Hygrobates neosokolowi, Tuzovskij, 2020

Tuzovskij, Petr V., 2020, A new water mite species of the genus Hygrobates Koch, 1837 (Acari, Hydrachnidia, Hygrobatidae) from Russia, Amurian Zoological Journal XII (4), pp. 439-443 : 440

Hygrobates neosokolowi sp. nov.

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References/ 1D4EEBD9-BA07-4543- A6A9-F30F129DB045

( Figs 1–8)

Type material: Holotype: male, slide 6301, Russia, Primorsky Krai, Rakovka stream, 17 July 1978, leg. T. S. Vshivkova . Holotype is deposited in the collection of the Papanin Institute for Biology of Inland Waters (Borok, Russia) .

Diagnosis. Integument soft and finely striated; anterior coxal plates with short apodemes, posteromedial margin convex in shape; coxal plate IV trapezoidal with almost parallel anterior and posterior margin, medial margin in an obtuse angle; genital field with three pairs large genital acetabula and 24–25 pairs setae, posterior margin of genital plate of male deeply indented without median projection; P–2 with long rounded ventrodistal protrusion; P–4 ventral setae moderately separated in distal portion of segment.

Description

Male. Idiosoma oval and somewhat flattened dorsoventrally. Integument soft and finely striated ( Fig. 1). Trichobothria Fp, Oi and setae Pi not associated with glandularia, other idiosomal setae associated with glandularia. Setae Fch ( Fig. 2) much thicker than other idiosomal setae. Anterior coxal plates with short apodemes, posteromedial margin convexin shape ( Fig. 3). Coxal plate IV trapezoidal, with nose-like protruding medial margin.

Genital field ( Fig. 4) wider than long (L/W ratio 0.7), anterior margin slightly convex, with a small median protrusion, posterior margin deeply indented without median projection. Genital acetabula large in obtuse triangle, distance between ac–1 and ac–2, ac–2 and ac–3, and ac–1 and ac–3 less than length of any acetabulum. Genital field with 24–25 pairs setae, five pairs longer and thicker than other genital setae.

Pedipalp moderately long ( Fig. 5 ): P–1 short, with single dorsodistal seta; P–2 with five short, thick dorsal setae, ventral margin proximally nearly straight, distoventrally protruding in a long and slender projection with rounded tip, apically covered by a few denticles; P–3 with three dorsoproximal, two dorsodistal short, thick setae and single thin dorsodistal seta, ventral margin straight with denticles covering distal half of ventral surface; P–4 slender, longer than P–2 (P–4/P–2 L ratio 1.3), ventral setae subequal in length and moderately separated in distal portion of segment.

Legs—6, segmented, slender and without swimming setae. I–Leg–5 with two subequal rather long pointed distoventral setae ( Fig. 6 ); IV–Leg–4/5 with three short, thick unequal distal setae, IV–Leg–6 usually with two short, thick ventral setae ( Fig. 7 ). Claws of all legs with long external clawlet and short internal one, lamella well-developed with slightly concave ventral margin ( Fig. 8 ).

Measurements (n = 1). Idiosoma L 870; seta Fch L 90; coxal plates I + capitulum mL 265; coxal plates III+IV L 300, W 250; genital plate L 120, W 175; genital acetabula (ac–1–3) L/W 80–85/54–60, 102–105/48–54, 95–98/72–78; pedipalp segments (P–1–5) L: 42, 126, 108, 162, 48; leg segments L: I–Leg– 1–6: 60, 110, 115, 162, 168, 150; II–Leg–1–6: 65, 100, 120, 175, 190,?; III–Leg–1–6: 78, 108, 132, 210, 240, 192; IV–Leg–1–6: 145, 150, 175, 240, 270, 210.

Female. Unknown.

Differential diagnosis. The new species is similar to Hygrobates sokolowi Thor, 1927 . The male of the new species differs in genital field ( Fig. 4) with large genital acetabula occupying about one half of acetabular plate surface, distance between ac–1 and ac–3 less than length of any acetabulum, posteromedial in-

Figures

Figs 5–9. Hygrobates neosokolowi sp.n., male: 5 — pedipalp; 6 — I–Leg–4–6; 7 — IV–Leg– 4–6; 8 — leg claw. Scale bars: 5, 8 = 50 μm; 6, 7 = 100 μm. Hygrobates sokolowi (Thor, 1927), male: 9 — genital field. Scale bar: 50 μm Рис. 5–9. Hygrobates neosokolowi sp. n., самец: 5 — пеΔипаΛьпа; 6 — коΛено, гоΛень и Λапка ноги I; 7 — коΛено, гоΛень и Λапка ноги IV; 8 — коготок ног. ШкаΛы: 5, 8 = 50 μm; 6, 7 = 100 μm. Hygrobates sokolowi (Thor, 1927), самец: 9 — генитаΛьное поΛе. ШкаΛа: 50 μm