Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri

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 : 572-574

Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov.

( Figs. 1–10 , 19, 21–22 )

Female (n = 3): Length of idiosoma 292 (321–330); gnathosoma 102 (103–110); width of idiosoma 231 (253–268). Length of legs I–IV: 237 (241–245); 195 (196–197); 187 (183–192); 225 (225–238).

Dorsum of idiosoma ( Figs. 1 , 19 ). Covered by two shields, leaving exposed margin of unsclerotized cuticle around edges; shields ornamented with polygonal depressions, without vacuoles but with fine punctations ( Figs. 2 , 19 ); without callosities between idiosomal shield and humeral shield. Prodorsal shield triangular and bearing four pairs of setae (vi, ve, sci and sce) and one pair of eyes between setae ve and sci. Humeral shields subtriangular, ornamented with depressions and bearing c2; hysterosomal shield with six pairs of setae (c1, d1, d2, e1, e2 and f1); dorsal body setae ( Figs. 3 , 22 ) inserted on protuberances, subequal, smooth and clavate with hyaline sheaths, except h1 and h2 setiform and distinctly shorter. Lengths of dorsal setae: vi 63 (53–58); ve 70 (70–73); sci 60 (53– 58); sce 62 (58–63); c1 62 (54–58); c2 33 (30–34); d1 67 (65–66); d2 69 (60–64); e1 72 (68–70); e2 62 (53–62); f1 54 (47–52); h1 22 (20–22); h2 15 (11–14). Distances between dorsal setae: vi– vi 18 (17–18); ve–ve 65 (65–67); vi– ve 50 (53–55); ve–sci 30 (26–28); sci–sci 110 (106–109); sce–sce 145 (142–150); sci–sce 26 (22–25); c1–c1 78 (72–75); c1–d1 50 (51–55); c1–c2 76 (85–96); c1–d2 33 (30–36); c2–c2 218 (244–247); d1–d1 74 (72–77); d1–d2 48 (52–53); d1– e1 58 (63–65); d1– e2 34 (32–33); d2–d2 140 (136–141); d2– e2 60 (62–63); e1– e1 68 (65–70); e1– e2 40 (40–47); e2–e2 115 (114–118); e1–f1 43 (45–50); f1–f1 67 (58–60); h1–h1 33 (40–42); h2–h2 42 (47–50); h1–h2 8 (8).

Venter of idiosoma ( Fig. 4 ). Endopodal plates separated medially, reticulate and punctate, bearing three pairs of setae (1a, 3a and 4a). Anogenital area reticulate, but anal valves smooth; with three pairs of aggenital (ag1–3) and three pairs of pseudanal (ps1–3) setae. Suranal shield situated ventrally, pressed against anogenital shield, with depressions and punctate, bearing h1 and h2, adjacent to posterior horseshoe-shaped shield ornamented by tiny depressions ( Fig. 5 ). Measurements of setae: 1a 20 (17–18); 3a 22 (19–20); 4a 23 (20–21); ag1 11 (11–12); ag2 17 (14–17); ag3 12 (13–14); ps1 12 (11–12); ps2 11 (9–10); ps3 9 (7–9).

Gnathosoma. Subcapitulum ( Fig. 6 ) reticulate with fine punctations, bearing subcapitular setae m 16 (15–16) and n 17 (15–16) and adoral setae or1 10 (11) and or2 12 (11–12). Distance m–m 20 (18–19) and n–n 28 (28–30). Palpus 62 (64–68) long ( Fig. 6 ), five segmented; palptrochanter without setae; palpfemur with three setae; palpgenu with two setae; palptibia with two tactile setae + one well-developed claw + one spine-like accessory claw; palptarsus with four tactile setae + one solenidion (ω), one subapical eupathidium and one distal trifid eupathidium.

Legs ( Figs. 7–10 ). Setation: coxae (excluding 1a, 3a and 4a) 2-2-2-2, trochanters 1-1-1-1, femora 6-5-3-2, genua 3(+1κ)-3(+1κ)-1-1, tibiae 5(+1φ+1φρ)-5(+1φ)-5(+1φ)-5(+1φ),tarsi 13(+1ω)-9(+1ω)-7(+1ω)-7. Length of solenidia: ωI 19 (18–19); ωII 22 (20–23); ωIII 8 (8–9); φI 9 (11–12); φρI 24 (19–22); φII 18 (18–20); φIII 17 (16– 19). φIV 23 (21–22).

Immature stages and male: Unknown.

Remarks. The new species is distinguished from all other Eustigmaeus species by having the extra horseshoeshaped shield adjacent to the suranal shield. It resembles Eustigmaeus collarti ( Cooreman, 1955) and E. distinctus ( Wood, 1966) in having dorsal ornamentations, endopodal shields separated, and the same femora and genua chaetotaxy; however, it can be distinguished by 1) lacking the solenidion on tarsus IV (7+1ω in other species), 2) one seta on trochanter III (two in other species), 3) three pairs of aggenital setae (two pairs in other species), 4) endopodal shield reticulate (smooth in other species). Furthermore, the new species differs in the shape of dorsal setae from E. collarti .

Also, E. piracicabensis sp. nov. resembles E. reticulatellus (Habbeb, 1961) in having three pairs of aggenital setae, separate and reticulate endopodal shields, and the chaetotaxy of the femora, genua and tarsi; but it differs from the latter by having one seta on trochanter III instead of two, anogenital area reticulate instead of smooth, and setae h 1 and h 2 simple instead of clavate with hyaline tips.

Etymology. The epithet piracicabensis refers to “from Piracicaba”, the type locality of the new species.

Type material. Holotype female and two paratype females from soil and humus under rubber trees ( Hevea brasiliensis Müell. Arg. ), collected on March 28, 1999 at Piracicaba, state of São Paulo, Brazil by J.L. Mineiro. All types deposited at the mite reference collection of Departamento de Entomologia e Acarologia, ESALQ-USP, Piracicaba, São Paulo State, Brazil.

Figures

FIGURES 1 – 6. Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov. (Female): 1. Dorsal view of idiosoma, 2. Dorsal dimples, 3. Dorsal setae, 4, 5. Ventral view of idiosoma, 6. Gnathosoma: Subcapitulum (Ventral view), Palp (Dorsal view).

FIGURES 7 – 10. Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov. (Female): 7. Leg I, 8. Leg II, 9. Leg III, 10. Leg IV.

FIGURES 19 – 22. 19. Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov. (Female): Dorsal view of idiosoma, 20. Eustigmaeus oliveirai Paktinat-Saeij & Bagheri sp. nov. (Female): Dorsal view of idiosoma, 21. Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov. (Female): Ventral view of idiosoma (horseshoe shield), 22. Eustigmaeus piracicabensis Paktinat-Saeij & Bagheri sp. nov. (Female): Dorsal setae.