Bharatohydracarus robustus, Gerecke, 2004

Gerecke, Reinhard, 2004, Water mites from spring- and ground-water habitats in the Sultanate of Oman, Journal of Natural History 38 (22), pp. 2833-2849 : 2844-2846

Bharatohydracarus robustus sp. nov. ( figures 7 , 8 )

Type series. HOLOTYPE: „, OMAN 96-88. Wadi Darwat , Bou-Rouch-pump in muddy gravel, probe 80 cm below sediment surface; UTM 0228930/1893635 (17‡06'40̎N, 54‡27'09̎E), 29.6‡C, 771 M S cm 21, 4 April 1996.

Diagnosis. Male (female unknown) idiosoma large and robust (total L 1000, dorsal shield L 900); III-L and IV-L exhibiting strong modifications (a tuft of long hairs on a ventrodistal extension of III-L-3, a strong, curved ventral seta in the centre of III-L-4, two strong, club-shaped ventrodistal setae on III-L-5, dorsal margin of III-L-6 basally concave, IV-L with numerous fine hairs, segments 2–4 strongly thickened, IV-L-3 with a ventrodistal projection, IV-L-5 with a group of short and stout setae and a row of long ‘swimming’ hairs); palpus slender.

Description. Male (female unknown): idiosoma L/W 1000/720, ventral view figure 7A ; dorsal shield ( figure 7B ) L/W 900/600; maximum W Cx-3 510, Cx-4 610; leg claws with ventral clawlet and claw blade; measurements (segments 1–6 L/H) III-L 80/54, 180/64, 128/92, 112/80, 200/65, 225/42; IV-L 180/100, 185/165, 200/165, 215/158, 165/82, 220/50; III-L ( figure 8A ) and IV-L ( figure 8B ) with particular modifications in shape and setation as depicted in the figures and

described in the diagnosis; genital field triangular, L/W 195/215, bearing about 30 setae on each side; gonopore large, L/W 146/58, about 15 acetabula on each side arranged on a sclerite stripe; lateral and ventral glandularia accompanied by particularly long setae; gnathosoma ( figure 8C ) flattened, ventral L 130, a group of bifurcated fine hairs surrounding the mouth opening; chelicera with a thickened basal segment; palp slender, measurements of segments P-1–5 L/H 33/35, 90/55, 52/50, 80/43, 50/18.

Discussion. All species of the genus so far known have fewer genital setae, and the acetabula in the male gonopore arranged in more than one line on each side. However, the apparent presence of a single line only in B. robustus could be caused by folding inwards of the acetabula-bearing stripes, possibly due to

preservation of the specimen in ethanol. Probably, they are seen in tangential view, and really bear more than one row of acetabula. More or less distinct particularities in shape and setation of male III/IV-L have been observed also in B. latus Imamura, 1959 from Japan, and B. elongatus , B. schwoerbeli , B. orientalis , B. imamurai , B. similis and B. phreaticus , all described from India by Cook (1967). Apart from respective particular differences in setation, in all these species, thickening of IV-L-2–4 is less intensive, and the dorsal margins of the terminal segments are straight or convex, but not concave. Bharatohydracarus robustus differs furthermore from all species described in the genus in particularly large idiosoma dimensions.

Figures

FIG. 7. Bharatohydracarus robustus sp. nov., male (OMAN 96-88). (A) Idiosoma, ventral view; (B) dorsal shield. Scale bar: 100 Mm.

FIG. 8. Bharatohydracarus robustus sp. nov., male (OMAN 96-88). (A) III-L; (B) IV-L; (C) gnathosoma with chelicera and right palp in medial view. Scale bars: 100 Mm.