Microtrombidiinae, Thor, 1935

Hakimitabar, Masoud & Saboori, Alireza, 2024, Notes on Atractothrombium and Fissitrombium (Acari: Trombidiformes: Microtrombidiidae) with description of a new species of Atractothrombium from Iran, Persian Journal of Acarology 13, pp. 409-425 : 421

Key to genera of Microtrombidiinae of the world with two median scuta and anterior dorsal shield with longitudinal striations (larva)

1. Tarsal claws 2-2-3 or 2-2-2 ........................................................................................................... 2

– Tarsal claws 3-3-3 ......................................................................................................................... 3

2. Tarsal claws 2-2-3, scutellum with 2 setae .............................................................. Empitrombium

– Tarsal claws 2-2-2, scutellum with 4 setae ......................................................... Lomboktrombium

3. Tarsal claws 3-3-3, deformed (with scopa, smilum and lophotrix) ............................................... 4

– Tarsal claws 3-3-3, undeformed (without scopa, smilum and lophotrix) ................................... 13

4. c 2 and d 1 plates normal (not enlarged) ...................................................................... Fissitrombium

– c 2 and d 1 plates enlarged ................................................................................................................ 5

5. Both solenidia located on the proximal or distal half of Ti I ........................................................ 6

– One solenidion located on the proximal half and the other one located on the distal half of Ti I 8

6. Both solenidia located on the proximal half of Ti I .................................................. Willmannella

– Both solenidia located on the distal half of Ti I ............................................................................ 7

7. Scutellum with longitudinal striation .............................................................. Campylothrombium

– Scutellum without longitudinal striation .............................................................. Kamitrombidium

8. Scutellum without longitudinal striation ....................................................................................... 9

– Scutellum with longitudinal striation .......................................................................................... 10

9. Scutellum with distinct and irregular reticulate pattern .................................. Camerotrombidium

– Scutellum punctate ............................................................................................. Echinothrombium

10. Scutum and scutellum with longitudinal striations confined to lateral parts ..... Trichotrombidium

– Longitudinal striations of scutum occupying its whole area ....................................................... 11

11. Longitudinal striations of scutellum few and broad ............................................. Foliotrombidium

– Longitudinal striations of scutellum numerous and fine ............................................................. 12

12. Outer claw of Ta III distally serrate, scopa and lophotrix prominent with numerous long setules, which are longer than smilum .............................................................................. Platytrombidium

– Outer claw of Ta III trifid, scopa and lophotrix small with few setules, which are shorter than smilum ............................................................................................................... Atractothrombium

13. Scutellum with ≥ 10 setae .................................................................................... Gonothrombium

– Scutellum with 2 setae ................................................................................................................. 14

14. Both solenidia located on the proximal or distal half of Ti I ...................................................... 15

– One solenidion located on the proximal half and the other one located on distal half of Ti I .... 16

15. Both solenidia located on the proximal half of Ti I, c 2 and d 1 plates enlarged, one claw at Ta III is strongly deformed (although not a typical smilum) ....................................... Trischidothrombium

– Both solenidia located on the distal half of Ti I, c 2 and d 1 plates not enlarged .. Ambilothrombium

16. c 2 and d 1 plates normal (not enlarged) .................................................................. Stirlitrombidium

– c 2 and d 1 plates enlarged .............................................................................................................. 17

17. bs barbed ............................................................................................................... Yemenitrombium

– bs truncate with distal end brush-like ............................................................................. Buandikia