Unionicola hankoi Szalay, 1927

(Figs 16A–D, 17A–E)

Material examined. 17 males, 8 females: Russia, Samara Province, Stavropol District, small lake near village Kol’tsovo, July 1992, leg. P.V. Tuzovskij. Additional material: 2 males: Ukraine, Zhitomir Province, Sluch River near Baranovka City, 29.07.2011, leg. L.N. Yanovich, T.V. Shevchuk. All males and females are collected freeswimming.

Diagnosis. Adults. Dorsum with two pairs of unequal platelets; coxal plates III+IV as long as wide with straight medial margin; P-3 with long lateroproximal and short distal setae, P-4 tapering distally, with two unequal ventrolateral and one ventrodistal tubercles, P-5 very short, with two long, thick and pointed distal spine-like setae (dorsal and ventral); anterior genital plates of female wide without anterior subcutaneous projections, with two short, thick subequal spine-like posteromedial setae, posterior genital plates with 1 short, thin anteromedial seta; genital plates of male wide, fused to each other by anterior and posterior ends, gonopore narrow, acetabula in both sexes small and occupy less than one half of each plate; claws of legs I thick, hook-like, claws of legs II–IV thin, sickle-shaped.

Description. Both sexes. Dorsum with two pairs of platelets, anterior platelets elongate and much larger than posterior ones (Fig. 16A). Anterior and posterior coxal groups (Fig. 16B) divided by narrow interspace; sclerites, bearing setae and glandularia Le, considerably larger than sclerites bearing other idiosomal setae. Apodemes of first coxal group rather long and extending posteriorly to anterior edge of third coxae. Coxal plates III+IV as long as wide (L/W ratio 1.00–1.15) with straight medial margin. Surface of all coxal plates with reticulations.

Pedipalps (Fig. 17A) short and stocky, P-2 with four setae, P-3 with lateroproximal and distal setae, lateroproximal seta longer than dorsal; P-4 tapering distally, with two unequal ventrolateral tubercles proximally to middle of segment each bearing thin, short seta and one ventrodistal tubercle bearing short peg-like seta and one dorsoproximal long, thin seta; P-5 very short, with two long and pointed distal spine-like setae (dorsal and ventral), two short ventral peg-like setae with rounded tips, and five thin unequal setae.

Figure 17B shows the proportion and chaetotaxy of I-Leg-4–6; I-Leg-5 slightly thickened distally and bearing distal denticulate seta. Legs II–IV long, slender; all segments, except trochanter, cylindrical and with swimming setae. The number of distal swimming setae on legs IV is as follows (Fig. 17C): one on telofemur, three on genu and tibia. Swimming setae on leg II shorter than swimming setae on legs III–IV; swimming setae on IV-Leg-5 much shorter than IV-Leg-6. Claws of legs I (Fig. 17D) thick, hook-like with two nearly subequal clawlets; claws of legs II–IV sickle-shaped with short dorsal clawlet and long ventral one (Fig. 17E).

Female. Anterior genital plates wide without anterior subcutaneous accretion each, with two short (rarely three) thick subequal spine-like posteromedial setae and two short, thin long setae each; posterior plates more or less triangular, each with 1 short, thin anteromedial seta and 3–4 thin setae (Fig. 16C).

Measurements (n=8). Idiosoma L 570–815, anterior dorsal platelets L 54–60, W 18–21; coxae III+IV L 185–200, W 175–185; anterior genital plates L 42–48, W 72–78; posterior genital plates L 90–100, W 65–75; pedipalpal segments (P-1–5) L: 17–30, 120–130, 38–43, 105–115, 16–25; leg segments L: I-Leg- 1–6—55 –65, 105–115, 105–115, 120–140, 120–140, 95–105; II-Leg- 1–6—55 –65, 95–105, 145–165,175–190,160–180; III-Leg- 1–6—55 –65, 105–125, 105–115, 145–165, 180–205, 160–180; IV-Leg- 1–6—90 –105, 120–140, 130–140, 175–195, 205–220, 180–190.

Male. Genital plates (Fig. 16D) wide fused to each other by anterior and posterior ends, usually with 5 acetabula (rarely 4 or 6) and 7–10 thin setae on each side; gonopore narrow.

Measurements (n=10). Idiosoma L 570–655; coxae III+IV L 185–200, W 175–185; genital field L 140–155, W 130–140; pedipalpal segments (P–1–5) L: 15–25, 105–140, 30–40, 95–105, 12–17; leg segments L: I-Leg- 1–6—55 –60, 95–105, 105–115, 120–125, 120–130, 95–105; II-Leg- 1–6—55 –60, 105–110, 95–105, 145–155, 180–190; III-Leg- 1–6—55 –65, 105–115, 105–115, 145–155, 180–195, 160–170; IV–Leg– 1–6—80 –90, 110–125, 120–130, 160–180, 195–215, 175–190.

Deutonymph. See Nocentini (1960), Tuzovskij et al. (2011).

Larva. Unknown.

Habitat. Lakes, running waters.

Hosts. Unionidae: Lamellidens marginalis (Lamarck) (Edwards & Vidrine 2013) .

Distribution. Europe: Hungary, Italy, Portugal, Poland, Russia, Ukraine (Szalay 1927, 1964; Ramazotti 1947; Nocentini 1960; Biesiadka 1972; Tuzovskij 1997; Tuzovskij et al. 2011), India (Majumder & Pal 1988).