Mesostigmata

t

Taxonomy

updated 2025

Diagnostic characters

• Dorsaldorsal:
  relating to the upper or back side; opposed to ventral.
  shield divided
• Seta z5 simplesimple:
  unadorned; simple setae are needle-like and without hairs or pectins.
  or stout and distally pilosepilose:
  with a covering of hairs or hair-like processes.
  
• Intercoxal shield with granular transverse band between setae st1–2
• Fixed cheliceralcheliceral:
  of or pertaining to the chelicera.
  digit usually with membranous excrescenceexcrescence:
  (1) a brush-like, dendritic or otherwise elaborated processes produced from openings in the movable digit in trigynaspid and some microgyniine Mesostigmata; (2) an encrusted covering or outgrowth-like structure. 
  

Key to some Poecilochirus deutonymphs (after Hyatt 1980)

1. Dark band transverse between setae st1–2 not extending posteriorly.............................. 2
   -  Dark band extending along postero-lateral margins of intercoxal shield.............................. 3

2. Most podonotal shieldpodonotal shield:
   the anterior shield in mesostigmatans with divided dorsal shields.  
   setae (except r3, z5) relatively short, not reaching next seta in series.............................. P. davydovae Hyatt
   - Most podonotal shieldpodonotal shield:
   the anterior shield in mesostigmatans with divided dorsal shields.  
   setae long.............................. P. subterraneus (Mueller)

3. Membranous process on fixed digitfixed digit:
   the distal extension of the middle article of the chelicera; usually bearing teeth and a distal hook and opposed to the movable digit in chelate-dentate forms, but often regressed; in Mesostigmata the fixed digit may bear the pilus dentilis.
   elongate, bifurcatebifurcate:
   split into two distally or with two projections. 
   .............................. P. carabi G. & R. Canestrini
   - Membranous process on fixed digitfixed digit:
   the distal extension of the middle article of the chelicera; usually bearing teeth and a distal hook and opposed to the movable digit in chelate-dentate forms, but often regressed; in Mesostigmata the fixed digit may bear the pilus dentilis.
   rudimentary.............................. P. austroasiaticus Vitzthum

Ecology and distribution

These mites are phoretic on carrion beetles (Silphidae) and feed on nematodes and mites on the carcasses that the beetles utilize as food. Poecilochirus carabi G. & R. Canestrini is rarely found on carabid or dung beetles.

References

• Hyatt 1980Hyatt 1980:
  Hyatt KH. 1980. Mites of the subfamily Parasitinae (Mesostigmata: Parasitidae) in the British Isles. Bulletin of the British Museum (Natural History) Zoology 38: 237-378.
• Schwarz and Müller 1992Schwarz and Müller 1992:
  Schwarz HH and Müller JK. 1992. The dispersal behaviour of the phoretic mite Poecilochirus carabi (Mesostigmata, Parasitidae): Adaptation to the breeding biology of its carrier Necrophorus vespilloides (Coleoptera, Silphidae). Oecologia 89: 487-493.
• Springett 1968Springett 1968:
  Springett BP. 1968. Aspects of the relationship between burying beetles, Necrophorus spp. and the mite, Poecilochirus necrophori Vitz. Journal of Animal Ecology 37: 417-424.