Aturus indicus

Pesic, Vladimir & Panesar, Arne, 2009, Studies on water mites (Acari, Hydrachnidia) from the Himalayas, II. New records and descriptions of seven new species from India, Zootaxa 2119, pp. 1-22 : 17-21

Aturus indicus nov. sp.

( Figures 12 , 13 , 14A–D , 15A–C )

Type series. Holotype: male, dissected and slide-mounted in Hoyer's fluid. India: Himachal Pradesh State IND' 95/122 Kullu Valley, Karol Nala, 4 h trek from Naggar/Nishalla towards north, 2.200m asl., 06.vii.1995, leg. Panesar.

Females probably belonging to this species (not included in the type series): one female, same station as holotype, dissected and slide-mounted in Hoyer's fluid.

Diagnosis. Male: IV-Leg-2 long and ventrally curved; IV-Leg-3 with two long ventral swimming setae; IV-Leg-4 ventrodistally with two modified enlarged setae, the proximal one enlarged, blade-shaped and the distal one nearly straight and broad; IV-Leg-5 proximally with five thick and five slender setae; ventral shield with one larger ovoid, and one smaller circular modified setae on each side of the deep median cleft.

Description. Male: Dorsal and ventral shield present, these fused at posterior end; dorsal shield ( Fig. 12 ) bearing four pairs of dorsoglandularia, setae associated with the most anterior pair of dorsoglandularia longest; excretory pore located between third and fourth pair of glandularia; four pairs of lateroglandularia lying in the dorsal furrow, the three posterior of which are fused into one platelet; ventral shield L/W 425/351; ventral shield extending up onto dorsal side of body; dorsal surface of ventral shield with transverse row of small setae in posterior region, scattered longer setae on posterolateral surface and a row of longer setae on each posterior margin; posterior end of dorsum (actually dorsal portion of ventral shield) with a deep median cleft; ventral shield ( Fig. 13 ) with one larger ovoid, and one smaller circular modified setae on each side of the deep median cleft; 16–18 genital acetabula present on on each side. Palp ( Fig. 15B ): palp total L 239, dL and %L (in parentheses): P-1 18 (7.5), P-2 56 (23.4), P-3 45 (18.8), P-4 82 (34.3), P-5 38 (15.9), L P-2/P-4 0.68; P-2 with a ventrodistal projection.

Legs: III-Leg-5 ( Fig. 14D ) with 7–8 longer setae on the distal part of the ventral margin; IV-Leg-2 long and bowed; IV-Leg-3 with two long ventral setae; IV-Leg-4 ventrodistally with two modified enlarged setae which are approximately the same length as the fifth segment, the proximal one enlarged, blade-shaped and distal one nearly straight and broad; IV-Leg-5 proximally with five thick and five slender setae ( Fig. 14A–B ); L of IV-Leg-2-6 ( Fig. 14C ): 175, 150, 148, 123, 121.

Female: Dorsal and ventral shield present; dorsal shield bearing four pairs of dorsoglandularia; excretory pore lying near the posterior end of dorsal shield; dorsal shield L/W 331/275; ventral shield ( Fig. 15C ) L/W 381/345; suture lines between third and fourth coxae well developed; 13–16 genital acetabulae on each side; two pairs of glandularia lying immediately anterior to acetabular region; palp total L 234, dL and %L (in parentheses): P-1 22 (9.4), P-2 56 (23.9), P-3 41 (17.5), P-4 77 (32.9), P-5 38 (16.2), L P-2/P-4 0.73; structure of palp ( Fig. 15A ) similar to male.

Discussion. Aturus indicus sp. nov. is the third species of Aturus reported from India. The first one A. scutelliferus Walter, 1928 (known only from the Kangra Valley, Himachal Pradesh), together with A. indicus sp. nov., belong to the species group more typical of the Palaearctic which have a very complex chaetotaxy on the fourth leg of the male. The second one, A. hiatosomus Cook, 1967, known from Maharashtra State and Sri Lanka ( Gledhill & Wiles 1997), belongs to a species group more typical of the Oriental region ( Indonesia), which have a very simple chaetotaxy on the fourth leg and a row of short, peg-like setae at the posterior end of the body in the male.

The new species resembles Aturus crinitus Thor, 1902 (Europe), but it can be easily distinguished in the males by a different chaetotaxy of the fourth leg (compare Figures 14C and 15D ), e.g. the presence of two swimming setae on the vental margin of IV-Leg-3 (without setae in A. crinitus), IV-Leg-5 proximally with five thick and five slender setae (about 8 thick setae in A. crinitus). Further differences are found in a differently shaped modified seta on each side of the deep median cleft (one pair of larger ovoid, and one pair of smaller circular setae vs. two pairs of similarly shaped larger ovoid setae in A. crinitus) and the three pairs of glandularia lying separately in the dorsal furrow in A. crinitus.

Etymology. The species is named after the country where it was collected.

Habitat. Discovered in mosses in a mountain stream.

Distribution. Known only from the type locality in the Kullu Valley (Himachal Pradesh State) in the south-western Himalayas.

Figures

FIGURE 12. Aturus indicus sp. nov., male: idiosoma, dorsal view. Scale bar = 100 µm.

FIGURE 13. Aturus indicus sp. nov., male: idiosoma, ventral view. Scale bar = 100 µm.

FIGURE 14 A – D. Aturus indicus sp. nov., male: A = left IV-Leg- 4 - 6; B = right IV-Leg- 4 - 6; C = IV-Leg- 2 - 6; D = III- Leg- 5 and - 6. Scale Bars = 100 µm.

FIGURE 15 A – D. A – C Aturus indicus sp. nov. (B = male, A, C = female): A = palp, medial view; B = palp, lateral view; C = idiosoma, ventral view. D Aturus crinitus Thor, 1902, male, canyon of river Pċinja (Serbia): D = IV-Leg- 2 - 6. Scale Bars = 100 µm.