Steatonyssus, Kolenati, 1858

Orlova, Maria V. & Anisimov, Nikolay V., 2023, Three new species of bat-parasitic gamasid mites of the genera Spinturnix, Macronyssus and Steatonyssus (Acari: Mesostigmata: Spinturnicidae, Macronyssidae) from Siberia and Mongolia, with keys to species of Russia and adjacent countries, Persian Journal of Acarology 12 (2), pp. 211-239 : 231-232

Key to species of the genus Steatonyssus of Russia and adjacent countries (males)

1. Ventral sclerotization undivided ................................................................................................... 3

– Ventral sclerotization divided ....................................................................................................... 2

2. Setae St4 situated on unsclerotized cuticle, idiosoma with 10-15 dorsal and eight ventral pairs of setae ........................................................................................... S. pseudoheteroventralis sp. nov.

– St4 situated on sternogenitoventral shield, idiosoma with 25 dorsal and 13 ventral pairs of setae. .............................................................................................................................. S. heteroventralis

3. Two dorsal plates .......................................................................................................... S. superans

– Single dorsal plate ......................................................................................................................... 4

4. Setae Z5 long ................................................................................................................................. 5

– Setae Z5 short ................................................................................................................................ 6

5. Dorsal plate with 23–24 pairs of setae; holoventral plate slightly widens posteriorly to coxae IV; anterior seta on coxae III resembles a fish tail .............................................................. S. spinosus

– Dorsal plate with 25 pairs of setae; holoventral plate narrow, without widening posteriorly to coxae IV; anterior seta on coxae III usual ................................................................................ S. noctulus

6. Peritremes reaching middle of coxae III ....................................................................................... 7

– Peritremes reaching anterior margins of coxae III or posterior margins of coxae II .................... 8

7. Dorsal plate with 18 pairs of setae; anterior seta on coxa III usual ............................. S. desertorus

– Dorsal plate with 19 pairs of setae; anterior seta on coxae III variable ........................................ 6

8. Anterior seta on coxa is III spur-like, with ridge-like thickening .................. S. occidentalis evansi

– Anterior seta on coxa III usual ...................................................................................................... 9

9. Dorsal plate clearly divided into podosomal and opisthosomal parts, these parts closely connected by a transverse furrow ................................................................................................ S. mongolicus

– Dorsal plate undivided ................................................................................................................ 10

10. Dorsal plate with 16 pairs of setae; anterior seta on coxae III usual …………………..…. S. cavus

– Dorsal plate with 19–20 pairs of setae; anterior seta on coxae III looks like a fish tail ................ .............................................................................................................................. S. periblepharus