Arrenurus (Arrenurus) primoryensis, Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2011

Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2011, New water mite species of the genus Arrenurus Dugs, 1834 (Acariformes, Hydrachnidia, Arrenuridae) from the Far East of Russia, Zootaxa 3037, pp. 1-20 : 9-11

Arrenurus (Arrenurus) primoryensis sp. n.

( Figs. 17–21 )

Type series. Holotype: male (9644– IBIW); Russia, Primory Territory, Lesozavodsky District, Ussuri River basin, small lake, 1 km from Gornye Kluchi, N 4515.490'; E 13330.195'; depth 50–70 cm; 10.08.2006, leg. K.A. Semenchenko, D.A. Sidorov.

Description. Male. Idiosoma wide (ratio L/ W 1.1), with short cauda ( Fig. 17 ); anterior margin between setae Fch concave, lateral margins convex. Dorsal shield indented laterally and with two pairs of small humps and bearing two pairs of setae (Oi, Hi) in the anterior half; Sci very short with blunt tip situated on somewhat rounded humps near middle of shield; setae and glandularia Li well separated, setae Li placed on separate humps in posterior half of shield, glandularia Li open on small tubercles near distal end of shield. Dorsal furrow passing onto sides of idiosoma at base of pygal lobes. Setae Fp, Oi and Pi without glandularia, other idiosomal setae associated with glandularia. Setae Ve, Oe, He, Sce and Se located along lateral margins of the idiosoma, and Le on the pygal lobes. Distance between setae Oi–Oi and Sci–Sci approximately subequal and nearly two times shorter than distance between setae Hi–Hi. Petiole large, narrowed anteriorly, widest distally to the middle, and two short distal serrate pointed processes; ligulate process elongate and narrow, slightly indented distally, and located in posterior half of petiole; hyaline membrane not developed. Setae Pi and Si close to each other and located caudally, Pi longer than petiole.

Anterolateral corners of coxal plates I and II pointed and extending beyond of the anterior idiosoma margin ( Fig. 18 ). Coxal plates I fused to each other medially, suture line between them developed only in theirs anterior half. Medial margin of coxal plate III twice shorter than medial margin of coxal plate IV, anterolateral corner of coxal plates III and lateral projection of coxal plate IV with rounded tips, the latter extending beyond the lateral idiosoma margin. Gonopore small and elongate, acetabular plates long and narrow, with rather numerous acetabula and one or two lateral setae each. Excretory pore open near of the petiole base. Setae Hv situated near posterolateral margin of coxal plates II, Pe located beyond of acetabular plates, seta and glandularia Se well separated and located on pygal lobes, Ci longer than Si.

Pedipalp stocky ( Fig. 19 ): P-1 short with a single dorsodistal seta; P-2 thick, with four unequal setae (one dorsoproximal, one dorsodistal, one mediodistal and one ventrodistal); P-3 relatively short, with two unequal lateral setae (internal and external); P-4 relatively long, with stout curved and pointed ventrolateral seta, two thin relatively long dorsodistal setae and two short distal setae; P-5 with a single solenidion, four thin setae and three spines (proximal spine pointed, two distal spines with rounded tips).

Tibia of legs II, genu and tibia of legs III and IV with swimming setae; IV–Leg-4 ( Fig. 20 ) with long curved distal projection bearing seven setae, IV–Leg-5 shorter than IV–Leg-4 and IV–Leg-6; IV–Leg claws ( Fig. 21 ) with two nearly subequal pointed denticles, claw lamella moderately developed with convex ventral margin.

Measurements, n=1. L of idiosoma (except petiole) 885, W 810; L of dorsal shield 675, W 485; distance between setae Oi–Oi 160, distance between setae Hi–Hi 410, distance between setae Sci–Sci 235, distance between setae Li–Li 135; L of petiole 235, W 100; distance between medial margins of coxal plates IV 35; L of basal segment of chelicerae 260, L of cheliceral stylet 185; L of pedipalpal segments (P-1–5): 37, 100, 80, 125, 50; L of leg segments: I–Leg- 1–6—65, 110, 150, 170, 150, 200; II–Leg- 1–6—80, 135, 150, 195, 180, 205; III–Leg-1–6—110, 160, 150, 200, 200, 200; IV–Leg-1–6—160, 200, 190, 310, 150, 210; L of distal projection of IV–Leg-4 85.

Female. Unknown.

Differential diagnosis. The male of new species is similar to Arrenurus distinctus Marshall, 1919 , A. liberatus Walter, 1929 and A. confines Lundblad, 1969 . The idiosoma of the male A. distinctus is longer (L = 1200 µm), the distal processes of the petiole elongate, wide with rounded tips ( Marshall 1919; Sokolow 1931, 1940). In contrast, the male of A. primoryensis sp. n. is shorter (L = 885 µm), the distal processes of the petiole short, narrow and pointed. The petiole bears one pair setae (Pi?), and third pairs of setae (Sci) on dorsal shield thin and long in males of A. liberatus and A. confinis , ( Cook 1967, Lundblad 1969); in contrast, the petiole without setae, and the third pair of setae on dorsal shield thick and short in the male A. primoryensis sp. n.

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

Habitat. Standing waters.

Distribution. Asia ( Russia: Far East, Primory Territory).

Figures

FIGURES 17 – 18. Arrenurus primoryensis sp. n., male: 17, idiosoma, dorsal view; 18, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 19 – 21. Arrenurus primoryensis sp. n., male: 19, pedipalp; 20, telofemur, genu, tibia and tarsus of leg IV; 21, claw of leg IV. Scale bars = 100 µm for Fig. 20; 50 µm for Figs. 19, 21.