Aturus pulcher, 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 : 15-19

Aturus pulcher sp. n.

( Figs. 36–54 )

Type series. Holotype: male (461-kas– IBSS), Russia, Primory Territory, Khasansky District, “Kedrovaya Pad National Nature Biosphere Reserve”, Sea of Japan basin, Goraysky spring, flowing into the Kedrovaya River, N 43°06.015’; E 131°33.398’; depth 10–20 cm; substrate: boulders, cobbles, pebbles, fine-grained sand. 3.10.2010, leg. K.A. Semenchenko, D.A. Sidorov. Paratypes: 2 males (462-463-kas– IBSS), 1 female (460-kas– IBSS), 2 deutonymphs (467-468-kas– IBSS), same data as holotype; 2 males (73-74-kas– IBSS), 1 female (75-kas– IBSS), with same locality as holotype, 13.09.2006, leg. K.A. Semenchenko, D.A. Sidorov.

Description. Male. Idiosoma almost rounded. Frontal margin convex, with small median incision ( Fig. 36 ). Setae Fp, Oi 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. Setae Vi and first pair of lyriform organs (i1) situated on platelets. Dorsal surface with net structure. Dorsal shield separated from ventral shield, with depressions in frontal part, posterior to setae Si and Se, and along excretory pore ( Fig. 43–44 ); 1 piece of muscle attachment scar near to frontal depression on each side of idiosoma, another piece laterally to setae Pi, 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 Oe and He bifurcated, Oe slightly longer than He. 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 posterior to setae Pi. Excretory pore opens caudally on dorsal shield. Posterolateral surface of dorsum ( Fig. 44 ) with numerous short, thin, feathered setae in front, and numerous long thick and thin smooth setae located more distally, 3–6 pairs of spatulate modified setae caudally.

Ventral shield ( Fig. 37 , 45–46 ) with deep median cleft and 9–10 genital acetabula on each side. Some long setae located posterolaterally. 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. 38 ) short, thin with 1 dorsodistal seta. Ventral margin of femur straight, with developed ventrodistal projection. Femur with 3 dorsoproximal setae and 3 dorsodistal ones. Genu with 2 dorsodistal setae, its ventral margin slightly concave. Tibia expanded distally with 2 ventrodistal setae (one thick and one thin), few thin dorsodistal ones and short distolateral spine.

Tibia of leg III with 45–53 setae, 4 ventral of which with 2–5 branches ( Fig. 39 ). Trochanter of leg IV ( Fig. 40 ) with single short proximal setae and 2 dorsodistal ones; basifemur IV curved; genu IV expanded distally, with 2 ventrodistal long sword-like setae, 8 ventral setae: 6 bifurcated at the tips, 1 proximal feathered short and 1 distal simple long setae, some dorsodistal setae of different length; tibia IV ( Fig. 41 , 47–48 ) with 7 serrated (5 proximal and 2 distal), 9 ventral smooth setae, 2 distal of which longer and thicker and some distal setae of different length (1 seta feathered); tarsus and tibia approximately subequal, tarsus expanded distally with slightly convex dorsal margin. Claws ( Fig. 42 ) asymmetrical: one claw with very long central denticle and short external and internal denticles (all three denticles with acute tips), other claw with short acute external, long wide rounded central and acute internal denticles.

Measurements (n=3). Length of idiosoma 483–495, width 435–442; length of dorsal shield 396–442, width 363–376; length of capitulum 122–124, width 67–74; length of basal segment of chelicera 97–118, length of cheliceral stylet 29–31; length of capitular bay 118–120; length of pedipalpal segments (P-1–5): 32–33, 70–72, 54–56, 105–107, 38–39; length of leg segments: I-L- 1–6—54 –59, 78–81, 73–76, 100–102, 124–127, 121–123; II-L- 1–6 – 54 –65, 92–95, 84–85, 117–119, 140–143, 132–135; III-L- 1–6—67 –76, 116–118, 117–121, 167–171, 210–221, 156–162; IV-L- 1–6—97 –100, 175–178, 125–130, 151–159, 210–216, 202–204.

Female. Idiosoma flat. Dorsal shield covering nearly all dorsal surface. Frontal margin convex, with small median incision ( Fig. 49 ). Setae Fp, Oi 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 scar posterior to eyes on each side of idiosoma, bearing 4 pairs of setae: Oi, Hi, Si, Se, with small indentation in caudal part. Setae Oe, He, Sci, Le, 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 above setae Ci. Coxal shield ( Fig. 50 ) occupying about 4/5 of ventral surface. Setae Sce and Pe situated between posterior margin of coxal shield and genital plates. Anterior genital sclerite developed. Genital field with 8–10 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 484–581, width 449–554; length of dorsal shield 403–449, width 356–383; length of capitulum 118–121, width 79–81; length of basal segment of chelicera 110–113, length of cheliceral stylet 35–38; length of capitular bay 99–122; length of pedipalpal segments (P-1–5): 32–33, 62–68, 51–53, 97–100, 35–37; length of leg segments: I-L- 1–6—48 –59, 67–75, 56–62, 72–78, 92–95, 92–94; II-L- 1–6 –46 –56, 70–75, 59–62, 84–86, 100–106, 103–108; III-L- 1–6—54 –59, 76–84, 70–78, 102–104, 132–140, 113–122; IV-L- 1– 6—75 –81, 108–113, 92–98, 121–132, 146–151, 136–140.

Deutonymph. Idiosoma round, with 1 anterior large fungiform plate, 2 pairs of medium and 1 pair of small trapezoidal plates ( Fig. 51 ). All dorsal setae situated on smooth integument. Setae Fch longer and thicker than other idiosomal setae. First pair of lyriform organs (i1) and setae Vi situated on common sclerites, i2 anterior to Hi, i3 posterior to Sce, i4 posterior to Li, i5 on ventral side lateral to Ci. Dorsal plates with cell-shaped reticulation, smooth integument striated.

Coxal plates arranged into four groups ( Fig. 52 ). Anterior groups are close to each other, while posterior coxal groups well separated. Coxae I with short narrow apodemes. Setae Hv situated on coxae II posterolaterally. Suture line between coxae III–IV incomplete. Each genital plate with 2 acetabula and 4 thin setae. Pregenital sclerite small, situated between posterior margin coxae III–IV and genital plate. Excretory pore plate lying ventrally near posterior idiosoma margin.

Pedipalpal trochanter without seta ( Fig. 53 ), femur with slightly convex ventral margin, bearing 3 dorsodistal setae; genu with 2 dorsodistal setae; tibia with 2 ventrodistal setae (one thick and one thin), and short distolateral spine. Claws ( Fig. 54 ) with 3 clawlets: short external and longer central.

Measurements (n=3). Length of idiosoma 350–403, width 290–330; length of larger dorsal plate 108–112, width 129–132; length of capitulum 75–77, width 67–81; length of basal segment of chelicera 72–75, length of cheliceral stylet 29–30; length of capitular bay 72–86; length of pedipalpal segments (P-1–5): 22–23, 42–43, 30– 32, 60–65, 27–28; length of leg segments: I-L- 1–6—28–29, 33–35, 30–46, 43–59, 54–58, 50–59; II-L- 1–6 –28–38, 32–35, 30–48, 46–62, 56–65, 58–65; III-L- 1–6—27–29, 38–42, 32–35, 51–54, 70–73, 70–71; IV-L- 1–6—37 –46, 45–48, 43–46, 62–65, 75–78, 79–84.

Differential diagnosis. The new species is similar to Aturus mirabilis Piersig, 1896 , but differs in the following characters (character states of A. mirabilis are given in parentheses, data taken from Mitchell 1956): posterolateral margin of the dorsum with numerous short and long setae (dorsum without setae on posterolateral margin), genu of leg IV with 6 bifurcated at the tips and 1 feathered setae (all setae on this segment simple and smooth), tibia of leg IV with 7 serrated setae—5 proximal and 2 distal (with 5 proximal serrated setae). A. pulcher sp. n. has also some features in common with A. polysetus sp. n. (see above).

Etymology. The species epithet pulcher is Latin for "beautiful".

Habitat. Running waters.

Distribution. Russia: Far East, Primory Territory.

Figures

FIGURES 36 – 37. Aturus pulcher sp. n., male: 36, idiosoma, dorsal view; 37, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 38 – 42. Aturus pulcher sp. n., male: 38, pedipalp, lateral view; 39, genu, tibia and tarsus of leg III; 40, trochanter, basifemur, telofemur and genu of leg IV; 41, tibia and tarsus of leg IV; 42, claws of leg IV. Scale bars = 50 µm for Figs. 39 – 41; 25 µm for Figs. 38, 42.

FIGURES 43 – 48. Aturus pulcher sp. n., male: 43, idiosoma, dorsal view; 44, posterior part of dorsal shield; 45, idiosoma, ventral view; 46, posterior part of ventral shield; 47, leg IV (trochanter missing); 48, distal part of genu and tibia of leg IV (feathered setae scaled-up). SEM.

FIGURES 49 – 50. Aturus pulcher sp. n., female: 49, idiosoma, dorsal view; 50, idiosoma, ventral view. Scale bar = 100 µm.

FIGURES 51 – 54. Aturus pulcher sp. n., deutonymph: 51, idiosoma, dorsal view; 52, idiosoma, ventral view; 53, pedipalp, lateral view; 54, claw of leg IV. Scale bars = 50 µm for Figs. 51 – 52; 25 µm for Figs. 53 – 54.