Trachygamasus, Berlese, 1906

Farahi, Sara, Shishehbor, Parviz, Nemati, Alireza & Witaliński, Wojciech, 2019, Trachygamasus karuni sp. nov., a new mite species from Iran (Parasitiformes: Parasitidae), Zootaxa 4706 (3), pp. 439-450 : 448

Key to the adults of Trachygamasus species

Females

1. Central prong of gnathotectum distally widened and bifid or trifid apically........................................ 2

- Central prong of gnathotectum acuminate, terminally pointed or rounded......................................... 8

2. All dorsal setae simple, seta al on palpfemur bifid...................................... T. macfarlanei Costa, 1962

- Some dorsal setae pilose, seta al on palpfemur spatulate....................................................... 3

3. Dorsal setae j1 feathered........................................................... T. fallax Holzmann, 1969

- Dorsal setae j1 simple.................................................................................. 4

4. Opisthonotum with 21 pairs of setae.................................................. T. biplumatus Karg, 1998

- Opisthonotum with 12–18 pairs of setae................................................................... 5

5. Opisthonotum much narrow than podonotum, with 12 pairs of setae................. T. hyalinus Yao, Jin & Zhang, 2019

- Opisthonotal width similar to width of podonotum, with 14-18 pairs of setae...................................... 6

6. Posterior margin of podonotum with convexity protruding into concavity in opisthonotal margin; opisthonotum with 14 pairs of setae................................................................ T. multisetus Yao, Jin & Zhang, 2019

- Posterior margin of podonotum straight or only sinuous; opisthonotum with 14–18 pairs of setae...................... 7

7. Length of idiosoma less than 500, opisthonotum with 14 pairs of setae, endogynium mushroom-shaped in outline, comprised of two circular parts as in T. ambulacralis ............ T. gracilis ( Karg, 1965) (= T. minor Holzmann, 1969 . Karg, 1971)

- Length of idiosoma exceeding 600, opisthonotum with 15–18 pairs of setae, endogynium ovate in outline, comprised of two circular parts, fused axially and forming the figure “8”............................. T. ambulacralis ( Willmann, 1949)

8. Epigynium regular (equilateral) triangle with straight lateral margins; gnathotectum central prong narrow, similar to lateral ones................................................................................................ 9

- Epigynium bell-shaped, with sinuous lateral margins, central prong of gnathotectum broader and more solid than the lateral prongs............................................................................................. 10

9. Sternal setae st2 simple and thin, distance between st2 greater than between st1; opisthogaster with seven pairs of setae, length of idiosoma 670–700.......................................................... T. medianus Tichomirov, 1977

- Sternal setae st2 stout, distance between st2 smaller than between st1; opisthogaster with eight pairs of setae, length of idiosoma ca. 560.......................................................................... T. triangulus Karg, 1978

10. Distance between sternal setae st2 evidently greater than between st3; opisthogastric setae JV4 simple, similar to other ventral setae; epigynium width greater than length.......................... T. pusillus ( Berlese, 1892) sensu Holzmann, 1969

- Distance between sternal setae st2 similar to that between st3; opisthogastric setae JV4 enlarged and terminally pilose; epigynium width not greater than length....................................................................... 11

11. Paragynal poroid iv3 circular rather than elongate................................ T. karuni Farahi & Witaliński, 1919

- Paragynal poroid iv3 elongate, similar in shape to poroids iv1 and iv2. .......................................... 12

12. Endogynium narrow, tubular, with separate elliptic anterior part, ca. 90 μm long, extending nearly along the entire length of the epigynium.................................................................... T. borealis Ma & Wang, 1996

- Endogynium cross-shaped, shorter than epigynium length.................................................... 13

13. Podonotum and opisthonotum fused, setae j1 and z1 on podonotal shield; sternal setae st2 somewhat thicker and shorter than st1; endogynium with open arms, ca. 58 long, its length not exceeding half of the length of the epigynium................................................................................................ T. gerdi Witaliński, 1917

- Podonotum and opisthonotum separate, setae j1 and z 1 in front of podonotal shield; sternal setae st2 clearly thicker and two times shorter than st1; endogynium with closed arms, ca. 95 long, posteriorly ending at st5 setae level....................................................................................... T. pseudogerdi Yao, Jin & Zhang, 2019