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Zygoseius

Family: Pachylaelapidae Berlese (pars)

Zygoseius Berlese

Diagnostic characters:

• Adults with holodorsal shield lacking seta J3

• Subcordate ventrianal shield with 13 setae (ZV1-2, JV1-3 + circumanals)

• Genital shield truncate posteriorly and bearing 1 pair of setae

• Sternal shield with 3 pairs of setae and convex posterior margin

• Metasternal setae on metasternal-endopodal shield that is fused anteriorly to sternal shield

• Peritrematal shield extending beyond coxae IV

• Arthrodial brush vestigial

• Palp apotele with 3-tines; tibia I with 6 dorsal setae; tibia III with 8 dorsal setae; tibia IV with 8 dorsal setae.

Species: Zygoseius furciger (Berlese) 1916 (= Z. badrii Hafez and Nasr, 1982); Z. sarcinulus Halliday 1997 (Australia); Z. ampullus Halliday (Argentina); Z. metoecus Halliday (Argentina).  [NB - Z. alter Vitzthum, Z. vithzthumi Westerboer, and Z. tectus Hyatt all = Lasioseius.]

Similar taxa.  Species of Pachyseius have spurs on tarsi II and have st4 on a metasternal shield or in the soft cuticle.  Species of Macrocheles have recurved peritremes.  Ascid mites lack metasternal-endopodal shields.  Some hypoaspidine Laelapidae have a metasternal-endopodal shield, but have anal, rather than ventrianal shields.

Simplified Key to Common Genera of Pachylaelapidae

1.  Females (and usually males) with spur-like distal setae on tarsus II ..... 3

  - Spur-like setae on tarsus II absent ..... 2

2.  Female with subcordate ventrianal shield with 13 setae (ZV1-2, JV1-3 + circumanals); genital shield truncate posteriorly and bearing 1 pair of setae; sternal shield with 3 pairs of setae and convex posterior margin; metasternal setae on metasternal-endopodal shield; free-living or on dung beetles ..... Zygoseius

  - Female with anal shield (rarely capturing 1-2 ventral setae); opisthogenital shield spreading laterally, with 2 pairs of setae and recurved posterior margin; associated with ants ..... Sphaerolaelaps

3.  Female sternal shield bearing 4 pairs of setae, opisthogenital shield with 2 or more pairs of setae, and anal shield with 3 circumanal setae ..... 5

  - Female sternal shield bearing 3 pairs of setae (st4 on small metasternal shield or in soft cuticle), genital shield with 1 pair of seta, and ventrianal shield with 7-10 setae ..... Pachyseius

5.  Tibia I with 5 dorsal setae; palp apotele 3-tined ..... 5

  -  Tibia I with 6 dorsal setae; palp apotele 2-tined ..... 6

5.  Genu I with 5 dorsal setae ..... Onchodellus

  - Genu I with 6 dorsal setae ..... Pachylaelaps

6.  Seta st4 on small metasternal plate; dorsal shield with 37 pairs of setae ..... Pachyseiulus

  -  Seta st4 on in soft cuticle; dorsal shield with 35 pairs of setae ..... Pseudopachyseiulus

References

Halliday RB. 1997. Revision of the genus Zygoseius Berlese (Acarina: Pachylaelapidae). Acarologia 38: 3-20.