Aturus sikhotealinensis, Semenchenko, Ksenia A. & Tuzovskij, Petr V., 2011

Semenchenko, Ksenia A. & Tuzovskij, Petr V., 2011, New water mites species of the genus Aturus Kramer (Acariformes, Aturidae) from the Far East of Russia, Zootaxa 2933, pp. 1-26 : 7-9

Aturus sikhotealinensis sp. n.

( Figs. 14–19 )

Type series. Holotype: male (199-kas– IBSS), Russia, Primory Territory, Terneysky District, “Sikhote-Alin State Nature Biosphere Reserve”, Sea of Japan basin, spring Stradny; depth 7 cm; substrate: pebbles, medium-grained sand. 17.10.1991, leg. E.V. Potikha. Paratype: 1 male (198-kas– IBSS), same data as holotype.

Description. Male. Idiosoma oval, expanded in caudal part. Frontal margin convex, with small median incision ( Fig. 14 ). Dorsal and ventral shields present, both with porous surfaces. Setae Fp, Oi and Pi without glandularia, other idiosomal setae associated with glandularia. Setae Fch, Fp and Oe longer than proterosomal setae Vi, Ve and Oi. Setae Vi and first pair of lyriform organs (i1) situated on small platelets. Dorsal shield separated from ventral shield, with 6 pairs of simple setae: Oi, Hi, Si, Se, Ci and Pi; setae Hi long, thick other setae short, thin. Setae Oe, He, Sci and Li situated on soft interscutal membrane. Second pair of lyriform organs (i2) situated posterior to sclerites bearing setae Oe, i3 on sclerites bearing setae Sci, i4 posterior to Li, i5 on dorsal shield laterally to setae Pi. One pair of genital acetabula located dorsally posterior to setae Sce on each side of idiosoma. Excretory pore opens caudally on dorsal shield. Posterolateral surface of dorsum with numerous thin setae, forming mainly 1 row.

Ventral shield ( Fig. 15 ) with deep median cleft and 4–6 genital acetabula on each side. Setae Pe and Le situated near posterolateral margins of venter. Median cleft with 4–5 thin setae on each side.

Capitulum slightly elongated with short anchoral process. Trochanter of pedipalp ( Fig. 16 ) short, thin with 1 dorsodistal seta. Ventral margin of femur convex. Femur with 3 dorsoproximal setae and 2 dorsodistal ones. Genu with 2 long dorsodistal setae, its ventral margin concave. Tibia expanded distally with 2 ventrodistal setae (one thick and one thin), 1 thin dorsodistal and short distolateral spine.

Tibia of leg III with 24–25 long setae ( Fig. 17 ). Trochanter of leg IV ( Fig. 18 ) with single short proximal spine and 2 dorsodistal ones; basifemur IV curved; genu IV slightly expanded distally, with 2 ventrodistal sword-like setae exceeding length of tibia, 7 thin ventral setae of different length, 3 dorsal setae, more distal setae feathered; ventral surface of tibia IV with 7 setae of subequal in length (3 proximal setae feathered), 4 longer thin setae and 2 short, thick setae; its dorsal surface with 4 short setae, more distal seta feathered; tarsus shorter than tibia, expanded distally with slightly convex dorsal margin. Claws ( Fig. 19 ) asymmetrical: one claw with very long central acute denticle, short external acute and internal slightly rounded denticles, other claw with long wide rounded external and short acute internal denticles.

Measurements (n=2). Length of idiosoma 469–482, width 310–312; length of dorsal shield 376–389, width 270–277; length of capitulum 86–94, width 67–73; length of basal segment of chelicera 75–86, length of cheliceral stylet 27–29; length of capitular bay 92–97; length of pedipalpal segments (P-1–5): 24–27, 54–57, 32–38, 73–76, 28–30; length of leg segments: I-L- 1–6—48 –49, 65–67, 57–58, 78–80, 86–95, 103–105; II-L- 1–6—51 –52, 70–73, 62–63, 89–92, 100–105, 113–114; III-L- 1–6—57 –58, 78–79, 75–78, 127–128, 143–146, 137–140; IV-L- 1–6—81 – 84, 154–159, 127–130, 154–159, 124–126, 110–113.

Differential diagnosis. The new species is similar to A. barbatulus Viets, 1936 (Western Palaearctic) and A. karamani Viets, 1936 (Europe) . Males of these species have 2 or many rows on the posterolateral margin of the dorsum and a developed ventrodistal projection on the pedipalpal femur ( Viets 1936; Motaş & Angelier 1967). In contrast, A. sikhotealinensis sp. n. has the posterolateral surface of the dorsum with numerous setae, forming mainly 1 row and without ventrodistal projection on the pedipalpal femur. The acetabula of A. sikhotealinensis sp. n. are situated in 1 row on the posterolateral margin of the ventral shield (in A. barbatulus 1 or 2 acetabula at both sides of median cleft, situated anteriorly to the row of other acetabula), genu of leg IV with 2 ventrodistal swordlike setae exceeding length of tibia and 1 feathered setae (genu of leg IV in A. barbatulus and A. karamani with more stout sword-like setae, much shorter than length of tibia, bearing 5 feathered setae in A. barbatulus and no feathered setae in A. karamani ).

Etymology. The species is named after the Sikhote-Alin mountain range in Primory and Khabarovsk Territories, Russia.

Habitat. Running waters.

Distribution. Russia: Far East, Primory Territory.

Figures

FIGURES 14 – 15. Aturus sikhotealinensis sp. n., male: 14, idiosoma, dorsal view; 15, idiosoma, ventral view. Scale bar = 50 µm.

FIGURES 16 – 19. Aturus sikhotealinensis sp. n., male: 16, pedipalp, lateral view; 17, genu, tibia and tarsus of leg III; 18, leg IV; 19, claws of leg IV. Scale bars = 50 µm for Figs. 17 – 18; 25 µm for Figs. 16, 19.