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

Pesic, Vladimir & Smit, Harry, 2007, Water mite species of the genus Hydrodroma Koch (Acari: Hydrachnidia, Hydrodromidae) from Australia. Part II, Zootaxa 1509, pp. 41-50 : 42-43

Hydrodroma wilesi sp. nov.

( Figs. 1 – 6 ; Tables 1 – 2 )

Type series: Holotype: female, dissected and slide mounted in Hoyer's fluid, NORTHERN TERRITORY, Kakadu National Park, Helocrene near Gunlom Plunge Pool, 30.ix.2005, 13° 25.17 S 132° 24.989 E ( NTM). Paratypes: one female ( NTM), same data as holotype; Outlet Upper Pool, Edith Falls, Katherine Gorge NP, 30.vii.1994, two males ( ZMAN, MNHP), one of them dissected and slide mounted in Hoyer's fluid.

Diagnosis: Characters of the genus Hydrodroma ; the basic shape and setation of coxae, genital field and palp are similar to those found in H. torrenticola ; 1 – 3 rather short swimming setae on anterior surface on III- L-5, number of swimming setae on III-L-4 1 – 2, on IV-L-5a 2 – 3 and on IV-L-5p 1, swimming setae are absent on the anterior surface of IV-L-5.

Description: Female (holotype, in parentheses some data for paratype): Length of idiosoma 1006 (1000), width 844 (831). Total number of coxal setae is 35 on coxae 1, 35 – 36 on coxae 2, 27 on coxae 3, 22 on coxae 4. Further details of genital plate morphology ( Fig. 2 ) are given in Table 1 . Gnathosoma: capitulum ( Fig. 5 ) 182 in length; chelicera total length 250, claw 50 in length. Palps without diagnostic features, for chaetotaxy of the palp see Fig. 4 (measurements in Table 1 ). Number of swimming setae on legs are presented in Table 2. Swimming setae on anterior surface on III-L-5 rather short.

Male: Length of idiosoma 1180, width 675. Total number of coxal setae varies between 31 – 35 on coxae 1, 37 – 38 on coxae 2, 27 – 28 on coxae 3, 21 – 22 on coxae 4. Further details of genital plate morphology ( Fig. 3 ) are given in Table 1 . Gnathosoma: capitulum 172 in length; chelicerae total length 170, claw 35 in length. Palps without diagnostic features, for measurements of the palp see Table 1 . Number of swimming setae on legs are presented in Table 2. Swimming setae on anterior surface on III-L-5 rather short.

H. w ilesi

Male (n=2) Female (n=2)

II-L-5 posterior 0 0

III-L-4 posterior 2 1–2 III-L-5 posterior 1–2 rather short 1–3 rather short IV-L-4 anterior 2–3 2–3 IV-L-4 posterior 3–4 2–3 IV-L-5 anterior 0 0

IV-L-5 posterior 1 1

Remarks: Hydrodroma wilesi sp. nov. is most similar to H. tonapii Cook ( India) and H. reinhardi Pesic (Mediterranean) , in the presence of relatively few swimming setae on IV-L-4 and 5, the absence of swimming setae on the anterior side of IV-L-5 and presence of relatively large claws on the legs ( Fig. 6 ). H. wilesi sp. nov. differs from H. reinhardi (in parentheses data taken from Pesic 2002) in a lower number of swimming setae on II-IV-L (III-L-4 2 – 5, III-L-5 2 – 5, IV-L-4a 2 – 7, IV-L-4p 2 – 6, IV-L-5p 2 – 5), a shorter ejaculatory complex (164 vs. 180 – 210 in H. reinhardi ) and rather shorter swimming setae on anterior surface on III-L-5. H. tonapii is distinguished by its relatively fewer setae on the coxal surfaces and presence of two swimming setae on posterior surface on IV-L-5 (see: Cook 1967 and remarks under H. tonapii ).

Etymology: The species is named after Dr Roy Wiles ( UK) in appreciation of his studies of the genus Hydrodroma .

Distribution: Australia (Northern Teritory).

Habitat: helocrene spring and stream.

Figures

FIGURES 1 – 6. Hydrodroma wilesi sp. nov. (1 – 2, 4 – 6 female; 3 male): 1 = coxal and genital field; 2 = genital field; 3 = genital field; 4 = palp, lateral view; 5 = capitulum and chelicera; 6 = I - L. Scale Bars = 100 µm.

Tables

TABLE 1. Morphometric data for the genital plate and palp for H. wilesi sp. nov. (abbreviations: r = range, n = number of mites examined).

	H. wilesi
	Male paratype	Female holotype
genital acetabula, n	41	52
number of genital setae	41-45	38
genital plate length	163	180
ejaculatory complex	164	-
length Μm P1	36	44
P2	53	62
P3	30	35
P4	130	150
P5	56	62
Palp, total L	305	353
%P1	11.8	12.5
%P2	17.4	17.6
%P3	9.8	9.9
%P4	42.6	42.5
%P5	18.4	17.6
W P-4	27	30