Unionicola inusitata Koenike, 1914

Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2015, Water mites of the genus Unionicola Haldeman, 1842 (Acari, Hydrachnidia, Unionicolidae) in Russia, Zootaxa 3919 (3), pp. 401-456 : 430-432

Unionicola inusitata Koenike, 1914

( Figs 24A–D , 25A–D )

Material examined. 3 males, 8 females (free-swimming): Russia, Samara Province, Stavropol District, National natural Park “Samarskaya Luka”, Gusinoe Lake, July–September 1992, leg. P.V. Tuzovskij.

Diagnosis. Adults. Dorsum with two pairs of small unequal platelets; coxal plates III+IV elongated with straight medial margin; P-3 with long laterodistal seta and relatively short dorsodistal seta, P-4 with three unequal ventral tubercles, P-5 moderately long with slightly concave ventral margin; anterior genital plates of female large, without subcutaneous projections; genital plates of male relatively narrow fused to each other by posterior ends only; swimming setae on IV-Leg-5 little shorter than IV-Leg-6; claws of legs I thick, hook-like, claws of legs II–IV thin, sickle-shaped.

Description. Both sexes. Dorsum with two pairs of small unequal platelets ( Fig. 24A ), anterior platelets relatively large, elongate; posterior platelets oval or circular and considerably smaller than anterior ones.

Anterior and posterior coxal groups ( Fig. 24B ) divided by relatively narrow interspace. Apodemes of first coxal group rather long and well extending beyond to anterior margin of third coxae. Coxal plates III+IV elongated (L/W ratio 1.4–1.6) with straight medial margin. Surface of all coxal plates with reticulations. Genital acetabula relatively small and occupy less than half of area of each plate. Sclerites, bearing setae and glandularia Le, larger than sclerites bearing other idiosomal setae.

Pedipalps ( Fig. 25A ) moderately long, first three segments and proximal portion of tibia expanded dorsoventrally. P-2 with five short subequal dorsal setae, P-3 with one long laterodistal and one relatively short dorsodistal setae; P-4 tapering distally, with two unequal ventral tubercles in distal half of segment and each bearing thin short seta and one ventrodistal tubercle bearing short peg-like seta, and with one thin dorsoproximal seta; P-5 moderately long with slightly concave ventral margin.

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. 25B ): one on telofemur, three on genu and on tibia. Swimming setae of II-Leg shorter than swimming setae on legs III–IV; swimming setae on IV-Leg-5 shorter than IV-Leg-6, the last with two thick setae. Claws of legs I ( Fig. 25C ) thick, hook-like with two unequal clawlets; claws of legs II–IV sickle-shaped with short dorsal clawlet and long ventral one ( Fig. 25D ).

Female. Anterior genital plates large, without anterior subcutaneous projections; both medial spines on anterior plates and anteromedial spine on posterior plate equal in length on each side ( Fig. 24C ). Posterior plates relatively small with 4–5 short, thin setae each.

Measurements (n=8). Idiosoma L 785–900; coxae III+IV L 275–315, W 200–225; anterior dorsal platelets L 50–60, W 15–25; posterior dorsal platelets L 18–25, W 12–18; anterior genital plates L 125–140, W 125–170; posterior genital plates L 100–105, W 135–140; pedipalpal segments (P-1–5) L: 25–35, 95–125, 48–65, 95–100, 65–75; leg segments L: I-Leg- 1–6—70 –90, 155–205, 160–180, 240–255, 160–190, 170–180; II-Leg- 1–6—70 –90, 195–205, 185–195, 270–285, 285–295, 235–255; III-Leg- 1–6—70 –85, 160–170, 150–165, 185–195, 225–240, 185–205; IV-Leg-1–6—105–125, 160–175, 185–205, 235–245, 315–325, 315–325, 275–285.

Male. Genital plates ( Fig. 24D ) wide, fused to each other by posterior ends, usually with 8–11 thin setae on each side, in additional onepair of genital setae located on soft integument.

Measurements (n=3). Idiosoma L 675–775; coxae III+IV L 250–275, W 185–195; anterior dorsal platelets L 50–65, W 15–20; genital field L 160–175, W 185–190; pedipalpal segments (P-1–5) L: 25–30, 85–95, 35–45, 85–90, 55–65; leg segments L: I-Leg- 1–6—60 –70, 125–135, 160–170, 210–225, 155–165, 155–165; II-Leg- 1–6—60 –70, 135–145, 170–200, 250–275, 250–265, 210–225; III-Leg- 1–6—60 –70, 110–125, 135–165, 175–200, 210–225, 175–190; IV-Leg-1–6—100–115, 130–140, 185–195, 235–245, 305–315, 260–270.

Deutonymph. See Hevers (1979).

Larva. See Hevers (1980).

Habitat. Lakes, reservoirs, ponds, running waters.

Hosts. Unionidae : Unio tumidus Philipsson , U. crassus Philipsson ( Hevers 1980) .

Distribution. Europe ( Viets 1936, 1956; Viets 1978). This species is reported from Russia for the first time.

Figures

FIGURES 24 A – D. Unionicola inusitata, adults: A, dorsal plates; B, coxal plates; C – D, genital field; A – C, female; D, male. Scale bars = 100 Μm.

FIGURES 25 A – D. Unionicola inusitata, female: A, pedipalp, lateral view; B, IV-Leg- 4 – 6; C, claw of leg I; D, claw of leg IV. Scale bars: A, C – D = 50 Μm; B = 100 Μm.