Hygrobates (Rivobates) primoryensis, . & . & P- & I- & - & -, 2017

Tuzovskij, Petr V., 2017, A new water mite species of the genus Hygrobates Koch, 1837 (Acari, Hydrachnidia, Hygrobatidae) from Far East of Russia, Ecologica Montenegrina 10, pp. 22-25 : 22-25

Hygrobates (Rivobates) primoryensis sp.n.

( Figs 1-10 )

Type material: Holotype: male, slide 4967, deposited in the collection of the Institute for Biology of Inland Waters ( Borok , Russia), Russia, Primory Territory, Komarovka river, 17.7. 1983, leg. T. S. Vshivkova . Paratypes: three males, one female collected from the same locality and data as holotype, and one female from the same locality, 28.10. 1983, leg. T. S. Vshivkova .

Diagnosis. Integument smooth; anterior coxal plates with short posterolateral apodemes, posteromedial margin convex in shape; coxal plate IV trapezoidal, medial margin forming an obtuse angle and with two medially-directed apodemes; genital field with 6-8 pairs of acetabula and 12-18 pairs setae, posterior margin of genital plate of male deeply indented; P-2 with short rounded ventrodistal protrusion; P-4 ventral setae located on the same level near middle of segment.

Description

Male. Idiosoma oval and somewhat flattened dorsoventrally. Idiosomal setae associated with glandularia, ecept for trichobothria Fp, Oi and setae Pi. Setae Fch ( Fig. 1 ) much thicker than other idiosomal setae. Ventral view: Fig. 2 . Coxal plate IV with two subcutaneous projections, in medial and posterior position.

Genital plate inverse heart-shaped, wider than long (L/W ratio 0.8-0.9), anterior margin convex to obtuse angle ( Figs 3-4 ).

Pedipalp ( Fig. 5 ): P-1 with a single dorsodistal seta; P-2 with six short, thick dorsal setae, ventral margin proximally concave, distoventrally protruding in a short rounded projection covered by a few denticles; P-3 with two dorsocentral, two dorsodistal short, thick setae and a single thin dorsodistal seta, ventral margin straight or slightly concave proximally, with a few denticles covering distal 2/3 of ventral surface; P-4 longer than P-2 (P-4/P-2 L ratio 1.24-1.42), ventral setae subequal in length and located on the same level near middle of segment.

I-Leg-5 with two subequal rather long distoventral setae ( Fig. 7 ); IV-Leg-4 with five short, thick unequal distal setae, IV-Leg-5 with four unequal distal thick setae, IV-Leg-6 usually with three thick setae ( Fig. 8 ). Claws of all legs with long external clawlet and short internal one, lamella with slightly concave ventral margin ( Fig. 9 ).

Measurements (n=4). Idiosoma L 430-600; seta Fch L 42-48; coxal plates I + capitulum mL 185- 215; genital plates L 125-135, W 135-170, cheliceral segments L: base 120-132, chela 72-78; pedipalp segments (P–1–5) L: 18-24, 71-73, 60-66, 95-102, 30-36; legs segments L: I-Leg-1-6: 48-55, 54-60, 84-90, 120- 125, 120-125, 115-120; II-Leg-1-6: 48-55, 54-60, 89-92, 115-125, 125-135, 105-125; III-Leg-1-6: 54-60, 60- 65, 95-102, 130-150, 150-170, 150-160; IV-Leg-1-6: 100-110, 84-95, 130-140, 170-185, 175-195, 160-175.

Female. Genital plate longer than width (L/W ratio 1.7-1.8), with 6-7 acetabula and 13-16 setae; medial margin straight and slightly indented anteriorly to middle of plate ( Figs 6 , 10 ). Anterior and posterior genital sclerites small and subequal in size. Excretory pore unsclerotized and located between flankig setae (Ci and Pi).

Measurements (n=2). Idiosoma L 480-650; seta Fch L 42-48; coxal plates I + capitulum mL 230- 235; genital plate L 114-120, W 65-68, cheliceral segments L: base 160-165, chela 90; pedipalp segments (P– 1–5) L: 30-35, 78-90, 65-72, 108-115, 36-42; legs segments L: I-Leg-1-6: 50-55, 65-70, 95-102, 135-140, 135- 140, 125-140; II-Leg-1-6: 50-55, 65-78, 95-102, 135-140, 145-152, 130-145; III-Leg-1-6: 54-60, 72-84, 105- 110, 155-165, 180-186, 160-170; IV-Leg-1-6: 114-120, 100-108, 150-165, 204-210, 215-225, 190-200.

Remarks. The present species is similar to Hygrobates ezoensis (Uchida, 1934) but differs in the following characters (character states of adult H. ezoensis given in parenthesis, data from Matsumoto et al. 2005): integument smooth (finely striated); coxal plate IV with two medial projections, Fig. 2 (without projections); anterior and posterior genital sclerites in females relatively narrow, Figs 6 , 10 (wide, Fig. 11 ), posterior margin of the genital plate of male deeply indented, Figs 3-4 (with straight to convex posterior margin and without the indentation, Fig. 12 ); P-2 with a short rounded projection, Fig. 5 (with tapering, pointed ventral projection, Fig. 13 ).

Ethymology. The species is named after the Primory Territory where it was collected.

Habitat. Running waters.

Distrbution. Asia, Russia, Far East, Primory Territory.

Figures

Figure 13. Hygrobates (Rivobates) ezoensis: 13 – pedipalp (after Matsumoto et al. 2005).

Figures 1-6. Hygrobates (Rivobates) primoryensis sp.n.: 1 – seta Fch, 2 – ventral view, 3-4, 6 – genital field, 5 – pedipalp; 1-5 – male, 6 – female. Scale bars: 1, 5 = 50 μm, 2-4, 6 = 100 μm

Figures 7-10. Hygrobates (Rivobates) primoryensis sp. n.: 7 – I-Leg-4-6, 8 – IV-Leg-4-6, 9 – leg claw; 10 – genital field; 7-9 male, 10 – female. Scale bars: 7, 8, 10 = 100 μm, 9 = 50 μm.

Figures 11-12. Hygrobates (Rivobates) ezoensis: 11-12 – genital field, 11 – female, 12 – male (after Matsumoto et al. 2005).