Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

• Chelicera with well developed arthrodial brush
• Peritreme linear
• Free-living, not phoretic on insects

Diagnosis

Yellow to dark brown dermanyssine mesostigmatans with holodorsal shields. Peritremes generally well developed, shields sometimes produced posteriorly. Sternal shield bearing 3 (rarely 4) pairs of setae (st1–3, 4) and 2–3 pairs of lyrifissures; metasternal shields present with st4 or fused to sternal or endopodal shields; genital shield mound-shaped, tongue-shaped, or broadly opisthogenital and bearing 1–2 (rarely more) pair of setae; ventrianal shield broad with several pairs of ventral setae, sometimes fused to genital shields. Tarsus I with or without claws; trochanter I with 6 setae; tibia I with 5/3 dorsal/ ventral setae, genu I 5/2–3; genu IV with 9 setae, 4/1 dorsal/ ventral. Chelicerae chelate-dentate, serrate, or snapping; movable digit without excrescences, but with well developed arthrodial brush. Palp genu with 6 setae, palp apotele 3-tined; corniculi horn-like to bayonet-like. Tritosternum biflagellate with columnar base. Tectum with long median process or denticulate-trifurcate. Female sperm induction pores near bases of coxae IV.  Males with genital opening at base of tritosternum in sternogenital shield; spermatodactyl usually well developed.

Similar taxa

Macrochelids (recurved peritreme); pachylaelapids (lack arthrodial brush); Ologamasidae (tibia I with 6 dorsal setae); Laelapidae: Ololaelaps (lacks arthrodial brush).

References

• Evans 1956Evans 1956:
  Evans GO. 1956. On the classification of the family Macrochelidae with particular reference to the subfamily Parholaspinae (Acarina - Mesostigmata). Proceedings of the Zoological Society of London 127: 345–377.
• Halliday 1995Halliday 1995:
  Halliday RB. 1995. A new genus and two new species of Parholaspididae from Australia and Papua New Guinea (Acarina: Mesostigmata). In: Harvey MS, ed. Australasian spiders and their relatives: Papers honouring Barbara York Main. Records of the Western Australian Museum, Supplement 52: 209–217.