Atractides (s. str.) graecus K. Viets, 1950

Gerecke, Reinhard, 2021, The water mites of the family Hygrobatidae (Acari, Hydrachnidia) in Italy, Zootaxa 5009 (1), pp. 1-85 : 26

Atractides (s. str.) graecus K. Viets, 1950

(Figs 12; 31 M)

Material examined: Sardegna: I TG 17-03b, 0/2/0; Sicilia: All parts except for Sicani. I 39, 0/1/0 slide; I 45, 2/1/0 slide; I 46, 0/1/0 slide; I 168, 0/1/0 slide; I 177, 1/1/0 slide; I 184, 0/2/0 (0/1/0 slide); I 186, 1/0/0 slide; I 199, 0/1/2 slide; I 208, 3/0/0; I 239, 0/1/0; I 307, 0/1/0 slide; I 502, 2/0/0 slide; I 529, 1/0/0 slide; I 572, 0/1/0 slide; I 573, 0/1/0 slide; I 628, 0/1/0, slide; I 647, 0/4/0 (0/1/0 slide); I 657, 0/1/0, slide; I 662, 0/1/0 slide; I dp 12, 0/1/0 slide. 21 sites, 31 specimens .

Remark: As the variability of this species is little documented, measurement ranges and morphological details are given here for populations from the study area.

Males (n = 3): Idiosoma L/W 400-470/320-380. Venter: Fig. 12 F. Coxal field L/W 245-270/240-340; Cx-I+II mL 95-100, lL 170-185, W 215-230. I-L-5-6: Fig. 12 D. I-L-5 dL/vL 118-123/94-100, ratio 1.3-1.5, distal sector 36-40 %; HA 23-24, HB 28-30, HC 33-34, ratio dL/HB 4.1-4.3; S-1 L 36-39, L/W ratio 9,7-11,1; S-2 L 35-38, L/W ratio 7.8-8.8; distance S-1-2, 3, L ratio S-1/-2, 1.0; I-L-6 dL 100-105, HA 23-24, HB 23-24, HC 26-28; ratio dL/HB 4.1-4.4, dL/HC 3.8; dL ratio I-L-5/6, 1.17-1.18. Genital field (Fig. 12 G) L/W 70-90/85-100, anterior margin in juveniles equally rounded, in aged specimens more protruding, posterior margin with a shallow medial indentation; gonopore L 40-60, Ac in a curved line, surrounded by about 20 pairs of setae; maximum diameter Ac-1, 16-20; Ac-2, 16-20; Ac-3, 20-31. Gnathosoma L 65-80. Palp (Fig. 12 E) total L 256-268; L/H (ratio, rel. L [%]) P-1, 24- 25/20-21 (1.2, 9); P-2, 55-58/36-38 (1.5, 21); P-3, 64-65/31-33 (2.0, 24-25); P-4, 86-93/29-30 (3.9-3.1, 34-35); P-5, 26-28/10 (2.6-2.8, 10); L ratio P-2/P-3, 0.85-0.88; P-2/P-4, 0.62-0.64; P-3/P-4, 0.70-0.75.

Females (n = 3): Idiosoma L/W 520-650/390-450, coxal field L/W 280-300/325-345; Cx-I+II mL 105-110, lL 195-210, W 240-265. I-L-5-6: Fig. 12 C. I-L-5 dL/vL 135-148/110-120, ratio 1.2, distal sector 25-30 %; HA 26- 29, HB 31-33, HC 36-38, ratio dL/HB 4.1-4.5; S-1 L 40-45, L/W ratio 10.6-12.0; S-2 L 38-41, L/W ratio 7.5-8.3; distance S-1-2, 4, L ratio S-1/-2, 1.1-1.2; I-L-6 dL 110-115, HA 23-25, HB 24-26, HC 28; ratio dL/HB 4.2-4.8, dL/HC 4.0-4.2; dL ratio I-L-5/6, 1.23-1.28. Genital field (Fig. 12 A) L 120-160, pregenital sclerite crescent-shaped, with fine tips, postgenital sclerite irregularly bowed, with concave anterior margin, genital plates L/W 75-85/25-30, weakly curved, anteriorly forming a blunt tip, posteriorly rounded, bearing 10-12 pairs of fine, hair-like setae; in general, posterior Ac larger than the others, maximum diameter Ac-1, 19-20; Ac-2, 18-21; Ac-3, 21-28. Gnathosoma L 85-100. Palp (Fig. 12 B) total L 303-316; L/H (ratio, rel. L [%]) P-1, 28-29/24-25 (1.1-1.2, 9); P-2, 65-68/45-48 (1.4-1.5, 21-22); P-3, 83-85/38-40 (2.1-2.3, 27); P-4, 98-106/25-28 (3.6-4.1, 32-34); P-5, 28-30/10-14 (2.2-2.8, 9- 10); L ratio P-2/P-3, 0.79-0.82; P-2/P-4, 0.64-0.69; P-3/P-4, 0.80-0.85. P-2 and P-3 with straight ventral margins, P-4 slenderer than in males, fine dorsal setae less numerous.

Habitat: Rhithrobiont, crenophilous. In Sicily mostly at middle altitude, 185-1150 m, 14 records from lower order streams, four from shaded, weakly seeping springs; in many cases only single specimens .

Distribution: Mediterranean. First records from Italy.