Unionicola (Downesatax) longipalpis, Smit, Harry, 2008

Smit, Harry, 2008, Australian Unionicola (Acari: Hydrachnidia: Unionicolidae), with the description of two new subgenera and eight new species, Zootaxa 1674, pp. 1-26 : 8-9

Unionicola (Downesatax) longipalpis n. sp.

( Figs. 8–11 )

Material examined. Holotype female: Lily Pond Falls, Katherine Gorge NP (= Nitmiluk NP), Northern Territory, Australia, 14° 18.801 S 132° 28.326 E, 27 July 1994 ( NTM). Paratypes: Northern Territory: 3 females ( NTM, ZMAN), same data as holotype; 1 female, pond in Jim Jim Creek, at Jim Jim Crossing, Kakadu NP, 22 July 1994 ( ZMAN); 2 males, 5 females, plunge pool Barramundie Creek, Kakadu NP, 13° 19’07.56”S 132° 26’16.61”E, 24 July 1994 ( ZMAN). Western Australia: 1 female, pond Dales Gorge, Hamersley Range NP, 22° 28’37.53”S 118° 33’26.66”E, 12 August 1994 ( WAM); 1 male, 3 females, pond Kalamina Gorge near falls, Hamersley Range NP, 22° 24’48.08” S 118° 24’34.50´E, 13 August 1994 ( WAM, ZMAN); 1 male, pond Knox Gorge, Hamersley Range NP, 22° 22’12.39” S 118° 17’51.81” E, 13 August 1994 ( WAM); 1 female, Ashburton River at crossing with North West Coastal Highway, Western Australia, 22° 32’ 38.17” S 115° 29’ 54.14” E, 18 August 1994 ( WAM). Queensland: 2 females, Gregory River at Gregory Downs, 18° 38.811 S 135° 15.008 E, 11 October 2005 (QM).

Other material. Queensland: 1 male, 1 female, Fruit Bat Falls, Cape York Peninsula, 11 September 2000. Northern Territory: 4 males, Lily Pond Falls, Katherine Gorge NP (= Nitmiluk NP), 14° 18.801 S 132° 28.326 E, 27 July 1994; 2 males, Home Billabong, Kakadu NP, 22 July 1994; 2 females, Manton Dam, 12° 51.726 S 131° 0 7.148 E, 24 September 2005. Western Australia: 1 female, Python Pool, Millstream- Chichester NP, 21° 20’0.88”S 117° 14’18.89”E, 17 August 1994; 3 females, Fortescue River, at crossing with North West Coastal Highway, 21° 17’36.95”S 116° 8’38.63”E, 18 August 1994; 3 males, 2 females, Spillway Creek, near Lake Argyle, 20 September 1998.

Diagnosis. Posteroventral peg-like seta of PIV on a distinct tubercle, PIV long (>100 µm in female,> 80 µm in male); IV-leg-6 long (>220 µm in female,> 200 µm in male).

Description. Female: Idiosoma 389 (365–482) long and 275 (267–373) wide. Posterior apodemes of anterior coxal plates extending just beyond anterior margin of third coxal plates. Length of third + fourth coxal plates 130. A pair of glandularia lying in the secondary sclerotisation of the posteromedial corners of the fourth coxal plates; associated setae of these glandularia long. Coxal plates with an elongated reticulate pattern. Genital field terminal, with five pairs of acetabula placed on two pairs of genital plates. Anterior plate with two acetabula and an elongated medial flap with two long, enlarged setae. Posterior genital plate with one long, enlarged seta. Genital field flanked by a pair of glandularia on a large tubercle. Lengths of PI-PV: 12, 93, 51, 104, 78. Palp long and slender, L/H of PIV 4.7, PIV with one long and slender setal tubercle, other seta on a low tubercle. Posteroventral peg-like seta of PIV on a distinct tubercle. Lengths of I-leg-4-6: 222, 210, 134. I-leg-6 slightly bowed, first leg with long, somewhat pointed setae, these setae smooth. Lengths of IV-leg-4-6: 239, 332, 239; IV-leg-4 and -5 with three swimming setae, IV-leg-3 with one swimming seta. Claws with clawlet, without claw blade.

Male: Idiosoma 332 (356–409) long and 243 (259–324) wide. Posterior apodemes of anterior coxal plates extending just beyond anterior margin of third coxal plates. Length of third + fourth coxal plates 134. A pair of glandularia lying in the secondary sclerotisation of the posteromedial corners of the fourth coxal plates; associated setae of these glandularia long. Coxal plates with an elongated reticulate pattern. Genital field not fused ventrally, with five pairs of acetabula. Genital field flanked by a pair of glandularia on a large tubercle. Lengths of PI-PV: 8, 81, 32, 82, 56. Palp as in female, L/H PIV 4.1. Lengths of I-leg-4-6: 183, 184, 114. Lengths of IV-leg-4-6: 206, 250, 208. Legs as in female.

Etymology. Named for its long palp.

Remarks. The new species is close to U. minutissima Lundblad , but differs in a longer palp, with the posteroventral peg-like seta of PIV on a distinct tubercle, and in longer leg segments. PV of the female is 60–78 µm long in the new species and 41–46 µm in U. minutissima . IV-leg-6 of the female is 227–239 µm in U. longipalpis n. sp. and 149–173 µm ( Cook 1986) in U. minutissima .

Figures

FIGURE 8 – 11. Unionicola longipalpis n. sp. 8 – 10, holotype female, 8, ventral view; 9, palp; 10, I-leg- 4 - 6; 11, paratype male, ventral view. Scale bars = 50 µm.