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© Амурский зоологический журнал V(1), 2013.13-15
Accepted: 28.01.2013
УДК 595.426
© Amurian zoological journal V(1), 2013.13-15
Published: 29.03.2013
DEUTONYMPHAL MORPHOLOGY OF THE WATER MITE SPERCHON CRASSIPALPIS MARSHALL
(ACARI: HYDRACHNIDIA, SPERCHONTIDAE)
P.V. Tuzovskij
[Тузовский П.В. Дейтонимфальная морфология водяного клеща Sperchon crassipalpis Marshall (Acari, Hydrachnidia: Pionidae)]
Institute for Biology of Inland Waters Russian Academy of Sciences, 152742, Borok, Nekouzskii District, Yaroslavl Province, Russia. E-mail: tuz@ibiw.yaroslavl.ru
Институт биологии внутренних вод РАН, 152742, Борок, Некоузский район, Ярославская область, Россия. E-mail: tuz@ibiw.yaroslavl.ru
Key words: Hydrachnidia, Sperchontidae, Sperchon, Palpisperchon, water mites, morphology, deutonymph Ключевые слова: Hydrachnidia, Sperchontidae, Sperchon, Palpisperchon, водяные клещи, морфология, дейтонимфа
Summary. The study presents a detailed description of the deutonymph of water mite Sperchon crassipalpis Marshall, 1933. Резюме. Детальное описание дейтонимфы водяного клеща Sperchon crassipalpis Marshall, 1933.
INTRODUCTION
The water mite Sperchon crassipalpis Marshall, 1933 is only known from adults [Marshall, 1933; Cook 1974; Wainstein, 1976]. The purpose of the present paper is to describe its deutonymph.
MATERIAL AND METHODS
The examined material (three deutonymph) was collected by T.S. Vshivkova in the Komarovka River
of the Primorskii Krai of Russia, 08.07.1984. Specimens were fixed by 3% formaldehyde solution and mounted on slides using Hoyer's medium.
Idiosomal setae and lyriform organs are named according to Tuzovskij [1987]: Fch - frontales cheli-cerarum, Fp - frontales pedipalporum, Vi - verticales internae, Ve - verticales externae, Oi - occipitales internae, Oe - occipitales externae, Hi - humerales internae, He - humerales externae, Hv - humerales
ventralia, Sci - scapulares internae, Sce - scapulares externae, Li - lumbales internae, Le - lumbales ex-ternae, Si - sacrales internae, Se - sacrales externae, Ci - caudales internae, Pi - praeanales internae, Pe - praeanales externae; i1 - i5 - lyriform or slit organs.
The following abbreviations are used: P-1-5, pedipalp segments (trochanter, femur, genu, tibia and tarsus); I-Leg-1-6, first leg, segments 1-6 (trochanter, basifemur, telofemur, genu, tibia and tarsus) i.e. III-Leg-4 = genu of third leg; ac. 1-2, genital acetab-ula (anterior, posterior); n = number of specimens measured. The length of appendage segments was measured along their dorsal side; all measurements are given in ^m.
SYSTEMATIC PART
Family Sperchontidae Thor, 1900 Genus Sperchon Kramer, 1877 Sperchon (Palpisperchon) crassipalpis Marshall, 1933 (Figs. 1-8)
Diagnosis. Deutonymph. Integument with small papillae, both pairs of genital acetabula large oval and situated closely together.
Deutonymph, description. Body flat and oval. Integument with small papillae. The number and position of idiosomal setae and lyriform organs typical for the genus Sperchon, but glandularia Pe absent (Figs 1-2). Trichobotria Fp, Oi, setae and Pi without glandularia, other dorsal setae associated with glan-dularia and located on relatively large tubercles or warts. Sclerites bearing trichobothria Oi much larger than sclerites bearing trichobothria Fp. Setae Fch, Fp, Vi, Oi, Ve, median eye, eye capsules and first pair of lyriform organs (i1) situated closely together at anterior end of idiosoma; setae He, Li and Si, four pairs of lyriform organs (i2-i4) situated along lateral edges of idiosoma. Eye capsules relatively large, median eye small.
Coxae of legs combined into four groups, occupying about half of ventral surface of idiosoma. Postero-medial portions of coxae of legs I-II close together, but not fused to each other, with slightly developed posteromedial apodemes. Anterior and posterior coxal groups well separated. Posterior coxal groups widely separated, their combined length greater than width on each side. Setae Hv located in lateral posi-
tion between coxae II and III; setae Sce situated behind posterior margin of coxae IV; setae Oe, Le and Se located along lateral margins of ventral surface. Excretory pore surrounded by sclerotized ring and located between setae Ci. Setae Pi and Ci arranged in longitudinal rows. External genital organ placed between coxae IV.
Genital acetabula (4) oval, relatively large and almost subequal, anterior and posterior pairs of acetabula situated close together (Fig. 3). Genital flaps separated narrow with well developed secondary scleroti-zation, each flap bearing three thin setae.
Capitulum (Fig. 4) with relatively large base and short rostrum. Chelicera (Fig. 5) with long basal segment and small stylet.
Pedipalp (Fig. 6) compact: P-1 very short, without setae; P-2 stocky, high with five unequal setae and large ventrodistal projection bearing one short seta; P-3 shorter than femur, with one dorsodistal and one ventrodistal seta; P-4 longer than genu, curved dor-soventrally, with two subequal peg-like ventral setae and three thin dorsal setae; proximal peg-like seta situated near middle of the segment, distal peg-like seta in its distal portion.
Legs without swimming setae, with a few thick and thin short setae (Fig. 7). Tarsi of all legs slightly thickened distally. Claws with well developed blade (its ventral margin slightly concave) and two clawlets of unequal length, external clawlet longer than internal clawlet (Fig. 8).
Measurements (n=3). Length of body 675-785, width 560-645; length of coxae I-II 140-150, width 120-130; length of coxae III-IV 160-170, width 130-140; length of genital flaps 72-78, width 15-18, length/width of genital acetabula (ac.1-2): 24-30/2024; 25-31/20-24; length of pedipalpal segments (P-1-5): 17-19, 78-85, 50-54, 65-70, 25-30; length of leg segments: I-Leg-1-6: 60-65, 60-70, 90-100, 105-110, 105-115; II-Leg-1-6: 45-48, 60-65, 6072, 105-115, 115-135, 115-135; III-Leg-1-6: 5055, 60-65, 110-125, 125-145, 125-145; IV-Leg-1-6: 65-90,75-95, 80-90, 150-170, 135-165.
Remarks. The water mite S. crassipalpis has been repoted from Northern America [Marshall, 1933; Cook, 1974] and Kamchatka [Wainstein, 1976]. Adults of this species has been found by me in materials from the Chayandra River (Irkutsk Province, Asian part of Russia) and from the Pechora River basin (European part of Russia), leg. O.S. Tsember.
The world fauna of water mites of the subgenus Palpisperchon Lundblad, 1941 currently includes five species: S. crassipalpis, S. mirabilis Lundblad, 1941, S. distans Scheffler, 1972; S. nikkoensis Imamura, 1976 and S. skopetsi Tuzovskij, 1982, 1990. All species of this subgenus are described on adults and only
in S. distans and S. skopetsi deutonymphs are known [Scheffler, 1972 and Tuzovskij, 1990 respectively]. In the fauna of Russia the following species of this subgenus are recorded: S. crassipalpis, S. distans and S. skopetsi. Distinctions between deutonymphs of these species are given in a key.
Key to deutonymphs of the Russian species of the subgenus Palpisperchon
1 (2) Integument with small papillae..........................
S. (Palpisperchon) crassipalpis Marshall, 1933
2 (1) Integument fine lined or with strips and ribs
3 (4) Integument fine lined, genital acetabula square
(Scheffler, 1972)............................................
........S. (Palpisperchon) distans Scheffler, 1972
4 (3) Integument with strips and ribs, genital acetabu-
la circular (Tuzovskij, 1990)...........................
.....S. (Palpisperchon) skopetsi Tuzovskij, 1982
ACKNOWLEDGEMENTS
I express sincere gratitude to anonymous referees for reviewing the manuscript. I also grateful T.S. Vshiv-kova and O.S. Tsember for collecting the material.
REFERENCES
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