Eustigmaeus Berlese, 1910

Paktinat-Saeij, Saeid, Bagheri, Mohammad, De Castro, Tatiane M. M. G. & De Moraes, Gilberto J., 2016, Two new species of Eustigmaeus Berlese (Acari: Trombidiformes: Stigmaeidae) from Brazil, with a key to the American species, Zootaxa 4066 (5), pp. 571-580 : 578-579

Key to females of Eustigmaeus Berlese, 1910 of America

1 Dorsal idiosomal setae acicular, clavate or flattened; smooth or sparsely barbed.................................... 2

- Dorsal idiosomal setae short, densely barbed or bushy....................................................... 30

2 With one pair of aggenital setae; dorsal body setae arcuate or flattened........................................... 3

- With two or three pairs of aggenital setae; dorsal idiosomal setae acicular or clavate............................... 10

3 Femur II with four setae; genua III with two setae........................................... E. smithi (Chaudhri)

- Femur II with five setae; genua III with one seta............................................................. 4

4 Coxisternal shield separated..................................................... E. modiola (Summers & Price)

- Coxisternal shield fused................................................................................ 5

5 Dimples on dorsal shields with vacuoles................................................................... 6

- At least most of the dimples on dorsal shields without vacuoles................................................. 7

6 Tarsus II with 8(+1ω) setae; dorsal setae slender, sharply pointed, with barbs......................... E. segnis (Koch)

- Tarsus II with 9(+1ω) setae; dorsal setae with broad membranous vanes...................... E. microsegnis (Chaudhri)

7 Dorsal idiosomal setae with barbs........................................................................ 8

- Dorsal idiosomal setae almost smooth..................................................................... 9

8 Tarsus II with 8(+1ω) setae; distance e1–e1 subequal to f1–f1................................. E. arcuata (Chaudhri)

- Tarsus II with 9(+1ω) setae; distance e1–e1 double f1–f1.................. E. floridensis Maake, Ueckermann & Childers

9 Tarsus II with 8(+1ω) setae; coxisternal shield smooth...................................... E. chilensis (Chaudhri)

- Tarsus II with 9(+1ω) setae; coxisternal shield reticulated...................................... E. oliveirai sp. nov.

10 With two pairs of aggenital setae........................................................................ 11

- With three pairs of aggenital setae....................................................................... 16

11 Setae 4a absent..................................................................... E. parviseta (Chaudhri)

- Setae 4a present..................................................................................... 12

12 Humeral callosities absent............................................................................. 13

- Humeral callosities present............................................................................ 14

13 Dorsal shields ornamented with minute dimples; sci short (10 Μm).......................... E. bryonemus Flechtmann

- Dorsal shields ornamented with polygonal dimples; sci normal (30–36 Μm)......................... E. arctica (Wood)

14 Tarsus IV with 6(+1ω) setae; trochanter III with one seta.......................... E. kauaiensis Swift, Gerson & Goff

- Tarsus IV with 7(+1ω) setae; trochanter III with two setae.................................................... 15

15 Aggenital area reticulated; dorsal setae clavate or acicular, with spinules and hyaline sheaths; length of setae ve distinctly greater than distance ve–sci.................................................... E. schusteri (Summers & Price)

- Aggenital area smooth; dorsal setae clavate or with acutely pointed apex, minute barbed and hyaline sheaths; length of setae ve not greater than distance ve–sci............................................................ E. rotunda (Wood)

16 Eyes absent......................................................................................... 17

- Eyes present........................................................................................ 19

17 Femur IV with three setae........................................................... E. parasitica (Chaudhri)

- Femur IV with two setae.............................................................................. 18

18 Dorsal idiosomal setae long, barbulate with blunt tips; coxisternal shields reticulate................ E. gorgasi (Chaudhri)

- Dorsal idiosomal setae relatively short, plumose; coxisternal shields smooth..................... E. gamma (Chaudhri)

19 Tarsus IV with 7 setae................................................................................ 20

- Tarsus IV with 7(+1ω) setae............................................................................ 24

20 Setae 4a absent...................................................................... E. capella (Chaudhri)

- Setae 4a present..................................................................................... 21

21 With two humeral callosities............................................................ E. lacuna (Summers)

- Without humeral callosity............................................................................. 22

22 Trochanter III with one seta; setae h1 and h2 simple, without hyaline sheaths; with extra shield on idiosoma.............................................................................................. E. piracicabensis sp. nov.

- Trochanter III with two setae; setae h1 and h2 clavate, with hyaline sheaths; not extra shield on idiosoma.............. 23

23 Dorsal shields strongly reticulate..................................................... E. reticulatellus (Habeeb)

- Dorsal shields uniformly dimpled, dimples circular to oval shape.................... E. clavata (Canestrini & Fanzago)

24 Humeral callosities absent............................................................... E. ovata (Chaudhri)

- Humeral callosities present............................................................................ 25

25 Dorsal idiosomal setae without hyaline sheaths; aggenital plate smooth or weakly reticulated........................ 26

- Dorsal idiosomal setae with hyaline sheaths; aggenital plate distinctly reticulated................................. 28

26 Ornamentation of dorsal shields faint, dimples shallow, no evident reticulum; approximate ratio of lengths ve: vi = 1.5, ve: c2 = 4.0; c2 very short 19 Μm.................................................................. E. ottavii (Berlese)

- Ornamentation of dorsal shields reticulate or polygonal; approximate ratio of lengths ve: vi = 1.0, ve: c2 = 1.3–1.6; c2 short 26– 31Μm.............................................................................................. 27

27 Dorsal shields uniformly ornamented with pits surrounded with polygonal walls; dorsal setae clavate and apically barbed; dis- tance d1–d1 about 1.5 times as long as distance e1–e1......................................... E. frigida (Habeeb)

- Dorsal shield with pores in marginal area, minute punctations and faint reticulations in central area; dorsal setae tapered with pointed tips, not barbed; distance d1–d1 about the same as distance e1–e1......................... E. najeeba (Habeeb)

28 With two pairs of subequal humeral callosities; dorsal shields distinctly reticulated................ E. acidophila (Wood)

- Anterior callosity distinctly larger than posterior callosity; dorsal shields faintly reticulate........................... 29

29 Dorsal shields ornamented with small, roughly oval, shallow dimples; dimples vacuolated mostly around the perimeters, with 0–3 central vacuoles; dorsal setae are thickest subapically and clavate, minutely barbed and with hyaline sheaths, h1 and h2 barbed, ve: c2 = 1.5; spine k on genu I approximately 1/3 as long as dorsal setae on genu I; humeral callosities punctuated finely................................................................................. E. gersoni (Wood)

- Dorsal shields minutely punctate, with dimples and vacuoles the bases of the dimples are unvacuolated; dorsal setae clavate to rod-like and with hyaline sheaths; ve: c2 = 2; spine k on genu I approximately 1/2 as long as dorsal setae on genu I, humeral callosities with pores.................................................................. E. rhodamela (Koch)

30 Femur II with four setae.............................................................. E. anauniensis (Ewing)

- Femur II with five setae............................................................................... 31

31 Eyes absent.................................................................... E. lirella (Summers & Price)

- Eyes present........................................................................................ 32

32 Coxisternal shields smooth; setae e1 about 17 Μm................................... E. craticola (Summers & Price)

- Coxisternal shields reticulated; setae e1 at least 32 Μm....................................................... 33

33 Dorsal idiosomal setae as long as or longer than the distances between their successive bases; longest spinules less than twice as long as diameter of setal axis......................................................... E. collegiensis (Wood)

- Dorsal idiosomal setae shorter than the distances between their successive bases; longest spinules more than twice as long as diameter of setal axis................................................................................. 34

34 Dimples on dorsal shields of uniform shape (polygonal) and size; c1–c1 approximately 68 Μm........ E. myrtae (Chaudhri)

- Dimples on dorsal shields varying in shape and size; c1–c1 approximately 54 Μm.................. E. plumifer (Halbert)