Atractides invidendus K. O. Viets, 1964

Pešić, Vladimir, Smit, Harry & Gerecke, Reinhard, 2011, New records of water mites of the genus Atractides Koch, 1837 (Acari: Hydrachnidia, Hygrobatidae) from South Africa, with descriptions of five new species, Zootaxa 2986, pp. 1-54 : 20-21

Atractides invidendus K. O. Viets, 1964

( Figs. 17–19 )

Material examined. South Africa: Mpumalanga province: DC 76 84 0/1/0; DC 81 84 0/2/0; DC 83 84 4/1 /3 (2/1/1 mounted); DC 84 84 0/3/0; DC 85 84 0/2/0. Western Cape province: DC 110 84 1/0/1. KwaZulu-Natal province: DC 92 84 0/1/0.

General features. Dorsal integument striated; muscle attachments unsclerotized. Coxal field: median suture Cx-I+II rather long, apodemes of Cx-II forming a 45° angle, width of borders of secondary sclerotization of Cx-III medially and Cx-IV medioposteriorly various from narrow to quite extended; medial margins of Cx-III+IV straight or broadly rounded, parallel to each other. Genital field: Ac in a curved line. Excretory pore smooth; Vgl-1 fused to Vgl-2. Palp: weak sexual dimorphism, ventral margin P-2-4 straight, P-4 elongated, sword seta between ventral hair insertions, but closer to distoventral hair. I-L-5 with subparallel dorsal and ventral margins, S-1 and -2 similar in shape with pointed distal tips, S-2 slightly bent inwards; I-L-6 curved, inflated proximally, from the centre to the claw furrow with parallel dorsal and ventral margins; leg claws with dorsal and ventral clawlets.

Morphology. Male (DC 83 84, n = 2): Idiosoma L/W 559–625/438–500; glandularia maximum diameter 32; coxal field L 430; Cx-I+II mL 147–153, lL 253–272. Genital field ( Fig. 17A ): due to the extended secondary sclerotization anterior margin convex and maximum width on the level of Ac-1, posterior margin indented, L/W 145– 151/154–161; L Ac 1–3: 37–39, 39–40, 32–39.

Palp ( Fig. 17C ): total L 316–320, dL: P-1, 28–29; P-2, 58–59; P-3, 66–67; P-4, 123–128; P-5, 39; L ratio P-2/ P-4, 0.48–0.52; P-4 elongated and thickened; capitulum vL 120; chelicera total L 180–198.

I-L ( Fig. 17D ): I-L-5 dL 151–158, vL 122–124, dL/vL ratio 1.24–1.27, HB 37–39, dL/HB 4.1, S-1 L 102–105, L/ W 16.9 –17.9, S-2 L 101–103, L/ W 13.4 –14.6, distance S-1-2, 7, L ratio S-1/2, 1.01; I-L-6 L 120–122, HB 19– 20, L/HB ratio 6.0–6.6; L ratio I-L-5/6, 1.24–1.32.

Female (DC 83 84): Idiosoma L/W 613/519; glandularia maximum diameter 34; coxal field L 422; Cx-III W 472; Cx-I+II mL 125, lL 258. Genital field ( Fig. 18 ): L/W 138/178, genital plate L 106–113, L Ac 1–3: 44, 38, 38.

Palp ( Fig. 19A ): total L 323, dL: P-1, 31; P-2, 66; P-3, 75; P-4, 109; P-5, 42; L ratio P-2/P-4, 0.61; P-4 slender than in males; capitulum vL 130; chelicera total L 222.

I-L ( Fig. 19B ): I-L-5 dL 178, vL 143, dL/vL ratio 1.25, HB 43, dL/HB 4.14, S-1 L 103, L/ W 14.7, S-2 L 106, L/ W 11.5, distance S-1-2, 9, L ratio S-1/2, 0.97; I-L-6 L 128, HB 22, L/HB ratio 5.8; L ratio I-L-5/6, 1.39.

Deutonymph (collected at DC 83 84 and suspected to represent this species): Idiosoma L/W 406/328; integument dorsally striated; muscle attachments unsclerotized; glandularia maximum diameter 22; coxal field L 250; Cx-III W 278; Cx-I+II mL 78, lL 153. Provisional genital field with two pairs of Ac, L/W 50/68; excretory pore smooth; Vgl-1 fused to Vgl-2.

Palp ( Fig. 19C ): total L 192, dL: P-1, 18; P-2, 39; P-3, 39; P-4, 65; P-5, 31; L ratio P-2/P-4, 0.6.

I-L ( Fig. 19D ): I-L-5 dL 111, vL 88, dL/vL ratio 1.26, HB 31.5, dL/HB 3.52, S-1 L 79, L/ W 18.8, S-2 L 80, L/ W 13.0, distance S-1-2, 6.0, L ratio S-1/2, 0.99; I-L-6 L 95, HB 17, L/HB ratio 5.6; L ratio I-L-5/6, 1.17.

Remarks. Due to the unsclerotized muscle attachments, similar palp morphology, an unsclerotized excretory pore, Vgl-1+2 fused, I-L-5 with S-1 and -2 similar in shape with pointed distal tips and S-2 slightly bent inwards, and especially in the characteristic medial margins of Cx-III+IV more or less parallel to each other, our specimens agree well with the description of Atractides invidendus .

Distribution. South Africa: Mpumalanga province: K.O. Viets (1964b), K.O.Viets (1968), present study; Western Cape province: present study; KwaZulu-Natal province: present study.

Figures

FIGURE 18. Atractides invidendus K. O. Viets, 1964, female, Blyde River: idiosoma, ventral view. Scale bar = 100 μm.

FIGURE 17 A – D. Atractides invidendus K. O. Viets, 1964, male, Blyde River: A = genital field; B = left Cx-IV; C = palp, medial view (P- 1 missing); D = I-L- 5 and - 6. Scale bars = 100 μm.

FIGURE 19 A – D. Atractides invidendus K. O. Viets, 1964 (A – B = female; C – D = deutonymph), Blyde River: A = palp, medial view; B, D = I-L- 5 and - 6; C = palp, lateral view. Scale bars = 100 μm.