Onchodellus, Berlese, 1904

Zhang, Xue-Song, Guo, Jian-Jun, Yi, Tian-Ci & Jin, Dao-Chao, 2020, Two new species of the genus Onchodellus (Acari: Pachylaelapidae) from China, Zootaxa 4801 (3), pp. 450-460 : 459

Key to Chinese species of the genus Onchodellus (females)

1. Larger species (length more than 700 μm, width more than 460 μm)............................................ 2

– Smaller species (length less than 700 μm, width less than 460 μm).............................................. 5

2. Lateral and opisthogastric soft integument with more than ten pairs of setae; edge of metapodal shield smooth........... 3

– Lateral and opisthogastric soft integument with less than nine pairs of setae; outer edge of metapodal shield with fine teeth; anal shield length/width ratio: 1:1.50..................................... Onchodellus xizangensis (Ma & Wang), 1997

3. Deutosternal groove with seven rows of denticles; setae on dorsal shields short and small, movable digit and fixed digit each with one tooth................................................. Onchodellus brevisetosus Gu, Huang & Li, 1991

– Deutosternal groove with six rows of denticles............................................................. 4

4. Anterior end of idiosoma strongly extended forward; outer edge of peritremes beside coxae II serrated; leg II with four spur-like setae; anal shield length/width ratio: 0.35–0.42.................... Onchodellus quattuorspinous Zhang & Jin , sp. nov.

– Anterior end of idiosoma normal; outer edge of peritremes smooth entirely; leg II with one spur-like setae; anal shield length/ width ratio: 1:1.75....................................................... … Onchodellus gansuensis Ma, 1985

5. Dorsal shield with 27 pairs of setae; metapodal shield rectangle in shape..... Onchodellus quadritus Gu, Huang & Li, 1991

– Dorsal shield with 30 pairs of setae; metapodal shield in various shape but not rectangle............................ 6

6. Epistome tip extended in a shape of inverted “V”; dorsal shieldlength/width ratio: 1.29–1.39; metapodal shield absent................................................................... Onchodellus menglaensis Zhang & Jin , sp. nov.

– Epistome tip not in a inverted “V”, with strong apical serration................................................. 7

7. Inner tooth of cheliceral movable digit and fixed digit on remote end; anterior margin of anal shield overlapped by posterior margin of genitiventral shield............................................... Onchodellus xinghaiensis Ma, 1985

– Cheliceral movable digit and fixed digit medial teeth near the end; anterior margin of anal shield separated from posterior margin of genitiventral shield.............................................................................. 8

8. Epistome top ten dentate projections; coxa I sub-terminally with a verrucous projection; j1, z1, and J5 almost equal in length and as long as j2 ................................................. Onchodellus torocoxus Gu, Huang & Li,1991

– Epistome top 11 dentate projections; coxa I without a verrucous projection; j1, z1, and J5 shorter than all other dorsal setae............................................................ Onchodellus tsengyihsiungi Ma, Ho & Wang, 2008