Limnesia (Limnesia) maculata ( Müller, 1776 ), Muller, 1776

Yi, Tianci & Jin, Daochao, 2009, Water mites of the genus Limnesia Koch, 1836 (Acari: Hydrachnidia, Limnesiidae) from China, with description of four new species, Zootaxa 2234, pp. 21-38 : 26-29

Limnesia (Limnesia) maculata ( Müller, 1776)

Figure 3 , A–H, Figure 4 , A–F

Material examined Two males and six females from a pool, Buerjin County, Xinjiang Province, leg. Jin Daochao, 15 August 1997. One male and one female were dissected and slide-mounted.

Description Male Body soft and smooth, 1138 in length, 887 in width; O1 located on anterior end of body (lateral view), A1 below O1 (lateral view); lateral eyes separated, anterior-lateral eyes slender and longer than posterior-lateral ones; A2 slightly anterior to posterior-lateral eyes; O2 slightly anterior to D1; dorsum with a small plate between D3; coxae occupying about half the ventral surface; infracapitular bay V-shaped; CxI separated but close to each other; ACG with well developed posterior apodemes; ACG and PCG separated; E4 large with a long seta, confined to a triangular area formed by a bifurcation of the suture line between CxIII and CxIV; medial margins of CxIII round with small secondary sclerotization; distance between CxIII median angles (including the secondary sclerotization) 173; genital plates fused together at both ends, 281 in length and 314 in width; three pairs of genital acetabula, these somewhat ellipse in shape and occupying most of the surface of the genital plates; plates with setae scattered here and there, and a semi-circular row of setae stretching the middle of second pair; excretory pore located between V2; most of setae on dorsal and lateral side of P-II and P-III pinnate; P-IV with a long and two distal ventral setae and several lateral setae; dorsal lengths of P-I to P-V: 36, 124, 135, 240, 60; Figure 3 -G illustrating the proportion and chaetotaxy of the palp; protuberance on ventral surface of P-II cone-shaped, the peg-like seta process well down towards the posterior; chelicera 249 in length, chelicera claw 89 in length, Figure 3 -F illustrating the chelicera; legs well adorned with bristles; tips of IV-L-6 with a fine sate; all claws with one slender dorsal clawlet and one ventral thick clawlet; dorsal lengths of I-L-3 to 6: 126, 224, 250, 193; dorsal lengths of IV-L-3 to 6: 129, 167, 210, 189; III-L-4 with 8, III-L-5 with 10, IV-L-4 with 8, IV-L-5 with 11 and IV-L-6 with 4 swimming hairs.

Female Body soft and smooth, length 1450, width 1025; the shape of dorsum and coxae similar to male; coxae occupying more half the ventral surface; CxI with well developed posterior apodemes; medial margins of CxIII with well developed secondary sclerotization, distance between CxIII median angles (including the secondary sclerotization) 80; genital plates (including pregenital sclerite) 300 in length and 252 in width, outer edges of plates concave between first acetabula and second ones, inner edges with several setae, posterior-inner edge with a pair of well developed pouch with a long sate; the characters of palp similar to male; dorsal lengths of P-I to P-V: 41, 173, 138, 225, 61; III-L-4 with 9, III-L-5 with 10, IV-L-4 with 11, IV-L- 5 with 16 and IV-L-6 with 7 swimming hairs.

Remarks Limnesia maculata ( Müller, 1776) is a common Palaearctic species. Uchida (1941) reported the species without description from northeast China. The specimens in this study were collected from Xinjiang Province, northwest China, which belongs to Palaearctic region yet. Its genital plates with concave outer edge are similar to Wainstein’s specimens (1977). Its ventral P-IV with a long seta is different from Wainstein’s and Tuzovskij’s (1997) while similar to Soar & Williamson’s (1927) and Besseling’s (1964). To the best of our knowledge, the palp with pinnate setae is unknown in Limnesia maculata . Larva and Nymph see Soar and Williamson (1927) and Tuzovskij (1997).

Figures

FIGURE 3. Limnesia maculata (Müller, 1776), male, A—idiosoma, ventral view, B—idiosoma, dorsal view, Cidiosoma, lateral view, D—genital field, E—infracapitular, lateral view, F—chelicera, lateral view, G—palp, lateral view, H—IV-L- 5, 6. Bars = 100 Μm.

FIGURE 4. Limnesia maculata (Müller, 1776), female, A—idiosoma, ventral view, B—idiosoma, dorsal view, Cgenital field, D—palp, lateral view, E—I-L- 5, 6, F—IV-L- 5, 6. Bars = 100 Μm.