Hydrodroma australis, Pesic, Vladimir & Smit, Harry, 2007

Pesic, Vladimir & Smit, Harry, 2007, Water mite species of the genus Hydrodroma Koch (Acari: Hydrachnidia, Hydrodromidae) from Australasia. Part I, Zootaxa 1389, pp. 31-44 : 35-38

Hydrodroma australis sp. nov.

( Figs. 10–13 , 19 ; Tables 3–4 )

Type series: Holotype: male, dissected and slide mounted in Hoyer's fluid, Moore River, 31°21 S 115°29 E at crossing with Brandt's Highway, Regans Ford, Western Australia, Australia, 26.viii.1994 ( WAM). Paratypes: 16 males, 7 females same data as holotype ( WAM, ZMAN, MNHP), five males and two females of these were dissected and slide mounted on Hoyer's fluid.

Further records: AUSTRALIA: VICTORIA: Betka River at crossing with Stony Creek Road, southwest of Genoa, 24.x.1997, 37°36 S 149°39 E, 2 males, 2 females; QUEENSLAND: Hann Crossing (flowing), Lakefield NP, 15°04 S 144°08 E, 5.ix.2000, 1 female; Rock Pool Porcupine Creek, Porcupine Gorge NP, 23.x.2005, 20° 21.039 S 144° 27.952 E, 3 males; Porcupine Creek, Porcupine Gorge NP, 23.x.2005, 19° 49.125 S 166° 03.771 E, 7 males, 7 females; Mt Carbine Dam, Mt Carbine, 14.x.2005, 16° 32.019 S 145° 07.525 E, 21 specimens; Fruit Bat Falls, Cape York Peninsula, 11.ix.2000, 15°00 S 143°00 E, 1 female; NEW SOUTH WALES: Colo River at crossing with Putty Road, 01.xii.2003, 33° 25.259 S 150° 49.688 E, 9 males, 14 females, 7 deutonymphs. WESTERN AUSTRALIA: Fortescue Falls (pool), Hamersley Range NP, 11.viii.1994, 22°28 S 118°33 E, 8 females; Python Pool, Millstream Chichester NP, 7.viii.1994, 21°20 S 117°14 E, 3 males; Jack’s Waterhole (along Gibb River Road, 16°25 S 126°26 E), 14.ix.1998, 4 males, 2 females; Plunge Pool, Cathedral Falls, Purnululu NP (17°21 S 128°37 E), 24.ix.1998, 1 female; Lily Creek Lagoon, Kununurra , 17.ix.1998, 15°46 S 128°44 E, 11 males, 8 females, 2 deutonymphs; Pool Lennard River, east side Windjana Gorge, Windjana Gorge NP, 10.ix.1998, 17°21 S 124°20 E, 5 females; Pools in creek at Old Halls Creek, south of Halls Creek, 26.ix.1998, 18°14 S 127°46 E, 2 males, 2 females; Pond Dales Gorge, 22°28 S 118°37 E, Hamersley Range NP, 12.viii.1994, 1 male, 1 female; Western part Deep Reach pool, Millstream­Chichester NP, 16.viii.1994, 21°36 S 117°06 E, 4 females; Jackeroo Waterhole, El Questro Station, 16°00 S 127°58 E, The Kimberley, 15.ix.1998, 1 male, 1 female; Geikie Gorge, western side, Geikie Gorge NP, 28.ix.1998, 18°01 S 125°45 E, 2 females; Crossing Pool, Millstream­Chichester NP, 28.viii.1994, 21°34 S 117°05 E, 8 females; Middle Springs, west of Kununurra , 18.ix.1998, 24°42 S 116°51 E, 46 specimens. TAS­ MANIA: Apsley River (41° 51 S 148° 0 8 E) at crossing with Tasmania Highway, 19.x.1997, 2 females; Little Waterhouse Lake, Waterhouse Protected Area, 21.x.1997, 40°52 S 147°36 E, 1 male; Old river branch Coal River, 42°28 S 147°24 E, north of Richmond, 17.x.1997, 1 female; Reservoir of Darlington, Maria Island NP, 42°39 S 148° 0 5 E, 18.x.1997, 2 males, 6 females.

Character MALE FEMALE

H. australis male (n = 10) female (n = 5)

II­L­5 posterior 4–6 3–6 III­L­4 posterior 11–14 9–12 III­L­5 posterior 7–9 6–10 IV­L­4 anterior 9–12 7–9 IV­L­4 posterior 8–12 7–12 IV­L­5 anterior 2–4 2–4 IV­L­5 posterior 6–8 4–8

Diagnosis: Characters of the genus Hydrodroma ; the basic shape and setation of coxae, genital field and palp are similar to those found in H. pilosa ; genital plates with 32–49 acetabula in 3–4 rows; ejaculatory complex L 188–209; number of swimming setae on II­L­5p<7,0 III­L­5<10, on IV­L­5a<5 and on IV­L­5p<10.

Description: Males (n = 5, Moore river): Length of idiosoma 850–1019, width 780–894. Total number of coxal setae varies between 18–20 (= 19) on coxae 1, 18–28 (= 21.8) on coxae 2, 16–22 (= 18.5) on coxae 3, 15–21 (= 17.8) on coxae 4. Further details of genital plate morphology ( Fig. 11 ) are given in Table 3 . Gnathosoma: capitulum ( Fig. 13 ) length 209–237 µm (= 221); chelicerae total length 286–316 (= 305), claw 59–63 long (= 60.8). Palps without diagnostic features, for chaetotaxy of the palp see Fig. 12 (measurements in Table 3 ). Number of swimming setae on legs are presented in Table 4. Swimming setae on anterior surface on IV­L­5 rather short.

Female (n = 2, Moore river): Length of idiosoma 881–1063, width 850–894. Number of coxal setae varies between 17–22 on coxae 1, 17–20 on coxae 2, 16–19 on coxae 3, 12–15 on coxae 4. Gnathosoma: capitulum L 247–259; chelicerae total length 303–319, claw 63 long.

Remarks: Hydrodroma australis sp. nov is most similar to H. kununurra sp. nov. in the presence of more than 1 swimming setae on II­L­5 and swimming setae on the anterior surface of IV­L­5. Hydrodroma australis sp. nov. differs from H. kununurra sp. nov. in its minor idiosoma and gnathosoma dimensions (e.g. in H. kununurra sp. nov. idiosoma L males 1025–1369, females 1019–1525; L genital plates 216–236, L capitulum males 247–269, palp total L males 503–553) and in a smaller number of swimming setae on II­IV­L (in H. kununurra sp. nov. II­L­5p> 6, III­L­5> 10, IV­L­5a> 4). Furthermore, H. australis sp. nov. is distinguished by its relatively fewer acetabula (32–49 in generally 3–4 rows vs. 70–93 in 5–6 rows in H. kununurra sp. nov.), while the ejaculatory complex is shorter (188–209 vs. 216–236 in H. kununurra sp. nov.).

Etymology: The species is named for its southern occurrence.

Distribution: Australia (Victoria, Tasmania, New South Wales and Western Australia).

Habitat: Most specimens were taken from standing waters or slow running streams.

Figures

FIGURES 10 – 13. Hydrodroma australis sp. nov., male holotype (WA Moore River): 10, coxal and genital field; 11, genital field; 12, palp, medial view; 13, capitulum. Scale Bars = 100 µm.

FIGURES 18 – 20. Genital field: 18, H. kununurra sp. nov.; 19, H. australis sp. nov.; 20, H. kakadu sp. nov. Scale Bar = 100 µm.

Tables

TABLE 3. Morphometric data for the genital plate and palp for H. australis sp. nov. (abbreviations: r = range, n = number of mites examined).

mean	r	n	mean	r	n
genital acetabula, n 37.9	32–49	6	38	37–39	2
genital setae, n 27.3	26–32	6	25.5	24–27	2
genital plate length, m 197	189–208	6	182.5	179–186	2
ejaculatory complex length, m 202	188–209	6	–	–	–
P1 46.3	46–47	5	46.5	46–47	2
P2 83.5	79–86	5	81	79–83	2
P3 40	38–42	5	46.5	46–47	2
P4 192.7	181–200	5	198	191–205	2
P5 80.3	77–82	5	79.5	78–81	2
Palp, total L 443	430–456	5	451.5	444–459	2
%P1 10.4	10–10.9	5	10.3	10.2–10.4	2
%P2 18.9	18.3–19.5	5	17.95	17.8–18.1	2
%P3 9	8.8–9.2	5	10.3	10–10.6	2
%P4 43.5	42.1–44.2	5	43.85	43–44.7	2
%P5 18.2	17.9–18.7	5	17.6	17–18.2	2
W P­4 42.5	42–44	5	44	42–46	2