Albaxona (Vietsaxona) steklyanukhaensis, Tuzovskij, 2018

Tuzovskij, Petr V., 2018, New water mite species of the genus Albaxona Szalay, 1944 (Acari, Hydrachnidia, Aturidae) from Russia, Zootaxa 4392 (1), pp. 179-195 : 192-193

Albaxona (Vietsaxona) steklyanukhaensis sp. n.

( Figs 44–52 )

Holotype: female, slide 507-Kas, Russia, Far East, Primorye Territory, Shkotovskiy District, Steklyanukha River, N43o 21.027’; E 132o27.723’, depth 0.3 m, substrates: pebbles, sand, 7 October 2010, leg. D. Sidorov and K. Semenchenko. The holotype is deposited in the collection of the Institute of Biology and Soil Science, Far Eastern Branch of Russian Аcademy of Sciences (Vladivostok).

Diagnosis. Female. Idiosoma elongate with convex lateral margins, setae Fch and Fp located on common platelet on each side, setae Si and Ci not associated with glandularia, posteriomedial muscle attachment scars on coxal plates IV not developed, excretory pore fused with dorsal shield; acetabular plates triangular with short rounded posterior end, setae and glandularia Se lying free, anterior genital sclerite long and fused with ventral shield, posterior genital sclerite lying free.

Description. Idiosoma oval. Dorsal shield elongate (L/W ratio 1.77), covering most of dorsal surface and bearing 5 pairs of setae: Oi, Oe, Hi, Li, Si ( Fig. 44 ). Setae Oi and Oe located in anterior half of dorsal shield, Hi a little distally to middle of shield, Li in distal portion of shield, and Si close to posteriolateral margins of shield. Setae Fch and Fp located on common platelet on each side. Setae Si and Ci not associated with glandularia. Setae Fch, Fp, Vi, Ve, He, Sci, Le, Ci, Pi and all pairs of slit organs located on soft membrane between dorsal and ventral shields: i1 and seta Vi placed on common sclerite on each side, i2 at level to Oe, i3 anterior to Sci, i4 anterior to Le, and i5 at level to Si. Setae Fch short, thick and serrate, other idiosomal setae thin, hair–like.

Ventral shield ( Fig. 45 ) broader than dorsal shield, anterior coxal plates slightly projecting beyond anterior margin of idiosoma, suture line between coxal plates II–III distinct developed only in their lateral parts. Seta Hv located near posteriolateral margin of coxal plate II, Ve laterally to coxal plates III, Sce medially to suture line between coxal plates III and IV, posteriomedial muscle attachment scar not developed. Setae Ci not associated with glandularia, close to Pi and both placed on common small transversal sclerite on each side caudally. Glandularium Se lying free on each side. Аnterior genital sclerite elongate (L/W ratio 3), fused with ventral shield, postgenital sclerite lying free. Аcetabular plates triangular, with a relatively broad, rounded posterior end and five fine setae each. Dorsal and ventral shields porous.

Capitulum ( Fig. 46 ) with a relatively long rostrum, dorsal hypostomal setae nearly three times longer than ventral ones. Chelicera with a large basal segment and a long, thin chela ( Fig. 47 ).

Pedipalp ( Fig. 48 ): P–1 relatively short with a single dorsodistal seta; P–2 ventral margin straight, with two dorsoproximal setae and three subequal dorsodistal setae; P–3 ventral margin slightly concave, with two dorsoproximal and two dorsodistal subequal setae, all these setae considerably shorter than dorsal margin of segment; P–4 longer than P-2, with straight ventral margin.

Shape and arrangement of setae on legs II–IV as shown in Figs 49–51 . Leg claws ( Fig. 52 ) thin, hook–like, with long ventral clawlet and short dorsal one, claw lamella not developed.

Measurements (n=1). Idiosoma L 408, W 295; dorsal shield L 378, W 215; acetabular plate L 72, W 42; capitulum L 78; chelicera: basal segment L 84, chela L 48; genital acetabula (ac.1–3) L: 12, 15, 15; pedipalpal segments (P-1–5) L: 18, 42, 30, 51, 19; leg segments L: II–Leg-1–6: 45, 36, 36, 48, 60, 65; III-Leg-1–6: 45, 36, 39, 51, 65, 72; IV–Leg-1–6: 78, 54, 66, 78, 90, 72.

Male. Unknown.

Differential diagnosis. The new species is similar to Albaxona (Vietsaxona) libera Kim & Chung 1996 , known from the male only from South Korea ( Kim & Chung, 1996). The male of A. libera is characterized by the following features: dorsal shield with convex posterior margin, II/III-Leg-5 with three to four distal thick setae ( Kim & Chung 1996), while in the female of A. steklyanukhaensis sp. n. dorsal shield with concave posterior margin, II/III-Leg-5 with six thick setae ( Figs 49–50 ).

Etymology. The species epithet “ steklyanukhaensis ” is derived from the name of river where it was collected (Steklyanukha).

Habitat. Running waters.

Distribution. Аsia ( Russia, Primorye Territory).

Figures

FIGURES 44–45. Albaxona steklyanukhaensis sp. n., female: 44, dorsal view; 45, ventral view. Scale bar: 100 µm.

FIGURES 46–52. Albaxona steklyanukhaensis sp. n., female: 46, capitulum, lateral view; 47, chelicera, lateral view; 48, pedipalp; 49, Leg II; 50, Leg III; 51, Leg-IV; 42, claw of leg IV. Scale bars: 46–48; 49–51 = 50µm; 52 = 25 µm.