Gymnostigmaeus akaminei, Ehara & Ueckermann, 2006

Ehara, Shôzô & Ueckermann, E. A., 2006, A new genus of Stigmaeidae (Acari: Prostigmata) from Okinawa Island, Zootaxa 1160, pp. 29-36 : 31-35

Gymnostigmaeus akaminei n. sp. ( Figs. 1–15 )

(Japanese name: Shiba­suji­nagahishidani)

Description

FEMALE (measurements: n=10)

Dimension of body: length of body, including rostrum, 390 (436); excluding rostrum, 340 (385); width of body 150 (188).

Rostrum reaching approximately middle of tibia I ( Fig. 1 ). Subcapitulum with longitudinal, often dotted striae ( Fig. 7 ); lengths of subcapitular setae (mean±SE): m 10.2±0.3 (9.1), n 11.6 ±0.3 (11.5); distances: m ­m 20.7±0.4 (20.5), n ­ n 24.7±0.8 (27.3). Length of cheliceral stylet: 24.3±0.2 (25.3).

Chaetotaxy of palpus (from trochanter to tarsus): 0­3­1­3+ claw­4+ 2 terminal eupathidia +1 solenidion ( Fig. 8 ).

Idiosoma elongate­oval (anterior part of opisthosoma often dilated); dorsum without shields and platelets, entirely striated ( Fig. 1 ). Dorsal idiosomal setae faintly barbed. Prodorsum with longitudinal striae except for transverse striae anteriorly, in front of setae v2, and posteriorly, beyond setae sc2. One pair of eyes; postocular bodies absent. Opisthosomal dorsum mainly with longitudinal striae except between setae f1; region anterior to suranal area and behind setae h1 with transverse striae. Lengths of dorsal setae: v2 6.9±0.3 (­), sc1 10.1±0.2 (10.1), sc2 18.8±0.2 (18.4), c1 13.7±0.3 (13.4), c2 21.1±0.6 (20.5), d1 13.4±0.3 (13.2), d2 14.1±0.1 (13.8), e1 13.2 ±0.2 (13.4), e2 11.3 ±0.3 (11.5), f1 16.3±0.4 (16.6), h1 20.1±0.5 (19.8), h2 28.7±1.1 (28.8); distances: v2­v2 16.1±0.6 (19.4), v2 ­sc1 24.8±0.5 (22.9), sc1­sc2 34.8±0.9 (39.5), c1­c1 40.3±1.7 (49.0), c1­d1 56.6±1.2 (58.7), d1­d1 45.6±2.1 (57.7), d1­d2 37.4±1.5 (44.8), d1­ e1 43.6±0.6 (44.6), e1­ e1 28.2±1.1 (36.3), e1­ e2 32.7±1.1 (38.3), e1­f1 26.9±0.8 (30.4), f1­f1 45.6±0.6 (50.2).

Venter partly with transverse striae but, longitudinal between setae 3a and ag1 ( Fig. 2 ). Coxisternal shields absent. Lengths of intercoxal setae: 1a 17.3±0.3 (17.4), 3a 18.2±0.5 (20.1), 4a 11.3±0.3 (11.1); distances: 1a ­1a 18.2±0.7 (22.9), 3a ­3a 64.7±2.2 (76.6), 4a ­4a 16.6±1.0 (24.1). Anogenital area with 3 pairs of aggenital setae, 1 pair of genital setae and 3 pairs of pseudanal setae ( Figs. 1, 2 ); lengths: ag1 12.2±0.3 (12.6), ag2 13.7±0.9 (11.9), ag3 21.6±0.5 (22.3), g1 11.3±0.2 (11.5), ps1 21.9±0.3 (21.3), ps2 15.9±0.9 (13.6), ps3 14.4±0.3 (15.6).

Leg tarsi with membranous arolium surrounding bases of claws ( Figs. 3–6 ). Lengths of legs I–IV (base of coxae to tip of claw): leg I 144 (148), leg II 117 (117), leg III 121 (122), leg IV 127 (130). Chaetotaxy of leg segments (solenidia in parentheses) ( Figs. 5–8 ): coxae 2+1 elcp ­1­2­2, trochanters 1­1­1­1, femora 5­4­2­2, genua 4­1­0­0, tibiae 5 (1)­5 (1)­5­5, tarsi 13 (1)­8 (1)­7 (1)­7; lengths of solenidia: I 7.8±0.1 (7.5), II 6.3±0.1 (6.2), III 3.3±0.1 (3.2).

MALE (measurements: n=2 or n=4)

Dimension of body: length of body, including rostrum, 298; excluding rostrum, 257; width of body 122.

Lengths of subcapitular setae: m 9.5, n 9.5; distances: m­m 21.1, n­n 22.1; length of cheliceral stylet: 23.4. Palpus similar to female.

Idiosoma slender, tapering caudally. Dorsum devoid of shields and platelets, striae mostly longitudinal and transverse; prodorsum with a vortically striate area medially ( Fig. 9 ). Lengths of dorsal setae: v2 6.0, sc1 7.5, sc2 15.9, c1 9.9, c2 17.3, d1 10.1, d2 10.9, e1 5.7, e2 6.0, f1 8.9, h1 10.6, h2 26.2; distances: v2­v2 17.8, v2 ­sc1 20.9, sc1­sc2 30.3, c1­c1 34.8, c1­d1 36.7, d1­d1 30.2, d1­d2 30.2, d1­ e1 27.4, e1­ e1 26.1, e1­ e2 21.1, e1­f1 19.3, f1­f1 36.3.

Venter striate as in Fig. 10 . Lengths of intercoxal setae: 1a 13.7, 3a 13.4, 4a 8.3; distances: 1a­1a 18.8, 3a­3a 50.2, 4a­4a 13.0. Lengths of anogenital setae: ag1 9.2, ag2 12.4, ag3 17.9, ps1 10.1, ps2 6.3, ps3 5.8. Aedeagus as illustrated in Fig. 11 .

Lengths of legs: leg I 123, leg II 106, leg III 110, leg IV 115. Chaetotaxy of leg segments (solenidia in parentheses) ( Figs. 12–15 ): coxae 2+1 elcp ­1­2­2, trochanters 1­1­ 1­1, femora 5­4­2­2, genua 4­1­0­0, tibiae 5 (1)­5 (1)­5­5, tarsi 13 (2)­8 (2)­7 (1)­7; lengths of solenidia I 1 6.8, I 2 7.6, II 1 5.7, II 2 5.9, III 2.8.

Type series

Holotype female (NSMT­Ac 12063): Onna­son, Okinawa Island, Japan, 28­III­2004 (H. Akamine leg.), on Zoysia tenuifolia Willd. ( Poaceae) . Paratypes: 5 females (NSMT­Ac 12064­12066) & 1 male (NSMT­Ac 12067), data same as for holotype ; 4 females and 1 male (ARC­Pl. Prot. Res. Inst., Pretoria ), data same as for holotype.

FIGURES 12–15. Gymnostigmaeus akaminei n. gen., n. sp. (male). 12, leg I; 13, leg II; 14, leg III 15, leg IV.

;

Etymology The new species is named in honor of Dr. H. Akamine (Faculty of Agriculture, University of the Ryukyus) who collected the present material.

Biology

Specimens of this species were collected together with the false spider mite Dolichotetranychus zoysiae Ehara (Tenuipalpidae) on the lawngrass Zoysia tenuifolia on Okinawa Island. Judging from the general habits of stigmaeids associated with phytophagous mites (e.g., Santos & Laing, 1985), G. akaminei n. sp. is presumed to be an effective predator of the eggs of D. zoysiae attacking Zoysia spp.

Figures

FIGURES 1–2. Gymnostigmaeus akaminei n. gen., n. sp. (holotype female). 1, dorsum; 2, venter.

FIGUIRES 3–6. Gymnostigmaeus akaminei n. gen., n. sp. (female). 3, leg I; 4, leg II; 5, leg III; 6, leg IV.

FIGURES 7–11. Gymnostigmaeus akaminei n. gen., n. sp. 7, subcapitulum of female; 8, tarsus and tibia of female palpus; 9, dorsum of male; 10, venter of male; 11, aedeagus.

FIGURES 12–15. Gymnostigmaeus akaminei n. gen., n. sp. (male). 12, leg I; 13, leg II; 14, leg III 15, leg IV.

FIGURES 12–15. Gymnostigmaeus akaminei n. gen., n. sp. (male). 12, leg I; 13, leg II; 14, leg III;