Agistemus rodriguezi Paktinat-Saeij & Cruz

Paktinat-Saeij, Saeid, Barroso, Geovanny & Cruz, Wilton Pires Da, 2017, Two new species of Stigmaeidae (Acari: Trombidiformes: Rhaphignathoidea) from Brazil, Zootaxa 4242 (2), pp. 372-382 : 373-375

Agistemus rodriguezi Paktinat-Saeij & Cruz sp. nov.

( Figs. 1–8 , 26–27 )

Diagnosis. Prodorsal and hysterosomal shields smooth; length of seta c1 longer than the distance between the base of c1 and d1; the ratio vi / vi–vi 2.4 (2.1–2.5); the ratio c1 / c1–c1 2.2 (2.1–2.8). Aggenital shield entire, bearing one pair of setae (ag1); seta g1 reaching base of ps3; femora I–IV 5-4 -2-2.

Description. Female (n = 7): Length of idiosoma 260 (227–303); width of idiosoma 200 (181–231); gnathosoma (including palp) 139 (126–136); subcapitulum 78 (66–79); palp 102 (92–101); chelicera 91 (90–97). Length of legs I–IV: 296 (277–290); 260 (237–261); 230 (220–233); 252 (240–255). Femur I 80 (75–82), genu I 24 (19–23), tibia I 54 (48–53), tarsus I 75 (70–78).

Dorsum of idiosoma ( Figs. 1 , 26 – 27 ). Idiosoma broadly oval in dorso-ventral view. Prodorsal shield triangular, indented posteriorly and smooth ( Figs. 1 ). Prodorsal shield with 3 pairs of setae (vi, ve and sci), one pair of eyes 10 (8–10) in diameter and one pair of postocular bodies (pob) 14 (13–15) in diameter; humeral shields smooth, bearing c2. Hysterosomal shield smooth, with five pairs of setae (c1, d1, d2, e1 and e2); intercalary shields smooth, with setae f1; suranal shield entire and smooth, with two pairs of setae, h1 and h2. Dorsal setae set on tubercles, long and barbed, with blunt tips, h1 and h2 are distinctly shorter. Lengths of dorsal setae: vi 53 (51–56); ve 74 (73–82); sci 63 (68–77); c1 66 (65–67); c2 48 (50–51); d1 70 (67–72); d2 68 (67–72); e1 75 (72–75); e2 73 (73–79); f1 53 (54–57); h1 34 (31–33); h2 23 (20–23). Distances between dorsal setae: vi– vi 22 (20–26); ve–ve 52 (50–59); vi–ve 23 (16–24); ve–sci 33 (31–38); sci–sci 100 (97–105); c1–c1 30 (23–29); c1–d1 58 (47–56); c1–c2 80 (75–83); c1–d2 60 (53–61); d1–d1 79 (67–79); d1–d2 27 (26–30); d1– e 1 55 (47–56); d1– e 2 32 (26–32); d2–d2 131 (121–129); d2– e 2 45 (38–45); e1– e 1 28 (21–26); e2–e2 103 (97–105); e1–f1 22 (24–32); f1–f1 52 (47–65); f1–h1 32 (28–45); h1–h1 13 (12–13); h1–h2 18 (16–20); h2–h2 46 (38–44). Ratios: pob / eye: 1.4 (1.4–1.6); vi / vi–vi 2.4 (2.1–2.5); c1 / c1–c1 2.2 (2.1–2.8); d1 / d1–d1 0.9 (0.8–1.0); e1 / e1– e 1 2.6 (2.7–3.0); f1 / f1–f1 1.0 (0.9–1.2); h1 / h1–h1 2.6 (2.3–2.6); c1–c1 / d1–d1 0.3 (0.3–0.4); c1–c1 / e1– e 1 1.0 (0.9–1.1); d1–d1 / e1– e 1 2.8 (2.7–3.0); h1 / h2 1.4 (1.3–1.6); c1–c1: d1–d1: e1–e1: f1–f1 = 1.0 (1.0–1.1): 2.8 (2.8–3.1): 1.0: 1.8 (1.7–2.1).

Venter of idiosoma ( Figs. 2, 3 ). Ventral surface ornamented with striations; bearing three pairs of setae (1a, 3a and 4a). Aggenital shield entire, horseshoe-shaped, bearing one pair of setae (ag1). Anogenital valves with one pair of genital (g1) setae and three pairs of pseudanal (ps1–3) setae. Seta g1 reaching base of ps3. Setae ps1 robust and slightly barbed ( Fig. 3 ). Measurements of setae: 1a 25 (22–26); 3a 25 (21–28); 4a 25 (20–26); ag1 12 (10–13); g1 13 (11–14); ps1 13 (12–15); ps2 16 (13–16); ps3 14 (13–14); g1–ps3 9 (8–9); g1–ps3 17 (15–17).

Gnathosoma. Subcapitulum ( Fig. 4 ) bearing subcapitular setae m 28 (28–31) and n 38 (38–44) and adoral setae or1 17 (16–17) and or2 17 (16–17). Distance m–m 39 (40–41), n–n 30 (32–35) and m–n 7 (7). Palpus ( Fig. 4 ), five segmented; palptrochanter without setae; palpfemur with two smooth and one barbed seta; palpgenu with one seta; 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. 2 , 5–8 ). Dorsalmost seta on femur I (dFI) barbed, 50 (48–50), 1.5 times length of h1; dorsalmost seta on genu I (dGI) barbed, 36 (36–40). Chaetotaxy: coxae (excluding 1a, 3a and 4a) 2(+1elcl)-1-2-2, trochanters 1-1-1-1, femora 5-4-2-2, genua 3(+1κ)-1-0-0, tibiae 5(+1φp)-5(+1φp)-5(+1φp)-5(+1φp), tarsi 12(+1ω)-9(+1ω)- 7(+1ω)-7. Length of solenidia: ωI 25 (24–25); ωII 23 (23–25); ωIII 15 (15–18).

Immature stages and male: Unknown.

Remarks. The new species resembles A. brideliae Gonzalez-Rodriguez, 1965 and A. striolatus Gonzalez- Rodriguez, 1965 in having dorsal shields without reticulations, one pair of aggenital setae (ag1) and the same femora, genua and tibiae chaetotaxy; however, it can be distinguished from A. brideliae by: 1) having most of dorsal setae at least 20% longer than those in A. brideliae ; 2) length of seta c1 longer than the distance between the base of c1 and d1 (c1> c1–d1) vs. shorter in the A. brideliae ; 3) seta d1 surpassing the base of e1 (d1> d1–e1) vs. shorter in the A. brideliae ; 4) length of seta d2 distinctly longer than the distance between the base of d2 and e2 (d2> d2–e2 or d2 / d2–e2: 1.5) vs. equal (d2 / d2–e2: 1.0) in the latter.

Agistemus rodriguezi sp. nov. differs from A. striolatus by: 1) the ratio c1 / c1–c1 2.2 (2.1–2.8) instead of 1.0 in the latter; 2) the ratio e1 / e1– e 1 2.6 (2.7–3.0) whereas approximately 1.3 in the latter; 3) setae ag1 on entire aggenital shield vs. setae ag1 being on separate small platelets in the A. striolatus .

Etymology. The species is named in honor of Prof. Roberto H. Gonzalez-Rodriguez (University of Chile, Maipu, Chile), for his great contribution to Acarology.

Type materials. Holotype female and six paratype females from leaves of Caiaué ( Elaeis oleifera (Kunth) Cortés , Arecaceae ) trees, 11 Dec. 2012 at experimental field Urubu river in Rio Preto da Eva, state of Amazonas, Brazil were collected by Wilton Pires da Cruz . Holotype and four paratype females are deposited in the Acarological collection of Departamento de Entomologia e Acarologia, ESALQ-USP, Piracicaba, São Paulo State, Brazil and two paratype females are deposited in the Acarological Collection , Department of Plant Protection , Faculty of Agriculture , University of Maragheh, Maragheh, Iran .

Figures

FIGURES 1 – 4. Agistemus rodriguezi Paktinat-Saeij & Cruz sp. nov. (Female). 1. Dorsal view of idiosoma, 2. Ventral view of idiosoma, 3. Ventral view of anogenital area, 4. Gnathosoma: subcapitulum (ventral), palp (dorsal).

FIGURES 5 – 8. Agistemus rodriguezi Paktinat-Saeij & Cruz sp. nov. (Female). 5. Leg I, 6. Leg II, 7. Leg III, 8. Leg IV.

FIGURES 26 – 27. Agistemus rodriguezi Paktinat-Saeij & Cruz sp. nov. (Female). Dorsal view of idiosoma.