Arrenurus (Truncaturus) indentatus, Smit, Harry, 2010

Smit, Harry, 2010, Australian Arrenurus (Acari, Hydrachnidia) with the description of eleven new species, Zootaxa 2541, pp. 1-26 : 22

Arrenurus (Truncaturus) indentatus n. sp.

( Figs. 14A–C )

Material examined. Holotype male, Small lake near Diggers Creek, Mt. Kosciuszko NP, New South Wales, Australia, 36° 21.589 S 148° 29.248 E, alt. 1511 m, 5 December 2003 (AMS).

Diagnosis. Posterior idiosoma margin with a shallow indentation.

Description. Male: Idiosoma 859 long and 543 wide, greenish, anterior idiosoma margin rounded. Dorsal shield incomplete, 405 wide, dorsal furrow reaching to (or almost to) lateral idiosoma margin. D2 and D3 close to each other. Posterior idiosoma margin with a shallow indentation ( Fig. 14A ). Setae between D4 and posterior idiosoma margin bifurcated. Cauda indistinctly set off from remainder of idiosoma. Anterior coxae not extending to anterior idiosoma margin. Gonopore 36 long. Genital field straight and broad, extending to lateral idiosoma margin ( Fig. 14B ). Lengths of PI-PV: 28, 78, 56, 82, 38; PII medially with four setae ( Fig. 14C ). Lengths of I-leg-4-6: 104, 118, 102. Lengths of IV-leg-4-6: 144, 164, 166; IV-leg-4 with a long spur with two heavy setae. Legs 1–3 with numerous long setae, but without swimming setae; only fourth legs with numerous true swimming setae.

Female: Unknown.

Etymology. Named for the indentation of the posterior idiosoma margin.

Remarks. The new species is close to A. haswelli Cook from Tasmania, but has a longer dorsal furrow extending (almost) to the lateral idiosoma margin and the indentation of the posterior idiosoma margin is shallow (deep in A. haswelli ). Both species have a reduced number of swimming setae.

Figures

FIGURE 14 A – C. Arrenurus indentatus n. sp., holotype male: A = dorsal view; B = ventral view; C = palp. Scale bar A – B = 200 µm; C = 50 µm.