Unionicola setipes Sokolow, 1931

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 : 438-440

Unionicola setipes Sokolow, 1931

( Figs 32A–E , 33A–D )

Material examined. 11 females, Russia: Primory Territory, Khankaysky District, Khanka Lake, near Sivakovka, from mantle cavity of Sinanodonta sp., 28.05.2010, leg. M.B. Shedko.

Diagnosis. Adults. Dorsum with two pairs of small oval platelets; coxal plates III+IV slightly longer than their width with straight medial margin; P-3 with two long (proximal and distal) setae, P-4 slightly tapering distally, with three short unequal tubercles, P-5 rather long, with four unequal distal spines; each anterior genital plates of female with long anterior subcutaneous accretion and two unequal inner spines, each posterior plate with short, thin inner seta; genital plates of male separate crescent-shaped; legs II–IV with many swimming setae; claws of legs sickleshaped with short dorsal clawlet and long ventral one.

Description. Both sexes. Dorsum with two pairs of small oval platelets ( Fig. 32A ). Anterior and posterior coxal groups ( Fig. 32B ) divided by narrow interspace, sclerites, bearing setae and glandularia Le, larger than sclerites bearing other idiosomal setae. Apodemes of first coxal group long and well extending beyond to anterior margin of third coxae. Coxal plates III+IV slightly elongate (L/W ratio 1.25) with straight medial margin. Surface of all coxal plates with reticulations.

Pedipalps ( Fig. 32C ) short and stocky: P-2 with four setae; P-3 with two long (proximal and distal) setae; P-4 slightly tapering distally, with three unequal tubercles two of which bearing seta, lateral tubercle longer and more rounded distally; P-5 rather long, with concave ventral margin and four distal unequal spines.

Legs long, last segments more slender; all segments, except trochanter, cylindrical; legs II–III with swimming setae on two to five segments; 3–4 swimming setae on IV-L-3, 8–9 on IV-L-4 and 4-6 on IV-L-5 ( Figs 33 A-B). Claws of legs I–IV thin, sickle-shaped with short dorsal clawlet and long ventral ( Figs 33C–D ).

Female. Genital acetabula relatively small and occupy less than half of area of anterior plates and about half of area of posterior plates. Anterior genital plates with long anterior subcutaneous projections, two unequal acetabula, two unequal inner spines and two to three thin setae each ( Fig. 32D ). Posterior plates more or less triangular, with three unequal acetabula and five short, thin setae.

Measurements (n=2). Idiosoma L 1258–1310; coxae III+IV L 455–462, W 363–370; anterior dorsal platelets L 64–66, W 37–39; posterior dorsal platelets L 72–79, W 46–53; anterior genital plates L 100–125, W 152–171; posterior genital plates L 120–132, W 106–125; pedipalpal segments (P-1–5) L: 30–39, 138–160, 100–110, 165–170, 92–93; leg segments L: I-Leg-1–6—125–138, 230–237, 224–231, 376–382, 323–325, 283–350; II-Leg- 1–6—125–132, 257–277, 290–297, 442–455, 475–488, 369–370; III-Leg-1–6—130–132, 224–237, 264–270, 389–396, 448–462, 356–358; IV-Leg-1–6—204–211, 257–264, 317–330, 462–464, 574–600, 383–389.

Male. Idiosoma L 1350. Genital plates separated crescent-shaped, of equal width anteriorly and posteriorly, each with five unequal acetabula ( Sokolow 1931, 1940) ( Fig. 32E ).

Deutonymph. Unknown.

Larva. Unknown.

Habitat. Lakes, rivers.

Hosts. Unionidae : Cristaria plicata (Leach) ( Sokolow 1931, 1940) and Sinanodonta sp. (this study).

Distribution. Russia (Primory Territory) ( Sokolow 1940).

Figures

FIGURES 32 A – E. Unionicola setipes, adults: A, dorsal plates; B, coxal plates; C, pedipalp; D – E, genital field; A – D, female; E, male (after Sokolow, 1931). Scale bars = 100 Μm.

FIGURES 33 A – D. Unionicola setipes, female: A, I-Leg- 1 – 4; B, I-Leg- 5 – 6; C, claw of leg I; D, claw of leg IV. Scale bars: A – B = 100 Μm; C – D = 25 Μm.