Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh and Ueckermann

Eghbalian, Amir Hossein, Khanjani, Mohammad, Safaralizadeh, Mohammad Hassan & Ueckermann, Edward A., 2016, New species of Hexabdella and Neomolgus (Acari: Prostigmata: Bdellidae) from Iran, Zootaxa 4072 (2), pp. 291-300 : 292-295

Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh and Ueckermann sp. nov.

( Figs. 1–10 )

Diagnosis. Two pairs of eyes present, fixed cheliceral digit as long as movable digit, chelicerae striated, coxa II with three setae, basifemora II and IV with eight and four setae respectively, genu IV with 5 (+1 s) setae, solenidotaxy of tibiae I–IV 3–2 –1–0.

Female (n= 4). Total body length (including gnathosoma from apex of hypostome to posterior margin of idiosoma) 602 (608–628), body length (excluding gnathosoma) 446 (455–470); width 270 (230–273).

Dorsum ( Fig. 1 ). Prodorsum between setae vi and sci with irregularly broken longitudinal striae; prodorsum with two pairs of eyes, diameters of anterior lateral eye 8 (7–8) and posterior lateral eye 5 (4–5). Striae anterior to internal verticals (vi) broken and transverse; all dorsal setae finely serrate; hysterosomal setae not extending to bases of setae next behind (except seta h1). Dorsum of hysterosoma with fine, continuous and transverse striae between setae (c1, d1, e1, f1, h1 and h2), but striae obliquely longitudinal between setae c1–2; seta sce the longest and h2 and f2 the shortest; hysterosomal region with three cupules (ia, im and ip) at level of setae d, e and f1 ( Fig. 1 ). Measurements of dorsal setae as follows: vi 98 (88–93), ve 41 (38–39), sce 69 (65–68), sci 130, c1 47 (50–51), c2 50 (40–45), d1 36 (34–38), e1 35 (33–38), f1 41 (35–36), f2 30 (28–30), h1 47 (43–45), h2 30 (27–30). Distance between dorsal setae: vi– vi 78 (73–75); ve–ve 113 (110–113); vi–ve 33 (30–33); ve–sce 40 (38–40); sci–sci 93 (83– 87); sce–sci 9 (8–10); sci–c1 72 (68–69); sci–c2 102 (103–105); c1–c1 77 (77–78); c1–c2 75 (67–70); c1–d1 60 (58–64); d1–d1 64 (65–68); d1– e1 55 (48–51); e1– e1 80 (70–83); e1–f1 55 (50–54); f1–f1 48 (43–49); f1–f2 33 (33–38); h1–h 24 (27–28); h1–h2 28 (20–27); h2–h2 80 (70–76). Ratio: vi / ve 2.30 (2.40); vi / sce 0.75 (0.68–0.72); sci / sci–sci 1.39 (1.57–1.48); vi/vi–vi 0.1.30 (1.30–1.70), c1 / c1–c1 0.61 (0.64–0.65), d1 / d1–d1 0.6 (0.50–0.58), e1 / e1– e1 0.44 (0.4–0.54), f1 / f1–f1 0.85 (0.73–0.81), h1 / h1–h1 1.96 (1.59–1.61), h2/h2–h2 0.34 (0.4–0.43), h1/h2 1.74 (1.43–1.50), c1–c1: d1–d1: e1–e1: f1–f1: 1.60 (1.60–1.80): 1.33 (1.39–1.51): 1.67 (1.63–1.69): 1.00 (1.00).

Gnathosoma ( Fig. 4 ). Subcapitulum 155 (148–165) long, width at base 75 (66–78); base of gnathosoma with transverse striae; palp: five–segmented, tibiotarsus with three setae + one solenidion + two long end setae, DES and VES 83 (83) and 108 (106–108) respectively; genu with four setae; telofemur with one seta; basifemur with five setae; trochanter without setae; measurements of palp segments as follows: trochanter 11 (10–12), basifemur 58 (50–53), telofemur 22 (22–23), genu 12 (13–15), tibiotarsus 35 (35–38). Subcapitulum with six pairs of long ventral subcapitular setae (vh1–6), distal pair (vh6) 36 (33–34) about 1.5x length of proximal pair (vh1) 21 (19–21); two pairs of short adoral setae near tip of hypostome, avs 10 (11) and ad 9 (8–10). Chelicerae 143 (138–141) long, width 42 (36–38), finely striated and with two dorsal setae (ch1–2), proximal seta 35 (33–35), and distal seta 50 (46–48), respectively, movable chela with one small tooth and fixed chela smooth and attenuate, equal in length to movable chela; distal seta (ch1) short, not extending to base of chela ( Fig. 4 ).

Venter ( Fig. 5 ). Striae between coxae I–II and III– IV longitudinal and between coxae II–III finely broken and oblique. One pair of setae between coxae IV. Aggenital region with nine pairs of setae (ag1–9) by genital valves each with nine pairs of setae (g1–9) ( Fig. 5 ); anal region surrounded with oblique continuous striae and three pairs of smooth setae (ps1–3): ps1 33 (33–38), ps2 23 (23–25) and ps3 16 (16–18) long ( Fig. 5 ).

Ovipositor ( Fig. 6 ). Ovipositor as indicated in Figure 6 ; tube like, with 18 smooth setae.

Legs ( Figs. 7–10 ). Measurements of legs I-IV: I 255 (238–243), II 231 (215–218), III 272 (250–253), IV 343 (315–338). Setal formulae of leg segments (solenidia in parentheses): coxae I–IV: 5–3–5 (right leg of holotype with 6)–2; trochanters I–IV: 1–1–2–1; basifemora I–IV: 8–8–7–4; telofemora I–IV: 5–5–5–5; genua I–IV: 4ts,1 s –4ts,1 s – 4ts,1 s –5ts,1 s; tibiae I–IV: 6ts,3 f,1tr–7ts,1 f,1bls–7ts,1 f –6ts,1tr; tarsi I–IV: 18ts,4 w, 1 e –16ts,2 w,1 e –17ts,1tr–15ts,1 w ( Figs. 7–10 ).

Male and immatures: Unknown.

Habitat. Litter under oak trees.

Distribution. Only known from Western Iran.

Remarks. Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh and Ueckermann sp. nov. is closely related to H. mexicana ( Baker & Balock, 1944) , redescribed by Atyeo (1960), by having: tibiae I, IV and tarsus III, each with one trichobothrium; opisthosomal setae not branched distally; two pairs of eyes; palp basifemur with five setae; solenidotaxy of tibiae I–IV 3–2 –1–0; it however differs in having: 1) striae between setae vi and sci irregularly broken and longitudinal in the former instead of finely and regularly broken in the latter; 2) fixed digit of equal length as movable digit, instead of two thirds the length of movable digit; 3) genital valve with nine pairs of setae in H. quercusi sp. nov. opposed to eight pairs of setae in H. mexicana ; 4) coxa II with three setae in new species while four setae in H. mexicana ; 5) subcapitular setae smooth instead of finely serrate; 6) basifemora II and IV with eight and four setae respectively versus seven and five; 7) telofemur IV with five setae instead of four setae; 8) genu IV with 5 (+1σ) setae in H. quercusi whereas 4 (+1σ) in the H. mexicana ; 9) tibiae II–IV: 7ts–7ts–6ts vs. 5ts–5ts–5ts; 10) tarsi I–IV 18 ts–16ts–17ts–15ts opposed to tarsi I–IV: 14ts–10ts–9ts–8ts.

The new species also resembles H. persiaensis Paktinat Saeej, Bagheri, Saboori & Ueckermann, 2014 , in having mostly the same leg chaetotaxy, smooth dorsal idiosomal setae and fixed digit of equal length as the movable digit; however it differs by: 1) palpal basifemur with five setae in the former while six setae in the latter; 2) basifemur III with seven setae in the new species whereas six setae in H. persiaensis ; 3) genital valve with nine pairs of setae in H. quercusi sp. nov. while eight pairs of setae in H. persiaensis ; 4) aggenital region with nine pairs of setae instead of eight; 5) marginal region between dorsal setae d1 and e1 with continuous striae in the former but fine broken striae in the latter; 6) marginal regions between legs II and III with broken striae in new species whereas continuous striae in H. persiaensis ; 7) aggenital setae ag 1–5 covered in continuous striae in new species but all aggenital seta, ornamented, on broken striae in H. persiaensis ; 8) tarsi I, II and IV with 18, 17 and 15 setae vs 19(20), 16 and 16 setae.

Etymology. The specific epithet is derived from Quercus , due to the oak-dominated forest where the new species was collected.

Type material. The holotype and three paratype females were collected from soil and litter under oak trees, Quercus brantii Lindl , ( Fagaceae ), Baneh, Kurdistan Province, Iran, (35° 59' N, 46° 53' E, a.s.l. 1540 m), 17 January 2013, Col. Amir Hossein Eghbalian. Holotype and two paratype females ( EHBH 15010 and EPBH 15011– 12, respectively) are deposited in the Mites Collection of the Acarology Laboratory, University of Bu–Ali Sina, Hamedan, Iran, and one paratype female (slide specimen) will be deposited in the Mites Collection of Arachnida, Plant Protection Research Institute, Pretoria, South Africa.

Figures

FIGURES 1 – 6: Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh and Ueckermann sp. nov. (Female): 1. Dorsum of idiosoma; 2. Prodorsal seta vi; 3. Prodorsal seta sce; 4. Gnathosoma; 5. Venter of idiosoma; 6. Ovipositor.

FIGURES 7 – 10. Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh and Ueckermann sp. nov. (Female): 7. Leg I; 8. Leg II; 9. Leg III; 10. Leg IV.