Uchidastygacarus (Uchidastygacarus) primoryensis, Semenchenko, Ksenia A., 2010

Semenchenko, Ksenia A., 2010, Two new water mites species (Acariformes: Hydrachnidia) from interstitial waters of the Russian Far East, Zootaxa 2429, pp. 52-60 : 57-59

Uchidastygacarus (Uchidastygacarus) primoryensis sp. n.

( Figs. 22–29 )

Type series. Holotype: female (351-kas– IBSS), Russia, Primory Territory, Partizansky District, the Partizanskay River basin, the Tigrovaya River, N 43o11.401’; E 133o12.660’; depth about 1.2 m; substrates: stones, pebbles, sand, 5.08.2009, leg. K.A. Semenchenko, D.A. Sidorov. Paratype: female (395-kas– IBSS), Russia, Primory Territory, Lasovsky District, the Kievka River basin, the Lasovka River, N 43o22.570’; E 133o53.772’; depth about 1.2 m; substrates: stones, pebbles, coarse-grained sand, 3.08.2009, leg. K.A. Semenchenko, D.A. Sidorov.

Description. Female. Body flat and rounded. Dorsal and ventral shields punctate. Dorsal shield covering dorsum of idiosoma and overlapping dorsal furrow, with 5 pairs of setae: Vi, Oi, Hi, Sci and Li ( Fig. 22 ). Setae Si situated posteriorly in dorsal furrow. Setae Fp, Oi, Pi and Pe without glandularia, other idiosomal setae with glandularia.

Anterior margins of coxae I–III forming rounded edge transcending dorsum ( Fig. 23 ). Setae Se and its glandularium separated from each other. Setae Pi and Se situated close and posterior to genital field.

Genital field transversal with 3 pairs of acetabula approximately subequal in size and 4–5 lateral setae on each side ( Fig. 24 ). Gonoporus expanded posteriorly.

Capitulum with relatively long rostrum, its length about 1/4 of capitulum lengths ( Fig. 25 ).

Basal segment of chelicera with concave dorsal and nearly straight ventral side ( Fig. 26 ). Cheliceral stylet without teeth, with ridges basally.

Pedipalp with expanded femur and tibia, genu extremely reduced ( Fig. 27 ). Femur of pedipalp with 3 terminally feathered setae. Tibia of pedipalp bearing 1 short and stout biramous seta, one fork of which with 2 or 3 small tines ( Figs. 27–28 ). Surface of pedipalpal tibia in its proximal part with cell-shaped reticulation. Pedipalpal tarsus curved with proximal solenidion, 4 slender setae and 2 thick medial setae.

Tarsus of leg IV without claws, bearing 5 setae, terminal seta exceeding length of tarsus in 1.5 times ( Fig. 29 ).

Measurements (n=2). Length of body 422–468; width 376–422; length of dorsal shield 416–435, width of coxal shield (one side, midline to tip of condyle at insertion of leg IV) 126–138; length of genital field 53–56, width 90–100; diameter of genital acetabula (ac. 1–3): 9–10, 10–11, 11–13; length of capitulum 94–118, length of rostrum 20–30; length of cheliceral basal segment 78–81, length of cheliceral stylet 30–46; length of pedipalpal segments (P-1–5):?–10, 51–70, 10–13, 86–121, 62–90; length of leg segments: I-L- 1–6—38 –40, 45–52, 30–34, 34–38, 40–53, 47–64; II-L- 1–6—35 –47, 40–44, 32–37, 34–41, 43–54, 56–75; III-L- 1–6—37 – 51, 35–55, 27–34, 32–38, 38–52, 59–65; IV-L- 1–6—47 –51, 56–68, 38–41, 43–49, 44–71, 37–50.

Male. Unknown.

Differential diagnosis. The new species belongs to the akiyoshiensis -group proposed by Smith (1992) on the basis of the presence of a stout seta on the medial surface of the pedipalpal tibia, which is furcated with 2 or more tines (equal or unequal) or palmate. It is similar to two species from this group: Uchidastygacarus palmifer Imamura, 1959 and U. appalachianus Smith, 1992 . Length of body in U. primoryensis sp. n. female exceeding its width (422–468 and 376–422 respectively), the length of dorsal shield slightly shorter than the general body length (416–435), stout seta on pedipalpal tibia furcated, gonoporus of equal length and width. Female in U. palmifer has equal length and width of body (543), the length of the dorsal shield considerably shorter than the general body length (462), the stout seta on pedipalpal tibia palmate, gonoporus longer than broad ( Imamura 1959). Uchidastygacarus primoryensis sp. n. as well as U. appalachianus has the stout seta on pedipalpal tibia furcated into 3 or more tines ( Smith 1992). The main distinctive feature between these species is that the genital field of female U. primoryensis sp. n. has 3 pairs of acetabula approximately subequal in size whereas the genital field of female U. appalachianus has the third acetabula much larger than the anterior 2 pairs.

Etymology. The species epithet primoryensis is named after the region where it was collected (Primory Territory).

Habitat. Interstitial waters.

Distribution. Primory Territory, Far East of Russia.

Figures

FIGURES 22 – 23. Uchidastygacarus primoryensis sp. n., female: 22, idiosoma, dorsal view; 23, idiosoma, ventral view.

FIGURES 24 – 29. Uchidastygacarus primoryensis sp. n., female: 24, genital field; 25, capitulum (lateral view); 26, chelicera; 27, pedipalp, medial view; 28, thick seta on pedipalpal tibia; 29, leg IV. Scale bars = 100 µm for Fig. 29; 25 µm for Figs. 24 – 28.