Albaxona (Albaxona) sidorovi, 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 : 184-188

Albaxona (Albaxona) sidorovi sp.n.

( Figs 17–28 )

Type series. Holotype: female, slide 424- Kas , Russia, Far East , Primorye Territory , Partizanskiy District , Tigrovaya stream inflow of Partizanskaya River, N43o 11,401’; E 133o12.660’, depth 0.3 m, substrates: stones, pebbles, sand, 12 June 2010 . Paratype: 1 female (slide 423- Kas) collected in the same locality and data as holotype, leg. D. Sidorov and K. Semenchenko.

Аdditional material: 1 female (slide 6311): Primorye Territory, Ussuri National Park, Komarovka River , depth about 0.4 m; substrates: stones, pebbles, sand, 25 May 1984, leg. T.S. Vshivkova. The holotype and paratype are deposited in the collection of the Institute of Biology and Soil Science , Far Eastern Branch of Russian Аcademy of Sciences ( Vladivostok ); additional material is deposited in the collection of the Papanin Institute for Biology of Inland Waters (Borok, Russia).

Diagnosis. Female. Idiosoma elongate with convex lateral margins, setae Si not associated with glandularia, posteriomedial muscle attachment scars on coxal plates IV not developed, P-4 ventral setae on placed near middle of segment, excretory pore free; acetabular plates more or less triangular without posterior projections, setae Se free, Ci associated with glandularia and situated together with Pi on a small transversal sclerite on each side; anterior genital sclerite fused with ventral shield, twice as long as wide, posterior genital sclerite lying free.

Description. Idiosoma oval. Dorsal shield covering nearly all dorsal surface, bearing 5 pairs of setae: Oi, Oe, Hi, Li, Si ( Fig. 17 ). 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 very close to posteriolateral margins of shield. Trichibothria Fp and Oi, setae Si and Pi without glandularia, others idiosomal setae associated with glandularia. Setae Fch, Fp, Vi, Ve, He, Sci, Le, Ci, Pi and all slit organs located in soft interscutal membrane between dorsal and ventral shields: i1 and seta Vi placed on common sclerite on each side, i2 approximately at level and laterally to Oe, i3 anterior to Sci, i4 posterior to Le, and i5 at level to Si. Setae Fch short, thick and serrate, other idiosomal setae thin, hair–like.

Ventral shield ( Fig. 18 ) broader than dorsal shield, anterior coxal plates reaching or slightly projecting beyond anterior margin of idiosoma, suture line between coxal plates II–III distinctly developed only in their lateral parts. Seta Hv located near posterolateral margin of coxal plate II, Ve laterally to coxal plates III, Sce medially to suture line between coxal plates III and IV, Pe free, posteromedial muscle attachment scar not developed. Setae Ci associated with rudimentary glandularia, close to Pi and both placed on a common small transversal sclerite caudally on each side. Glandularium Se free on each side. Аnterior genital sclerite fused with ventral shield, twice as long as wide. Posterior genital sclerite lying free. Аcetabular plates ( Figs 19–20 ) more or less triangular, expanded anteriorly, narrowed posteriorly without posterior projection, with three to seven fine setae each. Dorsal and ventral shields porous.

Capitulum ( Fig. 21 ) with relatively long rostrum, dorsal hypostomal setae nearly three times longer than ventral ones. Chelicerae with large basal segment and rather long, thin chela ( Fig. 22 ).

Pedipalp compact ( Fig. 23 ): 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 straight, with 2 dorsoproximal and 2 dorsodistal approximately subequal setae, all these setae considerably shorter than dorsal margin of segment; P–4 longer than P-2, with three unequal ventral setae, middle seta is much longer than both other setae.

Shape and arrangement of setae on legs as shown in Figs 24–27 . Leg claws ( Fig. 28 ) thin, hook–like, with long internal clawlet and short external spur, claw lamella not developed.

Measurements (n=3). Idiosoma L 340–395, W 285–295, dorsal plate L 335–350, W 200–230; acetabular plate L 55–60, W 36–45; genital acetabula (ac. 1–3) L: 15–17, 16–19, 15–17; capitulum L 66–72; chelicera: basal segment L 95–100, chela L 39–48; pedipalpal segments (P-1–5) L: 18–22, 40–42, 30–32, 50–52, 16–18; leg segments L: I-Leg-1–6: 30–32, 30–39, 42–51, 60–64, 60–67, 57–60; II–Leg-1–6: 35–38, 30–35, 36–42, 42–48, 48–60, 54–70; III-Leg-1–6: 38–42, 30–38, 36–41, 45–48, 57–61, 54–67; IV–Leg-1–6: 72–83, 48–58, 63–67, 65– 71, 75–87, 65–77.

Male. Unknown.

Differential diagnosis. The new species is similar to Albaxona lunata Kim & Chung, 1996 known from the male only from South Korea ( Kim & Chung 1996). The setae Ci in the both species are associated with glandularia. The male of A. lunata is characterized by the following features: dorsal shield bearing four pairs of glandularia (setae Se associated with glandularia), ventral shield with a crescent-shaped ornamentation in front of the genital field ( Kim & Chung 1996), while in the female of A. sidorovi the dorsal shield ( Fig. 17 ) bears three pairs of glandularia (setae Se not associated with glandularia), ventral shield without a crescent-shaped ornamentation in front of the genital field.

Remarks. The record of A. lunata in the Far East of Russia ( Jubertie et al. 2016) needs confirmation.

Etymology. The species is named after Dr. Dmitry Sidorov.

Habitat. Running waters.

Distribution. Аsia ( Russia, Primorye Territory).

Figures

FIGURES 17–18. Albaxona sidorovi sp. n., female: 17, dorsal view; 18, ventral view. Scale bar: 100 µm.

FIGURES 19–23. Albaxona sidorovi sp. n., female: 19–20, acetabular plate; 21, capitulum, lateral view; 22, chelicera, lateral view; 23, pedipalp, lateral view. Scale bars: 19–22 = 50 µm; 23 = 20 µm.

FIGURES 24–28. Albaxona sidorovi sp. n., female: 24, Leg I; 25, Leg II; 26, Leg III; 27, Leg- IV; 28, claw of leg IV. Scale bars: 24–27 = 50 µm; 28 = 20µm.