Arrenurus (Arrenurus) hebraeus, 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 : 11-13

Arrenurus (Arrenurus) hebraeus sp. n.

( Figs. 22–26 )

Type series. Holotype: male (9643– IBIW); Russia, Jewish Autonomous Area, Leninsky District, Bidghan River basin, Ungun River, 12 km from Preobrazhenovka, N 4806.200'; E 13203.629'; depth up to 30 cm; substrates: stones, coarse-grained sand, 18.07.2005, leg. K.A. Semenchenko, D.A. Sidorov.

Description. Male. Idiosoma wide (ratio L/ W 1.17) and with very short cauda ( Fig. 22 ); anterior margin between setae Fch concave, lateral margins convex, with rather wide anterolateral strip near anterior end of dorsal shield on each side of dorsum. Dorsal shield expanded proximally with convex anterior margin, bearing three pairs of setae (Oi, Hi and Sci) in anterior half, setae and glandularia Sci and Li located on more or less rounded separate humps; setae and glandularia Li well separated, setae Li placed on humps distally to middle of shield, and glandularia Li opens on small tubercles near distal end of shield. Dorsal furrow passing onto sides of idiosoma at base of pygal lobes. Setae Ve, Oe, He and Sce located along lateral margins of the idiosoma, and setae Le on pygal lobes; Fp, Oi and Pi without glandularia, other idiosomal setae associated with glandularia. Distance between setae Oi–Oi and Sci–Sci approximately subequal and nearly twice shorter than distance between setae Hi–Hi. Petiole relatively large, narrowed proximally, widest near middle, with slightly convex distal margin and bearing two short distally pointed serrate processes; ligulate process relatively short, located posteriorly, distal margin straight; hyaline membrane not developed. Petiole and setae Pi approximately equal in length, Si considerably longer than Pi.

Anterolateral corners of coxal plates I and II pointed, not reaching to anterior idiosoma margin ( Fig. 23 ). Coxal plates I fused to each other medially, distinct suture line present only in the anterior half. Medial margin of coxal plate III 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 rather wide and extending onto dorsal sides of the idiosoma, with numerous acetabula and four fine setae (two anteromedial setae, one posteromedial seta and one posterolateral seta each). Excretory pore open on small tubercle near of the petiole base. Setae Hv situated near posterolateral margin of coxal plates II, Pe beyond acetabular plates, seta and glandularia Se slightly separated and placed on pygal lobes. Setae Si and Ci close to each other and located caudally, Ci shorter than Si.

Pedipalp stocky ( Fig. 24 ): P-1 short with a single dorsodistal seta; P-2 thick with one dorsoproximal seta, two dorsodistal setae and 1 ventrodistal seta; P-3 relatively short with two approximately subequal setae (internal and external); P-4 relatively long with stout pointed and rather long ventrolateral seta, two thin relatively long dorsodistal and two short distal setae; P-5 with a single solenidion, four thin setae and three spines: proximal spine is 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 with long distal projection which bearing four setae ( Fig. 25 ); IV–Leg-4 considerably longer than IV–Leg- 5 and IV–Leg-6; IV–Leg claws ( Fig. 26 ) with 2 subequal pointed denticles, claw lamella moderately developed with slightly convex ventral margin.

Measurements, n=1. L of idiosoma (except petiole) 1115, W 950; length of petiole 200, W 175; L of dorsal shield 800, W 660; distance between setae Oi–Oi 260, distance between setae Hi–Hi 525, distance between setae Sci–Sci 250, distance between setae Li–Li 135; distance between medial margins of coxal plates IV 50; L of basal segment of chelicera 160, L of cheliceral stylet 100; L of pedipalpal segments (P-1–5): 37, 95, 80, 125, 50; L of leg segments: I–Leg-1–6—100, 135, 160, 200, 175, 285; II–Leg-1–6—100, 160, 175, 225, 210, 285; III–Leg-1–6— 110, 175, 185, 250, 225, 285; IV–Leg-1–6—200, 225, 255, 375, 160, 200, L of distal projection of IV–Leg-4 90.

Female. Unknown.

Differential diagnosis. The new species is similar to A. primoryensis sp. n. The new species is characterized by the following features: the dorsal shield of the male expanded proximally with convex anterior margin, anterolateral strips present, the ligulate process wide with straight distal end, acetabular plates rather wide and extending onto laterodorsal sides of the idiosoma, IV–Leg-4 longer than IV–Leg-5 + IV–Leg-6. In contrast, the dorsal shield of the male A. primoryensis sp. n. is narrowed proximally with straight anterior margin, anterolateral strips not developed, ligulate process narrow with concave distal margin, acetabular plates narrow and only reaching lateral sides of the idiosoma, IV–Leg-4 shorter than IV–Leg-5 + IV–Leg-6.

Etymology. The species epithet hebraeus is named after the Latin name of the region where it was collected (Jewish Autonomous Area).

Habitat. Running waters.

Distribution. Asia ( Russia: Far East, Jewish Autonomous Area).

Figures

FIGURES 22 – 23. Arrenurus hebraeus sp. n., male: 22, idiosoma, dorsal view; 23, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 24 – 26. Arrenurus hebraeus sp. n., male: 24, pedipalp; 25, telofemur, genu, tibia and tarsus of leg IV; 26, claw of leg IV. Scale bars = 100 µm for Fig. 25; 50 µm for Figs. 24, 26.