Albaxona (Albaxona) primoryensis, 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 : 180-184

Albaxona (Albaxona) primoryensis sp. n.

( Figs 1–14 )

Type series. Holotype: male, slide 422- Kas , Russia, Far East , Primorye Territory , Partizanskiy District , Tigrovaya stream inflow of Partizanskaya River, N43o11,401’; E 133o12.660’, depth 0.3 m, substrates: stones, pebbles, sand, 12 June 2010 . Paratypes: 1 male (slide 421-Kas) and 1 female (slide 501- Kas) same data as holotype, leg. D. Sidorov and K. Semenchenko.

Аdditional material: 1 male (slide 9638- IBIW): Primorye Territory, Ussuri National Park, Komarovka River , depth 0.4 m; substrates: stones, pebbles, sand, 29 May 1984, leg. T. Vshivkova. The holotype and paratypes 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. Both sexes: Idiosoma elongate, with straight anterior margin, setae Si and Ci not associated with glandularia, posteriomedial muscle attachment scars on coxal plates IV present, excretory pore free; male: genital field fused with ventral shield, outline of acetabular plates distinct, their anterior margins with four to six pairs of setae forming a nearly straight transverse row, gonopore trapezoid, longer than wide, setae Se fused with ventral shield posteriolaterally; female: ventral shield and genital field separated, acetabular plates triangular each with a long narrow posterior projection, fused with posterior genital sclerite and each with a long narrow posterior projection, fused with posterior genital sclerite and with glandularia Se anterolaterally.

Description. Both sexes. Idiosoma oval. Dorsal shield covering most of dorsal surface, bearing 5 pairs of setae: Oi, Oe, Hi, Li, Si ( Fig. 1 ). 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 posterolateral margins of shield. Setae Si and Ci not associated with glandularia, other idiosomal setae associated with glandularia. Setae Fch, Fp, Vi, Ve, He, Sci, Le, Ci, Pi and all pairs of slit organs (i1–i5) located in soft interscutal 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 posterior to Le, and i5 at level to Si. Setae Fch short, thick and serrate, other idiosomal setae thin, hair–like.

Ventral shield ( Fig. 2 ) broader than dorsal shield, tips of anterior coxal plates reaching or slightly projecting beyond anterior idiosoma margin, suture line between coxal plates II–III distinct developed only in their lateral parts. Setae Hv located near posterolateral margin of coxal plates II, Ve laterally to coxal plates III, Sce medially to suture line between coxal plates III and IV, Pe associated with posteriomedial muscle attachment scars. Setae Ci and Pi close to each other and placed on a common small sclerite caudally on each side. Dorsal and ventral shield porous.

Capitulum ( Fig. 3 ) with a relatively long rostrum, dorsal hypostomal setae nearly three times longer than ventral hypostomal setae. Chelicera with large basal segment and long, thin chela ( Fig. 4 ).

Pedipalp ( Fig. 5 ): P–1 relatively short with a single dorsodistal seta; P–2 ventral margin straight, with two dorsoproximal setae and three unequal dorsodistal setae; P–3 with slightly concave ventral margin, with two dorsoproximal and two dorsodistal, approximately subequal setae, all these setae considerably shorter than dorsal margin of segment; P–4 slender, with three rather long, unequal ventral setae and two short dorsodistal setae. Shape and arrangement of setae on legs as shown in Figs 10–13 . Leg claws ( Fig.14 ) thin, hook–like, with long internal clawlet and short external spur, claw lamella not developed.

Male. Dorsal shield elongate (ratio length/width 1.58–1.76). Genital field fused with ventral shield, wider than long, suture line indistinct, outline of acetabular plates distinct with 9–11 pairs of long, fine setae, their anterior margins with four to six pairs of setae and forming a nearly straight transverse row, gonopore trapezoid, longer than wide ( Fig. 6 ).

Ejaculatory complex ( Fig. 7 ) with long anterior arms and comparatively short posterior ones, proximal chamber large with convex anterior margin, a pair of short proximal horns extending to anterior margin of proximal chamber. Excretory pore free, placed in space between genital field and posterior idiosoma margin.

Measurements (n=3). Idiosoma L 395–405, W 300–305, dorsal plate L 375–390, W 220–245; genital field L 48–60, W 125–138; genital acetabula (ac. 1–3) L: 18–20, 18–21, 18–20;capitulum L 78–84, chelicera basal segment L 96, chela L 60; pedipalpal segment (P1–5) L: 18–21, 36–42, 30–36, 48–54, 20–24; leg segments L: I- Leg-1–6: 30–36,30–36, 50–55, 60–72, 63–72, 65–72; II–Leg-1–6: 36–42, 30–36, 36–42, 49–50, 60–63, 60–66; III–Leg-1–6: 35–42, 35–43, 36–42, 48–51, 60–66, 63–70; IV–Leg-1–6: 72–84, 50–60, 75–80, 75–78, 78–87, 72– 75.

Female. Dorsal and ventral shield similar to those of male ( Fig.15–16 ). Аcetabular plates with five to six fine setae each, expanded anteriorly and strongly narrowed posteriorly, fused with postgenital sclerite and with sclerites bearing seta and glandularium Se anteriolaterally on each side. Аnterior genital sclerite elongate, fused with ventral shield, approximately three times longer than wide.

Measurements (n=1). Idiosoma L 415, W 318, dorsal plate L 408, W 235; acetabular plate L 90, W 54; genital acetabula (ac. 1–3) L: 15, 21, 21; capitulum L 90; chelicera: basal segment L 95, chela L 65; pedipalpal segments (P-1–5) L: 24, 39, 36, 54, 24; leg segments L: I-Leg-1–6: 30, 30, 48, 65, 65, 60; II–Leg-1–6: 35, 30, 42, 42, 60, 60; III–Leg-1–6: 35, 30, 36, 48, 65, 63; IV–Leg-1–6: 85, 54, 72, 72, 78, 72.

Differential diagnosis. The new species is similar to Albaxona orientalis Tuzovskij, 2011 described also from Primory Territory ( Tuzovskij 2011).The male and female of A. primoryensis sp. n. differ from the adult of A. orientalis by the structure of the genital area. The male gonopore of A. orientalis is triangular ( Fig. 8 ), the outline of the acetabular plates is indistinct; the female acetabular plates are with short anterior genital sclerites (L/W ratio 1.0–1.5), the acetabular plates are not fused with the posterior genital sclerite, glandularia Se are free ( Fig. 9 ). In contrast, the male gonopore in A. primoryensis sp. n. is trapezoid ( Fig. 6 ), the outline of the acetabular plates is distinct; the female acetabular plates have a long anterior genital sclerite (L/W ratio 3), the acetabular plates are fused to posterior genital sclerite and the glandularia Se are fused with the acetabular plates ( Fig. 16 )

Etymology. The species epithet “ primoryensis ” is derived from the name of the Territory where it was collected (Primory).

Habitat. Running waters.

Distribution. Аsia ( Russia, Primorye Territory).

Figures

FIGURES 1–2. Albaxona primoryensis sp. n., male: 1, dorsal view; 2, ventral view. Scale bar: 100 µm.

FIGURES 3–9. Albaxona primoryensis sp. n. and A. orientalis Tuzovskij, 2011: 3, capitulum, ventral view; 4, chelicera, lateral view; 5, pedipalp; 6, 8–9, posterior part of ventral view; 7, ejaculatory complex; 3–7, A. primoryensis sp. n., male; 8–9, A. orientalis; 8, male; 9, female. Scale bars: 3–7 = 50µm; 8–9 - 100 µm.

FIGURES 10–14. Albaxona primoryensis sp. n., male: 10, Leg I; 11, Leg II; 12, Leg III; 13, Leg- 4; 14, claw of Leg IV. Scale bars: 10–13 =50 µm; 14 = 20µm.

FIGURES 15–16. Albaxona primoryensis sp. n., female: 15, dorsal view; 16, ventral view. Scale bar: 100 µm.