascidae), a mesostigmatic mite exhibiting adult female dimorphism. Canadian Journal of Zoology 67: 1291–1310.
• McGraw and Farrier 1969McGraw and Farrier 1969:
  McGraw JR, Farrier MH. 1969. Of the superfamily Parasitoidea (Acarina: Mesostigmata) associated with Dendroctonus and Ips (Coleoptera: Scolytidae). North Carolina Agricultural Experiment Station Technical Bulletin No. 192, 162 pp.
• Walter 1998aWalter 1998a:
  Walter DE. 1998a. Ectoantennoseius kitchingi, n. gen., n. sp. (Acari: Mesostigmata: Ascidae) from the rainforest canopy in Australia and a cladistic hypothesis about its relationships. International Journal of Acarology 24: 45–51.
• Walter and Ikonen 1989Walter and Ikonen 1989:
  Walter DE, Ikonen EK. 1989. Species, guilds and functional groups: Taxonomy and behavior in nematophagous arthropods. Journal of Nematology 21: 315–327.
• Walter and Lindquist 1989Walter and Lindquist 1989:
  Walter DE, Lindquist EE. 1989. Life history and behavior of ascid mites in the genus Lasioseius (Acari: Mesostigmata) from grassland soils in Colorado with taxonomic notes and a description of new species. Canadian Journal of Zoology 67: 2797–2813.
• Walter and Lindquist 1995Walter and Lindquist 1995:
  Walter DE, Lindquist EE. 1995. The distribution of asexual ascid mites (Acari: Parasitiformes) does not support the biotic uncertainty hypothesis. Experimental and Applied Acarology 19: 423–442.
• Walter and Lindquist 1997Walter and Lindquist 1997:
  Walter DE, Lindquist EE. 1997. Australian species of Lasioseius (Acari: Mesostigmata: Ascidae): the porulosus group and other species from rainforest canopies. Invertebrate Taxonomy 11: 525–547.
• Walter and Lindquist 2000Walter and Lindquist 2000:
  Walter DE, Lindquist EE. 2000. Arrhenoseius gloriosus n. g., n. sp. (Acari: Mesostigmata: Ascidae), an arrhenotokous mite from rainforests in Queensland, Australia. Acarologia 41: 53–68.