Hydrodroma kununurra sp. nov

(Figs. 1–5, 9, 18; Tables 1–2)

Type series: Holotype: male, dissected and slide mounted in Hoyer's fluid, Lake Kununurra, 15°48 S 128°44 E, 10 km southeast of Kununurra, Western Australia, Australia, 19.ix.1998 (WAM). Paratypes: 42 specimens (WAM, ZMAN, MNHP), same data as holotype, five males and two females of these were dissected and slide mounted on Hoyer's fluid.

Diagnosis: Characters of the genus Hydrodroma; the basic shape and setation of coxae, genital field and palps are similar to that found in H. pilosa; genital plates with 70–93 acetabulae in 5–6 rows; the palpal segments are narrower; segments of the first leg proportionally long.

Description: Males (n = 5): Length of idiosoma 1025–1369, width 919–1269. Total number of coxal setae varies between 13–15 (=13.6) on coxae 1, 8–14 (=11.6) on coxae 2, 10–13 (= 11.2) on coxae 3, 12–17 (= 13.8) on coxae 4. Further details of genital plate morphology (Fig. 2) are given in Table 1. Gnathosoma: capitulum (Fig. 5) length 247–269 (= 261.8); chelicerae total length 365–394 (= 379), claw 69–86 long (=79.4). Palps without diagnostic features, the number of pennate mediodistal setae on P­2 varies between 3 and 4 (Fig. 3), for palp chaetotaxy see figures 3–4 (measurements in Table 1). Swimming setae on anterior surface on IV­L­5 rather short.

Character MALE FEMALE

H. kununurra Female (n = 2): Length of idiosoma 1019–1525, width 900–1375. Number of coxal setae varies between 12–15 on coxae 1, 12–13 on coxae 2, 10 on coxae 3, 12–14 on coxae 4. Gnathosoma: capitulum L 275–281; chelicerae total length 411–413, claw 86–91 in length. Further details of genital plate morphology (Fig. 18) are given in Table 1; egg maximum diameter 134–141.

Remarks: Hydrodroma kununurra sp. nov is most similar to H. pilosa Besseling in the number and distribution of swimming setae on legs and in morphology of the genital field. The primary difference between them lies in the proportions of the palp. Hydrodroma kununurra sp. nov. possesses much narrower palpal segments. In H. pilosa the palpal segments are much stockier, especially P­4 (compare Figs. 3–4 with Figs. 6–7). Furthermore, H. kununurra sp. nov., is distinguished by proportionally long segments of the first leg (compare Fig. 9 with Fig. 8) and a rather shorter swimming setae on anterior surface on IV­L­5.

Etymology: The species is named after Lake Kununurra .

Distribution: Australia (Western Australia). Habitat: Stagnant waters (lake).