A New Record of the Water Mite Hydryphantes Tenuipalpis Thon (Acariformes, Hydryphnatidae) for Russia, with Description of Its Developmental Stages P.V
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Acarina 16 (1): 57–64 © ACARINA 2008 A NEW RECORD OF THE WATER MITE HYDRYPHANTES TENUIPALPIS THON (ACARIFORMES, HYDRYPHNATIDAE) FOR RUSSIA, WITH DESCRIPTION OF ITS DEVELOPMENTAL STAGES P.V. Tuzovsky Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Yaroslavl Prov., 152742 Russia ABSTRACT: The first illustrated description of the larva, deutonymph and adults of the water mite Hydryphantes tenuipalpis from Yaroslavl Province, Russia is given. KEY WORDS: Hydryphantidae, Hydryphantes tenuipalpis, water mite, larva, deutonymph, female, male. INTRODUCTION The water mite Hydryphantes tenuipalpis is small platelets with setae Fch and Fp. Posterior widely distributed in Europe and is only known plate narrows anteriorly and widens posteriorly; from adults (Lundblad 1968; Gerecke 1996). I setae Vi and Oi situated on posterior portion of found this species for the first time in Russia (Yaro- plate. Medial eye weakly developed, situated be- slavl’ Province) and describe the larva, deutonymph tween setae Vi. Both pairs of trichobothria thin, Fp adults. long, Oi short. Distance between bases of trichoboth- MATERIAL AND METHODS ria Oi shorter than their length. Simple proterosom- al setae (Fch, Vi and Oe) thick, but Fch slightly Six deutonymphs, 9 females, and 3 males were shorter than Vi and Oe. Hysterosomal dorsal setae collected by the author from woodland temporary Hi, He, Sci, Sce, Li, and Le subequal, their bases ponds near Borok, Nekouz Distr., Yaroslavl’ Prov- situated on very small rounded sclerites. ince, May–July 2000. Larvae (n=14) reared from Coxae II triangular, coxae I and III trapezoid three females in the laboratory conditions. The and broadly rounded medially (Fig. 1, b). Lateral duration of the embryonic period at room temper- setae on coxae I shorter than medial setae on coxae ature was 12–17 days. I and III. Urstigma rather large and situated on The nomenclature of the idiosomal setae and anterior edge of coxa II near its middle. Setae Si lyriform organs follows Tuzovsky (1987). The longer and thicker than other hysterosomal ventral following abbreviations are used: s — solenidion, setae. Setae Ci, Se, Pi and Pe subequal and slightly s1— solenidion on tarsus of legs I, s2 — solenidion longer than anal setae (Ai, Ae). on tarsus of legs II; e — eupathidium, ac — acan- Anal plate small, its shape variable (Fig. 2, a– thoid seta; P1–5, pedipalpal segments (trochanter, d). Anal opening posterior to setae Ai in posterior femur, genu, tibia and tarsus); I Leg.1–6, first leg, portion of the plate. Setae Ai and Ae subequal. segment 1–6 (trochanter, basifemur, telofemur, Capitulum (Fig. 2, e) with wide base and genu, tibia and tarsus); tarsus of leg I: de1— dis- comparatively narrow rostrum, ventral setae longer tance between the anterior end of the segment and than dorsal ones. The mouth opening surrounded eupathidium, ds1 — distance between the anterior by numerous papillae. Basal part of capitulum with end of the segment and solenidion; tarsus of leg II: distinct, scale-like patterns. Basal segment of che- de2 — distance between anterior end of the segment licera striate (Fig. 2, f). Cheliceral stylet heavy and and eupathidium, ds2 —distance between the ante- without apical teeth (Fig. 2, g). rior end of the segment and solenidion; n — the Palps moderately long (Fig. 2, h). Trochanter number of measured specimens. Measurements are short without setae, femur with single dorsal seta. given in micrometers. Genu with thick proximal seta and thin distal one. Hydryphantes tenuipalpis Thon, 1899 Tibia with three subequal, thin setae and large bifurcated dorsodistal claw. Tarsus with long sole- Figs 1–7. nidion, two short, thin proximal setae, and five Larva. Color red. Body oval, dorsal shield is thick, long setae. divided into 3 parts (Fig. 1, a). Proterosoma with 5 Leg 6-segmented. Leg II distinctly shorter pairs of setae: Fch, Fp, Vi, Oi, Oe. Anterior pair of than anterior and posterior ones. Number of leg P.V. Tuzovsky a b Fig. 1. Hydryphantes tenuipalpis, larva: a— dorsal view, b — ventral view. h ab cd f g e Fig. 2. Hydryphantes tenuipalpis, larva: a–d — anal plate, e — capitulum, ventral view; f — chelicera, dorsal view; g — cheliceral stylet, lateral view; h — pedipalp, lateral view. setae (specialized setae indicated in parentheses): I setae heavy and usually with long serrations. Leg. 1–6 — 1, 2, 5, 6 (s, e), 13 (2s, e), 23 (s, e, ac); Eupathidia situated in distal parts of genu I and tibia II Leg. 1–6 — 1, 2, 5, 6 (s, e), 12 (2s), 22 (s, e, ac); I (Fig. 3, a), and occupy proximal position of tarsus III Leg. 1–6 — 1, 1, 5, 5 (s), 11 (s), 20. All simple I, close to solenidion basis. Solenidion and eupathid- 58 A new record of the water mite Hydryphantes tenuipalpis a d b e c Fig. 3. Hydryphantes tenuipalpis, larva: a — genu, tibia and tarsus of leg I, b — genu, tibia and tarsus of leg II, c — genu, tibia and tarsus of leg III, d — claws of leg I, e — claws of leg III. Simple setae on genu, tibia and tarsus I–IV are not shown. ium on genu I subequal. Solenidion 2.5–3.0 times 13–15, 21–27, 33–40, 57–67; III Leg. 1–6 — 27– longer than eupathidium on genu II (Fig. 3, b). Tibia 30, 20–22, 15–18, 23–28, 40–44, 61–72; ds1 11–13, I and II with unequal proximal solenidia. Genua I– de1 6–8, ds2 6–9, de2 32–34. III with proximal solenidia (Fig. 3, a–c). Solenidia Deutonymph. Color red. Body oval and some- on genu and tibia III subequal. On tarsus II, solenid- what flattened dorsoventrally. Dorsal plate relative- ion is proximal and eupathidium is submedial. ly small, distinctly narrows laterally, anterior margin Tarsi I and II with rather long distal acanthoid setae. convex, posterior margin straight or slightly concave Empodium large and crescent on all tarsi. (Fig. 4, a). Posterolateral projections of dorsal plate Ambulacra short and thin on tarsi I and II (Fig. 3, d), short, their length equal to 1/5 length of basal portion they are slightly shorter than on tarsi III (Fig. 3, e). of plate. Proterosoma with six pairs of setae (Fch, Fp, Measurements (n=5). Length of the dorsal Vi, Ve, Oi, Oe). Dorsal plate has two pair of tri- plate 37–44, width 45–50; length of urstigma 11– chobothria (Fp, Oi) and medial eye, situated posteri- 13, height 6–8; diameter of anterior lateral eyes 15– or bases of Fp. Base of trichobothria Oi anterior to 17; length of anal plate 10–13, width 10–14; length posterior margin of plate. Setae Fch longer and of setae Fch 28–30; length of setae Fp 65–72; thicker than other idiosomal setae. Trichobothria Fp length of setae Vi 36–47; length of setae Oi 14–25; and Oi without glandularia, other dorsal setae with distance between bases of setae Vi 41–44; distance accompanying glandularia. Lateral eyes in capsules. between bases of setae Oi 15–25; length of capitu- First pair of lyriform organs (i1) slightly posterior to lum 100–112, width 90–100; length of rostrum 55– eye capsules; i2–i4 similarly situated, anterior to 60; length of basal segment of chelicera 85–92, humeral, scapular, and lumbar rows of setae. width 35–38; width of strips on basal segment of Leg coxae (Fig. 4, b) in engorged/fully devel- chelicera 0.5–1.0, distance between strips on basal oped specimens occupy approximately one-half segment of chelicera 0.3–0.8; length of cheliceral length of body. All coxae with long, thin setae. stylet 22–25; length of the palpal segments (P 1–5): Medial edge of coxae III well developed, two times 6–8, 31–38, 31–35, 18–20, 11–14; length of legs shorter than lateral one. Coxae IV triangular, their segments: I Leg. 1–6 — 26–34, 20–24, 18–22, 31– medial edges weakly developed. Lateral edge of 38, 38–42, 75–82; II Leg. 1–6 — 25–28, 20–25, coxae IV longer than lateral edge of coxae III. Anal 59 P.V. Tuzovsky a b c Fig. 4. Hydryphantes tenuipalpis, deutonymph: a — dorsal view, b — ventral view, c — fragment of integument. opening surrounded by sclerotized ring. Setae Pi two, setae. Pedipalpal tibia tapering distally, with 2 without glandularia; other ventral idiosomal seta lateral (internal and external) setae, one thin dorsal (Ci, Se, Pe, Hv) with accompanying glandularia. seta, and short thick spine. All setae of tibia distal. Fifth pair of lyriform organs (i5) lateral and slightly Pedipalpal tarsus (Fig. 5, f) with short proximal posterior to setae Ci. Integument with numerous solenidion and 8 simple (thin and thick) setae rounded papillae (Fig. 4, c). situated mainly in distal portion of segment. External genital organ with two pair of acetab- Swimming setae present on following segments ula, genital sclerite rather large, pre- and postgen- of legs (Leg Telofemur Genu Tibia): II — 0 , 0–2, 8– ital sclerites small. Anterior and posterior genital 12; III — 2–3, 4–7, 7–10; IV — 2–3, 9–11, 8–13. acetabula (Fig. 5, a–b) almost equal in size and Claws simple, without additional denticles, shape. Genital flaps wide, with 5–7 thin setae, but with dorsal plate. situated along their medial margins. Measurements (n=6). Length of body 935– Capitulum (Fig. 5, c) with short rostrum, length 1190, width 875–1100; length of dorsal plate 210– equals to 1/9–1/10 length of capitulum. Ventral 350, width 210–350, length of posterior projections edge of capitular base convex. Mouth disc rather of dorsal plate 37–62; length of genital flaps 75–88, large, with numerous short papillae, dorsal and width 62–75; diameter of genital acetabula (ac.1– ventral pairs of setae subequal.