Zschokkea orientalis, Tuzovskij, 2020

Tuzovskij, Petr V., 2020, Description of a new water mite of the genus Zschokkea Koenike, 1892 (Acari, Hydrachnidia, Hydryphantidae) from Northeastern Russia, Amurian Zoological Journal XII (2), pp. 132-137 : 133-136

Zschokkea orientalis sp. n.

http://zoobank.org/NomenclaturalActs/ 3FE921B2- 7B7A-4810-8F6F-62050FAF52BF

( Figs 1 -3: 1–13)

Type series. Holotype: male, slide 2884, Asia, Russia, Chukotka, Anadyr District, small tundra pool near settlement Markovo , 30 August 1981 . Paratypes: from the same locality as holotype, 1 female 10 July 1978 , 1 female 10 August 1981 . Additional material: Kamchatka Region, Ust-Kamchatsk District, sedge-sphagnum bog on the right bank of the Kamchatka river, 40 km upstream from Ust-Kamchatsk city near biological station “Raduga”, 2 females 21 June 1983, 1 female 24 June 1983, 1 male 26 June 1983, 1 male and 2 female 30 June 1983, 2 females 3 July 1983, 1 male 17 July 1983 and 1 female 21 August 1983.

Diagnosis. Idiosoma without dorsal and ventral platelets; medial eye small, surrounded by sclerotized ring; idiosoma papillae flat; second and third acetabula in trapezoid arrangement in male, and in female they form straight transverse row; medial and lateral margins of genital flaps convex in both sexes, number of genital setae without essential differences in both sexes; P–3 quadrate in lateral view, with five to eight dorsal setae.

Description. Both sexes. Color red. Idiosoma dorsal and ventral platelets completely absent ( Figs. 1 : 1, 2). Lateral eyes in capsules, anterior lens larger than posterior one on each side. Medial eye very small and surrounded by sclerotized ring ( Fig. 1 : 3). Number of idiosomal setae typical for the family Hydryphantidae ( Tuzovskij 1987) , trichobothria Fp and Oi not associated with glandularia, other idiosomal setae associated with glandularia. Idiosoma bears five pairs of lyriform organs, first four pairs (i1– i4) located dorsally, fifth pair (i5) ventrally. Idiosoma integument with flat papillae ( Fig. 1 : 4). Genital field with large flaps and three pairs of very small acetabula, which are located on extension each and all included into genital flap margins. Excretory pore unsclerotized.

Capitulum ( Fig. 2 : 5) with very short rostrum, mouth opening small. Chelicera basal segment with relatively large dorsal hump, crescent chela short ( Fig. 2 : 6). Pedipalp ( Fig. 2 : 7) moderately slender, setation: P–1, 1–2; P–2, 8–10; P–3, 5–8; P–4, 4 (all distally, two dorsally: one proximal fine and one peg-like distally, two ventral: proximal seta thickened basally, distal seta not thickened basally), P–5, 10 (proximal solenidion short, five pointed and four obtuse thick setae distally, Fig. 8). Pedipalpal genu (P– 3) quadrate in lateral view (L/H ratio 0.95–1.0). Legs stout, setae in low numbers, but strong and without swimming setae ( Fig. 2 : 9). Leg claws simple, hook-shaped, with supraclaw platelet each ( Fig. 2 : 10).

Male. Shape of coxal plates and genital field as shown in Fig. 2 : 2. Genital flaps broad (L/W ratio 2.05–2.30), with 14–21 long setae each (11–16 medial and 2–5 lateral), lateral margins well convex, medial margins straight or slightly convex; both posterior pairs of genital acetabula in trapezoid arrangement, third pair acetabula situated anterior and lateral to second ones, posteromedial extension with two setae (Fig. 3: 11). Ejaculatory complex proximal chamber large, oval, bearing a short curved horn apically; proximal arms massive, strongly curved, broadest basally, tapering gradually to apex, distal arms slightly developed (Fig. 3: 12).

Measurements (n = 5). Idiosoma L 800– 1000, W 700–800; medial eye D 9–11; genital flap L 160–195, W 70–85; cheliceral segments: base L 160–185, chela L 54–60; acetabula (ac. 1–3) D: 15–18, 18–24, 15–18; pedipalp segments (P–1–5) L: 39–50, 120–125, 70–80, 125–140; 40–42; legs segments L: I–Leg–1–6: 60–65, 115–125, 85–100, 120–130, 155–170, 205–245; II–Leg–1–6: 55–70, 100–130, 95– 100, 145–150, 180–190, 235–270; III–Leg–1– 6: 65–75, 85–105, 75–90, 125–140, 175–210, 190–205; IV–Leg–1–6: 120–150, 105–140, 115–130, 175–190, 185–205, 200–215.

Female. Genital flaps large, elongate (L/W ratio 2.6–2.7), with 14–22 relatively short setae each (10–17 medial and 2–7 lateral), lateral margins slightly convex, medial margins straight or slightly convex, second and third pairs of genital acetabula arranged in a straight transverse row, posteromedial extension with two setae (Fig. 3: 13).

Measurements (n = 7). Idiosoma L 810– 1500, W 625–1100; medial eye D 11–13; genital flap L 260–275, W 100–115; cheliceral segments: base L 180–230, chela L 55–70; acetabula (ac. 1–3) D: 18–25, 25– 30,18–25; pedipalp segments (P–1–5) L: 39–50, 120–125, 70–80, 125–140; 40–42; legs segments L: I–Leg–1–6: 60–90, 105– 145, 80–110, 115–150, 135–185, 150–185; II–Leg–1–6: 60–80, 110–140, 85–115, 120–170, 145–205, 180–210; III–Leg– 1–6: 65–85, 100–125, 90–110, 110–165, 145–205, 170–220; IV–Leg–1–6: 120–165, 115–155, 115–155, 155–220, 170–240, 175–240.

Differential diagnosis. The new species is similar to Z. oblonga and Z. langei ( Tuzovskij, 1976) . The present species is closely related to Z. oblonga ; however, the following clear differences can be found in the morphology of adults (character states of adults of Z. oblonga are given parenthesis after Lundblad 1927, Sokolov 1940 and Gerecke, Gledhill, Pešić, Smit 2016; 2016): the idiosoma dorsal and ventral platelets completely absent (present), the genital flaps medial margin straight or slightly convex (equally concave), the genital setae number without essential differences in both sexes (female genital setae less than in the males), P–3 with five to eight setae (four setae). The female of Zschokkea langei is characterized by the presence of idiosomal platelets, genital flaps with convex medial margins and straight lateral margins and with more numerous genital setae ( Tuzovskij 1976).

Figures

Fig. 1. Zschokkea orientalis sp. n., male: 1 — idiosoma, dorsal view; 2 — idiosoma, ventral view; 3 — medial eye; 4 — fragment of integument. Scale bars: 1–2 = 200 μm, 3–4 = 50 μm Рис. 1. Zschokkea orientalis sp. n., самец: 1 — иÃиосома, ÃорсаΛьная сторона; 2 — иÃиосома, вентраΛьная сторона; 3 — меÃиаΛьный гΛаз; 4 — фрагмент покрова. ШкаΛы: 1–2 = 200 μm, 3–4 = 50 μm

Fig. 2. Zschokkea orientalis sp. n., male: 5 — capitulum, lateral view; 6 — chelicera, lateral view;7 — pedipalp, lateral view; 8 — tarsus of pedipalp; 9 — I–Leg–4–6; 10 — claw of leg IV. Scale bars: 5–7, 9 = 100 μm, 8, 10 = 20 μm Рис. 2. Zschokkea orientalis sp. n., 5 — капитуΛум, боковой виÃ; 6 — хеΛицера, боковой виÃ; 7 — пеÃипаΛьпа, боковой виÃ; 8 — Λапка пеÃипаΛьпы; 9 — коΛено, гоΛень и Λапка ноги IV; 10 — коготок ноги IV. ШкаΛы: 5–7, 9 = 100 μm, 8, 10 = 20 μm