Atractides (Tympanomegapus) omanensis, Smit & Pesic, 2010

Smit, H. & Pesic, V., 2010, New Species Of Water Mites From Oman, With Some Zoogeographical Notes (Acari: Hydrachnidia), Acarologia 50 (2), pp. 151-195 : 173-174

Atractides (Tympanomegapus) omanensis n. sp.

( Figures 16 A-E, 17, 18, 19A-D)

Type material — Holotype: male, unnamed stream crossing road to Al Fay , near Ray, Oman, 24°38.703 N 56°06.760 E, alt. 562 m, 15-xi-2008 . Paratypes: 0/1/0 (0/1/0 mounted), same data as holotype; 1/0/0 (1/0/0 mounted), stream Wadi Ghul , Oman, 23°10.297 N 57°11.996 E, alt. 805 m, 12-xi-2008 .

Diagnosis — Muscle attachments sclerotized, cheliceral claw relatively strong, P-3 ventral margins with one seta, little enlarged, sword seta on P-4 enlarged, not hair-like, on the level of distoventral hair, P-5 without cheeks; excretory pore sclerotized; leg claws with dorsal clawlet.

Description

General features — Dorsal integument: striated; muscle attachment plates: sexual dimorphism in the dorsal area. Genital field: Ac in triangular arrangement. Palp: weak sexual dimorphism, P-3 ventral margin with one seta, P-4 sword seta enlarged, inserted on level of the distoventral hair, P-5 without cheeks. I-Leg: setae S-1 and -2 inserted on the same level, distally truncate; leg claws with dorsal clawlet.

Male — (holotype, in parentheses measurement of specimen from stream Wadi Ghul). Idiosoma L/W (422)/(288). Dorsal shield ( Fig. 16A ) L/W 381 (372)/247 (247) including postoc and Dgl-3-6; ventral shield ( Fig. 16B ) L/W 394 (400)/344 (331), including coxae, Vgl-3 and -4, genital field, excretory pore and Vgl-1 and -2; coxal field: completely fused: Cx-III W 255. Palp ( Fig. 16C ): total L 189 (198), dL: P-1, 24 (25); P-2, 40 (45); P-3, 42 (42); P-4, 60 (63); P-5, 23 (23); %L: P-1, 12.7 (12.6); P-2, 21.2 (22.7); P-3, 22.2 (21.2); P-4, 31.8 (31.8); P-5, 12.2 (11.6); L P-2/P-4 0.67 (0.71); chelicera total L 142 (151), basal segment L 97 (108), claw L 49 (49), L ratio basal segment/claw 2.0 (2.2); capitulum ventral L 82 (83). Genital field: fused with the ventral shield, but suture lines still evident, W 89 (95), L Ac-1-3: 15 (13), 12 (12-14), 17 (15).

I-Leg ( Fig. 16 D-E): I-Leg-5 dL 79 (82), vL 62 (63), dL/vL 1.3 (1.3), HB 27 (28), dL/HB 2.9 (2.9), S-1 L 32 (36), L/W 10.3 (7.8), S-2 L 32 (36), L/W 10.3 (7.8), distance of sword setae at I-Leg-5 0 (0), L S-1/2 1.0 (1.0); I-Leg-6 L 80 (82), HB 19 (21), L/HB 4.3 (3.8); L I-Leg-5/6 0.98 (1.03).

Female — Idiosoma L/W 694/475; muscle attachment plates ( Fig. 17 ): Postoc and D-1 fused to a longish platelet, Dgl-3-6 separate, D-2-5 sclerotized, D-2 and -5 as roundish platelets, D-3 and - 4 as longish platelets, V-1-3 sclerotized. Coxal field ( Fig. 18 ): posterior margin of Cx-I truncated, apodemes of Cx-II forming an acute angle, coxae with borders of secondary sclerite; L 319, Cx-III W 380, Cx-I+II mL 134, Cx-I+II lL 233. Palp ( Figs. 19B ): palp total L 274, dL and %L (in parentheses): P-1, 32 (11.7); P-2, 62 (22.6); P-3, 63 (23.0); P-4, 82 (29.9); P-5, 35 (12.8); L P-2/P-4 0.76; chelicera ( Fig. 19D ) total L 292, basal segment L 195, claw L 108, L ratio basal segment/claw 1.8; capitulum ( Fig. 19A ) ventral L 129. Genital field ( Fig. 18 ): L/W 137/153, pregenital robust, halfmoon-shaped, L 117, genital plate L 75, L Ac-1-3: 24, 24, 27; egg maximum diameter (n=6) 113-118; excretory pore sclerotized; Vgl-1 fused to Vgl-2.

I-Leg ( Fig. 19C ): I-Leg-5 dL 111, vL 86, dL/vL 1.29, HB 34, dL/HB 3.3, S-1 L 42, L/W 9.1, S-2 L 42, L/W 9.1, distance of sword setae at I-Leg-5 0, L S- 1/2 1.0; I-Leg-6 L 106, HB 23, L/HB 4.6; L I-Leg-5/6 1.05.

Remarks — Due to the presence of dorsal shield and the ventral surface covered by an extended shield including coxae, Vgl-3 and -4, excretory pore and genital field in the male, and gnathosoma with elongated rostrum, the new species is similar to Atractides yukii Cook, 1967 ( India) . From the latter it can be distinguished in the following features: gnathosomal rostrum more slender and pointed, P- 3 ventral margins with one seta, sword seta on P-4 enlarged, not hair-like, setae S-1 and -2 inserted on the same level and presence of dorsal leg clawlets.

Etymology — The species is named for its occurrence in Oman.

Distribution — Oman.

Smit H. and Pe˘si´c V.

Figures

FIGURE 16: Atractides omanensis n. sp., male (A-D holotype, E paratype): (A) – dorsal shield; (B) – idiosoma, ventral view; (C) – palp, lateral view; (D-E) – I-Leg- 5 and - 6. Scale bars = 100 µm.

FIGURE 17: Atractides omanensis n. sp., female: idiosoma, dorsal view. Scale bar = 100 µm.

FIGURE 18: Atractides omanensis n. sp., female: idiosoma, ventral view. Scale bar = 100 µm.

FIGURE 19: Atractides omanensis n. sp., female: (A) – capitulum and palp, lateral view; (B) – palp, medial view; (C) – I-Leg- 5 and - 6; (D) – chelicera. Scale bars = 100 µm.