Albaxona indica, Pesic, Vladimir & Reddy, Yenumula Ranga, 2009

Pesic, Vladimir & Reddy, Yenumula Ranga, 2009, New records of water mites (Acari: Hydrachnidia) from interstitial freshwaters of India, with descriptions of three new species, Zootaxa 2158, pp. 20-32 : 26-29

Albaxona indica sp. nov.

( Fig. 3–5 )

Material examined. Holotype: male, dissected and slide-mounted in Hoyer's fluid. India, Andhra Pradesh State, West Godavari District, Potavaram village, 16°56' N, 81°24' E, hyporheic zone of the River Yerrakaluva (dissolved oxygen 4.9 ppm; pH 7.9; salinity 0.38 ppt; conductivity 595 µS; total dissolved salts 330 ppm; turbidity 6.1 NTU), tributary of the River Godavari, 2 October 2008. Paratypes: one male, dissected and slide-mounted in Hoyer's fluid, Andhra Pradesh State, Krishna District, Vijayawada city at the southern end of Kananaka Durga Varadhi, a roadway across the River Krishna, 16°29'13" N, 80°37'38.6" E, hyporheic zone of the River Krishna (water temperature 31o C; pH 8.0), July 2008; one female, dissected and slidemounted in Hoyer's fluid, Andhra Pradesh State, East Godavari District, Angara village, 16°46'16" N, 81°56'0" E, hyporheic zone of the River Godavari (water temperature 27o C; pH 6.0), 2 October 2008.

Additional records. Andhra Pradesh State: East Godavari District, Atreyapuram village, 17°24'15.6" N 80°51'46" E, 42 m asl., hyporheic zone of the River Godavari, 27 February 2007, one female (dissected and slide-mounted in Hoyer's fluid); Visakhapatnam District, Yeddevari Lova lagoon, 28 km from Elamanchil town, 17°33'0" N, 82°52'0" E, brackish water, 20 February 2007, one female (damaged, palps missing).

Diagnosis. Small idiosoma dimensions (e.g. dorsal shield L/W: 208–244/101–120 µm in male, 205/97 µm in female); P-4 ventral margins distinctly convex; postocularia away from the level of the first pair of glandularia; glandularia (V3 sensu Wiles 1997a) situated in posterolateral part of the ventral shield in female; IV-Leg-5 ventral margin straight, with two ventral setae near middle of segment.

Description. Male (holotype, in parentheses measurements of the paratype): dorsal shield ( Fig. 3A ) L/W 244 (208)/120 (101); bearing four pairs of glandularia and postocularia, the fourth pair reduced to a single seta; glandularia flanking the dorsal shield small; ventral shield (including genital field) ( Fig. 3B ) L/W 283 (233)/188 (139), capitular bay L 63 (46); anterior coxae projecting; third coxae triangular; genital field fused with ventral shield; three pairs of genital acetabula, these arranged in an obtuse triangle, width between outer edges of lateralmost pair of acetabula 67 (53); gonopore large 31 (27) in width; an area of soft integument extending posterior to the genital field, the excretory pore and a pair of glandularia lying in this soft integument. Palp ( Figs. 4 B-C): total L 140 (124), L: P-1 14 (14), P-2 35 (29), P-3 23 (20), P-4 45 (39), P-5 23 (22); %L: P-1 10.0 (11.3), P-2 25.0 (23.4), P-3 16.4 (16.1), P-4 32.1 (31.5), P-5 16.4 (17.7); L P-2/P-4 ratio 0.78 (0.74); capitulum ( Fig. 4D ) ventral L 60 (56); chelicera total L 98 (80). Legs: L of I-Leg ( Fig. 4E ): 21 (24), 24 (24), 39 (34), 56 (52), 63 (58), 60 (61); IV-Leg ( Fig. 4F ): 47 (47), 41 (35), 50 (41), 58 (48), 67 (59), 60 (55); IV-Leg-5 ventral margin straight, with two ventral setae near middle of segment; swimming setae absent.

Female: dorsal shield L/W 205/97; structure of dorsal shield ( Fig. 5A ) similar to male; ventral shield L/W 209/197; a ventral shield with a relatively deep genital bay; glandularia (V3 sensu Wiles 1997a) situated in posterolateral part of the ventral shield; genital field not fused with the ventral shield; three pairs of acetabula, these arranged in a line; the individual acetabular plates L 32, width between outer edges of lateralmost pair of acetabula 92; a pair of glandularia lying immediately anterior to the genital field. Palp ( Figs. 5C ): L (P-2-4): P-2 30, P-3 19, P-4 39, P-5 23; L P-2/P-4 ratio 0.77; chelicera total L 80. Legs: L of I-Leg: 22, 23, 35, 50, 58, 58; IV-Leg ( Fig. 5D ): 46, 33, 44, 49, 59, 56; leg and palp chaetotaxy as in the male.

Discussion. The new species is the second representative of the genus Albaxona in India. So far, only A. stoka Cook, 1967 has been reported from interstitial waters in Maharashtra State. Lundblad (1971) described A. stoka javanica from eastern Java.

Compared with A. stoka (in parentheses data taken from Cook 1967), A. indica sp. nov. differs in the following features: smaller idiosoma (e.g., dorsal shield L/W: 300-319/145-152 µm in male, 327-358/160-167 µm in female); P-4 ventral margins distinctly convex (straight in A. stoka ); postocularia well away from the level of the first pair of glandularia (adjacent in A. stoka ); anterior margin of dorsal shield more pointed (rounded in A. stoka ); postgenital sclerite and excretory pore in female not fused with the extreme posterior end of the dorsal shield (fused in the female of A. stoka ); the glandularia (V3 sensu Wiles 1997a) situated in females of other members of the genus Albaxona , more or less halfway between insertion of the fourth legs and genital field, are shifted in the female of A. indica sp. nov. to the posterolateral part of the ventral shield; IV-Leg-5 ventral margin straight, with two ventral setae near middle of segment (IV-Leg-5 very slightly bowed, with three ventral setae near middle of segment in male of A. stoka ).

Albaxona kurtvietsi Gledhill & Wiles, 1997 , described from Sri Lanka, can be easily distinguished from A. indica sp. nov. by the presence of a cauda-like posterior projection in males which appears to be unique within the genus ( Gledhill & Wiles 1997).

Etymology. Named after the country of the type locality. Habitat. Interstitial waters.

Distribution. Known from three localities in Andhra Pradesh State.

Figures

FIGURE 3 A – B. Albaxona indica sp. nov., male holotype: A = idiosoma, dorsal view; B = idiosoma, ventral view. Scale bar = 100 µm.

FIGURE 4 A – F. Albaxona indica sp. nov., male (B, F holotype, A, C – E paratype): A = posterior part of idiosoma, ventral view; B = right palp, lateral view; C = left palp, medial view; D = capitulum and chelicera; E = right I-Leg; F = right IV-Leg. Scale bar = 100 µm.

FIGURE 5 A – D. Albaxona indica sp. nov., female: A = idiosoma, dorsal view; B = posterior part of idiosoma, ventral view; C = left palp (P- 1 missing), medial view; D = right IV-Leg. Scale bar = 100 µm