Aturus insolitus, 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 : 20-24

Aturus insolitus sp. n.

( Figs. 55 –69)

Type series. Holotype: male (474-kas– IBSS), Russia, Primory Territory, Artemovsky Urban District, Steklyanukha River, N 43°21.027’; E 132°27.723’; depth 30 cm below the sediment surface; substrate: cobbles, pebbles, coarse- and medium-grained sand, 7.10.2010, leg. K.A. Semenchenko, D.A. Sidorov. Paratypes: 1 male (473-kas– IBSS), 3 females (475, 479-480-kas– IBSS), same data as holotype; 1 male (445-kas– IBSS), 1 female (447-kas– IBSS), with same locality as holotype, 12.06.2010, leg. K.A. Semenchenko, D.A. Sidorov; 1 male (428-kas– IBSS), Russia, Primory Territory, Partizansky District, Partizanskay River basin, Tigrovaya River, N 43o11.401’; E 133o12.660’; depth 30 cm below the sediment surface; substrate: cobbles, pebbles, sand, 12.06.2010, leg. K.A. Semenchenko, D.A. Sidorov.

Description. Male. Idiosoma oval, expanded in frontal part. Frontal margin with well developed triangular protrusion ( Fig. 55 ). Dorsal and ventral shields present, both with porous surfaces. Dorsal shield with lower and weakly striated part posterior to setae Si (striation visible on Figs. 62–63 ). Dorsum bearing caudo-dorsal projection with porteriorly some short and some more elongated setae. Setae Fp, Oi, Se and Pi without glandularia, other idiosomal setae associated with glandularia. Setae Fch and Oe longer than proterosomal setae Fp, Vi, Ve and Oi. First pair of lyriform organs (i1) situated anterior to setae Vi. Dorsal shield separated from ventral shield, with 6 pairs of setae: Oi, Hi, Si, Se, Ci and Pi; setae Hi thick and bifurcated other setae thin and simple. Setae Oe, He, Sci and Li situated on soft interscutal membrane, setae He bifurcated other setae simple. Second pair of lyriform organs (i2) situated posterior to sclerites bearing setae Oe, i3 posterior to Sci, i4 on sclerites bearing setae Li, i5 on dorsal shield laterally to setae Pi. All 4 pairs of genital acetabula visible from dorsal view. Excretory pore opens caudally on dorsal shield. Posterolateral surface of dorsum with numerous short thin setae, forming mainly 1 row and located more caudally long setae. Seta nearest to caudo-dorsal projection trifurcated ( Fig. 63 ).

Ventral shield ( Fig. 56 ) with deep median cleft and 4 genital acetabula on each side. Setae Pe and Le situated near posterolateral margins of venter. Median cleft with 2 thin setae on each side.

Capitulum slightly elongated with short anchoral process. Trochanter of pedipalp ( Fig. 57 ) short, thin with 1 dorsodistal seta. Ventral margin of femur convex. Femur with 3 dorsoproximal setae and 2 dorsodistal ones. Genu with 1 long and 1 short dorsodistal setae, its ventral margin concave. Tibia expanded distally with 2 ventrodistal setae (one thick and one thin), few thin dorsodistal and short distolateral spine.

Tibia of leg III with 13–14 long setae, 5 of which feathered ( Fig. 58 ). Trochanter of leg IV ( Fig. 59 ) with single short proximal spine and 2 dorsodistal ones; basifemur IV slightly curved; genu IV slightly expanded distally, with 2 ventrodistal setae exceeding length of tibia (one sword-like and one modified with 2 hooks on its tip) ( Figs. 64, 66–67 ), 7 long thin setae and some short, proximal short seta serrated ( Fig. 65 ); tibia ( Fig. 60 ) with 12 thin ventral setae of different length (4 proximal feathered longest, 2 distal feathered smallest), 1 drop-shaped pointed seta ( Fig. 64, 66 ), some thin and 1 stout serrated dorsal setae; tarsus shorter than tibia, expanded distally with slightly convex dorsal margin. Claws ( Fig. 61 ) asymmetrical: one claw with very long central denticle and short external and internal denticles (all three denticles with acute tips), other claw with wide rounded external and acute internal denticles, internal denticle slightly shorter than external.

68–69. Aturus insolitus sp. n., female: 68, idiosoma, dorsal view; 69, idiosoma, ventral view. Scale bar = 50 µm.

Measurements (n=3). Length of idiosoma 316–363, width 230–233; length of dorsal shield 262–277, width 187–191; length of capitulum 89–92, width 54–62; length of basal segment of chelicera 64–68, length of cheliceral stylet 18–20; length of capitular bay 68–69; length of pedipalpal segments (P-1–5): 21–22, 56–59, 32–35, 59–62, 27–28; length of leg segments: I-L- 1–6—32 –35, 51–53, 43–48, 56–62, 73–75, 81–83; II-L- 1–6—27–32, 51–54, 40–43, 54–62, 73–78, 86–89; III-L- 1–6—30–35, 54–56, 46–48, 70–73, 105–109, 89–94; IV-L- 1–6—62 –65, 100– 105, 86–88, 110–120, 108–110, 73–75.

Female. Idiosoma flat. Dorsal shield covering nearly all dorsal surface. Frontal margin with well developed rounded protrusion (Fig. 68). Setae Fp, Oi, Se and Pi without glandularia, other idiosomal setae associated with glandularia. Setae Fch and Oe longer and thicker than proterosomal setae Fp, Vi, Ve and Oi. First pair of lyriform organs (i1) situated anterior to setae Vi. Dorsal shield porous, with 1 piece of muscle attachment between setae Hi and Si on each side of idiosoma and small indentation in caudal part, bearing 4 pairs of setae: Oi, Hi, Si, Se; setae Hi thick and bifurcated other setae thin and simple. Setae Oe, He, Sci, Li and Ci situated on smooth interscutal membrane. Second pair of lyriform organs (i2) situated posterior to sclerites bearing setae Oe, i3 posterior to sclerites bearing setae Sci, i4 posterior to Li, i5 on ventral surface laterally to setae Pi.

Excretory pore opens posterior to dorsal shield on sclerite between setae Ci. Coxal shield (Fig. 69) occupying about 4/5 of ventral surface. Setae Sce and Pe situated on posterior margin of coxal shield. Anterior genital sclerite developed. Genital field with 4 pairs of acetabula, forming 1 row on plates along posterior margin of each side, each genital plate bearing 2 median and 1 distal thin setae. Pedipalps similar to those of male.

Measurements (n=3). Length of idiosoma 310–317, width 244–254; length of dorsal shield 273–277, width 210–212; length of capitulum 89–90, width 56–67; length of basal segment of chelicera 67–72, length of cheliceral stylet 22–24; length of capitular bay 63–68; length of pedipalpal segments (P-1–5): 18–20, 56–57, 32–33, 59–62, 31–32; length of leg segments: I-L- 1–6—36 –38, 48–51, 40–42, 50–51, 66–68, 70–74; II-L- 1–6—40 –42, 48–49, 40–42, 50–54, 65–73, 75–77; III-L- 1–6—40 –43, 51–53, 40–43, 57–59, 84–85, 81–84; IV-L- 1–6—62 –65, 81–86, 67–70, 95–100, 100–105, 86–89.

Differential diagnosis. The males of new species are similar to A. estellae Habeeb, 1953 in the shape of the idiosoma, the posterolateral surface of the dorsum with 1 row of short, thin setae and the characteristic shape of caudo-dorsal projection, the last feature exists only in these two species from the genus Aturus . The new species differs in the following characters (character states of A. estellae are given in parentheses, data taken from Habeeb 1953 and Mitchell 1954): He bifurcated (simple), posterior margins of the genital cleft not fused (fused to each other), row of 4 genital acetabula on each side of posterior idiosoma margin (genital acetabula shifted—4–6 on each side of the posterior projection, 18–25 on the ventral and lateral surface of the posterior projection), tibia of leg III with 13–14 long setae, 5 of which feathered (leg III unmodified). Females of A. insolitus sp. n. have bifurcated setae Hi on the dorsal shield, whereas in other females of the genus Aturus these setae are simple. Males of A. insolitus sp. n. have some features in common with males of Aturus kumariensis Kim & Chung, 1993 but differ in the following characters (character states of A. kumariensis are given in parentheses from Kim & Chung 1993): frontal margin with triangular protrusion (straight), caudo-dorsal projection that overtop of other part of dorsal surface present (absent), 4 pairs of genital acetabula (6 pairs), genu of leg IV with 2 ventrodistal setae exceeding length of tibia (one sword-like and one modified with 2 hooks on its tip) (with 2 stout ventrodistal setae rounded on tips, one of which exceeding length of tibia).

Etymology. The species epithet insolitus is Latin for "strange", implying possession of unusual structure in the present species—caudo-dorsal projection.

Habitat. Interstitial waters.

Distribution. Russia: Far East, Primory Territory.

Figures

FIGURES 55 – 61. Aturus insolitus sp. n., male: 55, idiosoma, dorsal view; 56, idiosoma, ventral view; 57, pedipalp, lateral view; 58, genu, tibia and tarsus of leg III; 59, trochanter, basifemur, telofemur and genu of leg IV; 60, tibia and tarsus of leg IV; 61, claws of leg IV. Scale bars = 50 µm for Figs. 55 – 56; 59 – 60; 25 µm for Figs. 57 – 58, 61.

FIGURES 62 – 67. Aturus insolitus sp. n., male: 62, idiosoma, dorsolateral view; 63, idiosoma, dorsolateral view (posterior part); 64, genu and tibia of leg IV; 65, proximal short serrated seta on genu of leg IV; 66, tips of modified seta with two hooks on genu of leg IV and drop-shaped pointed seta on tibia of leg IV; 67, tip of modified seta with two hooks on genu of leg IV. SEM.