Arrenurus (Arrenurus) neodaubihensis, 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 : 14-17

Arrenurus (Arrenurus) neodaubihensis sp. n.

( Figs. 27–34 )

Type series. Holotype: male (9650– IBIW); Russia, Primory Territory, Anuchinsky District, Arsenyevka River basin, small lake near Kornilovsky bridge, N 4307.757'; E 13313.280'; substrates: detritus, 17.09.2008, leg. K.A. Semenchenko, D.A. Sidorov. Paratypes: 1 male (9649– IBIW) and 2 females (9648– IBIW; 484-kas– IBSS), same data as holotype.

Description. Male. Idiosoma ( Fig. 27 ) elongate (ratio length/width 1.39–1.44) and with moderately developed cauda; anterior margin between setae Fch slightly concave, lateral margins convex; pygal lobes well developed and directed posterolaterally, with concave inner and convex outer sides. Dorsal furrow passing onto sides of idiosoma at base of pygal lobes. Dorsal shield with convex anterior margin, bearing two pairs of setae (Oi and Hi) in anterior half; setae and glandularia Sci well separated and located on well developed single median hump near middle of shield. Distal portion of cauda bearing petiole and four pairs of setae (Li, Le, Si and Pi); Pi shorter than petiole, Si longer than Pi, setae and glandularia Li separated, setae Li close to each other and placed on single small hump near distal end of shield. Setae Fp, Oi and Pi without glandularia, other idiosomal setae associated with glandularia; Ve, Oe, He and Sce located along lateral margins of the idiosoma, and Le on pygal lobes. Distance between glandularia Hi–Hi and Sci–Sci approximately subequal and nearly three times as long as distance between bases of setae Oi–Oi and Sci–Sci. Petiole large and narrowed anteriorly, widest distally to middle, with slightly convex distal end, ligulate process small, concave distally, and slightly extending beyond of the posterior margin of the petiole; ventral appendix of petiole rather large with small posteromedian projection and well extending beyond of the posterior margin of the petiole; hyaline membrane absent.

Anterolateral corners of coxal plates I and II pointed and not reaching to anterior margin of the idiosoma ( Fig. 28 ). 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; lateral projection of coxal plates IV extending beyond the idiosoma proper. Gonopore small, acetabular plates narrow with rather numerous acetabula, two short anteromedial setae and one long posterolateral seta each. Excretory pore lying on a small tubercle halfway between genital area and petiole. Setae Hv situated near posterolateral margin of coxal plates II, Pe located on small humps beyond acetabular plates,

seta and glandularia Se well separated and located on pygal lobes; Ci very long, located laterally to the petiole bases.

Chelicera ( Fig. 29 ) stout, basal segment with long, thin dorsodistal projection, cheliceral stylet pointed, thickened proximally.

Pedipalp stocky ( Fig. 30 ): P-1 short with a single dorsodistal seta; P-2 thick with slightly concave ventral margin, with three dorsal and two-five ventrolateral distal setae; P-3 relatively short with two approximately subequal lateral setae (internal and external); P-4 relatively long with stout and rather long ventrolateral seta, two relatively long, thin dorsodistal setae and two short and curved distal setae; P-5 with a single solenidion, four thin setae and three spines: proximal spine pointed, both distal spines with rounded tips.

Tibia of legs II, genu and tibia of legs III and IV with swimming setae; IV– Leg-4 ( Fig. 31 ) very long with distal projection, distal end of this projection blunt extending well beyond the insertion of IV–Leg-5 and bearing six rather long setae; IV–Leg-4 considerably longer than IV–Leg-5 + IV–Leg-6; IV–Leg claws with two subequal pointed denticles, claw lamella moderately developed with convex ventral margin ( Fig. 32 ).

Measurements, n=2. L of idiosoma (except petiole) 1150–1175, W 810–825; L of dorsal shield 875–885, W 510–525, distance between setae Oi–Oi 110–125, distance between setae Hi–Hi 385–400, distance between setae Sci–Sci 385–400, distance between setae Li–Li 25–35; L of medial margin of coxal plate III 85 –100, L of medial margin of coxal plate IV 160–175; L of petiole 225–235, W 123–125; W between the outer margins of pygal lobes 685–710; distance between medial margins of coxal plates IV 12–25; L of basal segment of chelicerae 125–135, L of cheliceral stylet 85–100; L of capitular bay 135–140; L of pedipalpal segments (P-1–5): 36–38, 75–80, 55–63, 100–112, 38–45; L of leg segments: I–Leg- 1–6—77 –85, 125–135, 150–160, 175–185, 16–175, 225–250; II–Leg- 1–6—75 –85, 135–150, 160–185, 210–225, 185–210, 210–275; III–Leg- 1–6—90 –100, 160–165, 160–170, 225– 235, 210–225, 260–275; IV–Leg-1–6—175–210, 250–265, 260–275, 460–475, 135–140, 185–210, L of distal projection of IV–Leg-4 85–90.

Female. Idiosoma wide (ratio L/ W 1.06 –1.07), narrowed anteriorly, widest near middle, with slightly concave anterior and convex posterior margins, posterolateral corners distinct ( Fig. 33 ). Dorsal and ventral shields present. Dorsal shield nearly circular (ratio length/width 0.97–1.06), bearing setae Oi and Hi anteriorly, Sci and Li posteriorly; dorsal furrow incomplete, obliterated caudally. Glandularia He lying on small humps, Le on posterolateral corners of the idiosoma.

Anterolateral corners of coxal plates I and II pointed, extending beyond the anterior idiosoma margin ( Fig. 34 ). Medial margin of coxal plates III shorter than medial margin of coxal plates IV, posterior coxal groups separated by a narrow interspace, lateral projection of coxal plates IV slightly extending beyond the lateral idiosoma margin. Gonopore relatively large (L 160-165), located slightly posterior to middle of the idiosoma; genital flaps with two large patches each, genital flap slightly wider than distance between posterior coxal groups; acetabular plates wide with three anteromedial and two-four posteromedial thin setae; glandularia Pe located between posteromedial margin of fourth coxae and genital plates; setae and glandularia Se on posterolateral corners; excretory pore open on small tubercle, and glandularia Ci on relatively large separate humps. Pedipalps as in male but femur with three dorsal setae and one ventrolateral seta.

Measurements, n=2. L of idiosoma 1275–1292, W 1200–1207; L of dorsal shield 825–901, W 840–850; distance between setae Oi–Oi 175–218, distance between setae Hi–Hi 508–550, distance between setae Sci–Sci 468– 550, distance between setae Li–Li 335–350; distance between medial margins of coxal plates IV 46 –50; L of genital flaps 158–165, W 80–86; L of genital plates 191–210, W 375–389; L of basal segment of chelicerae 125–150, L of cheliceral stylet 92–110; L of pedipalpal segments (P-1–5): 33–50, 86–93, 72–75, 124–125, 34–50; L of leg segments: I–Leg- 1–6—75 –90, 125–140, 165–200, 178–210, 167–170, 190–200; II–Leg- 1–6—92 –100, 135–152, 172–210, 210–260, 180–208, 200–218; III–Leg-1–6—105–110, 147–175, 178–190, 211–250, 204–215, 230–250; IV–Leg-1–6—165–200, 237–280, 244–250, 264–310, 224–250, 211–260.

Differential diagnosis. The new species is close to Arrenurus daubihensis Sokolow, 1931 , which is described on the base of the female only. The latter species are characterized by the following features: the dorsal shield is pentagonal, narrowed anteriorly, the dorsal furrow complete and the medial margin of the coxal plates III and IV is equal in length ( Sokolow 1931, 1940). In contrast, in the female A. neodaubihensis sp. n. the dorsal shield is circular and widely convex anteriorly, the dorsal furrow incomplete, the medial margin of the coxal plates III shorter than the medial margin of the coxal plates IV. The male of the new species is similar to the European species Arrenurus tricuspidator (Müller, 1776) . The male of A. neodaubihensis sp. n. differs from the male of A. tricuspidator by the following characters (characters states of the male A. tricuspidator are given in parentheses, data taken from Viets 1936, Cassagne-Méjean 1966): the hyaline membrane absent (present), the petiole has ventral appendix (absent), the petiole widest near middle (distally), the pygal lobes is long (short).

Etymology. The species named neodaubihensis , as has many features in common with A. daubihensis .

Habitat. Standing waters.

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

Figures

FIGURES 27 – 28. Arrenurus neodaubihensis sp. n., male: 27, idiosoma, dorsal view; 28, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 29 – 32. Arrenurus neodaubihensis sp. n., male: 29, chelicera; 30, pedipalp; 31, genu, tibia and tarsus of leg IV; 32, claw of leg IV. Scale bars = 100 µm for Fig. 31; 50 µm for Figs. 29, 30, 32.

FIGURES 33 – 34. Arrenurus neodaubihensis sp. n., female: 33, idiosoma, dorsal view; 34, idiosoma, ventral view. Scale bar = 100 µm.