Arrenurus (Megaluracarus) rotundicaudatus, Smit, Harry, 2010

Smit, Harry, 2010, Australian Arrenurus (Acari, Hydrachnidia) with the description of eleven new species, Zootaxa 2541, pp. 1-26 : 15

Arrenurus (Megaluracarus) rotundicaudatus n. sp.

( Figs. 10A–D )

Material examined. Holotype male, Ewans Pond 1, Ewans Ponds Conservation park, South Australia, Australia, 38° 0 1.566 S 140° 47.434 E, 4 April 2008 ( SAM). Paratype: female, same data as holotype ( SAM).

Diagnosis. Male: Cauda posteriorly rounded, D2 and D3 located close to each other, idiosoma conspicuously blue. Female: Idiosoma conspicuously blue, genital plates short, slightly geniculated, gonopore with triangular sclerotized patches.

Description. Male: Idiosoma elliptical, narrowed posteriorly, 753 long and 518 wide, conspicuously blue, legs brown. Dorsal shield 518 wide, D2 and D3 close to each other. Cauda indistinctly set of from idiosoma, rounded posteriorly with a pair of two short setae between D4 and posterior margin ( Fig. 10A ). Capitular bay shallow. First coxal plates extending to anterior idiosoma margin. Gonopore 62 long. Genital plates long and narrow, extending to lateral idiosoma margin ( Fig. 10B ). Lengths of PI-PV: 28, 64, 41, 70, 34. Medial side of PII with three setae, one located more dorsally and the other two near anterior margin of segment ( Fig. 10C ). Lengths of I-leg-4-6: 100, 108, 110. Lengths of IV-leg-4-6: 140, 170, 170. IV-leg-4 with a short, strongly tapering spur.

Female: Idiosoma 859 long and 680 wide, conspicuously blue, legs brown. Dorsal shield complete, 753 long and 559 wide, D2 and D3 not close to each other. Anterior idiosoma margin rounded. First coxal plates extending to anterior idiosoma margin. Medial margin of third and fourth coxal plates more or less of equal length, directed somewhat oblique, distance between third coxal plates less then width of one genital valve. Gonopore 170 long and 180 wide, genital valves anteriorly and posteriorly with triangular chitinized patches, which are connected medially. Genital plates short and narrow, somewhat geniculated laterally ( Fig. 10D ), genital field 100 wide. Lengths of PI-PV: 32, 62, 46, 72, 36; palp as in male. Lengths of I-leg-4-6: 106, 114, 102. Lengths of IV-leg-4-6: 146, 154, 160.

Etymology. Named for the rounded cauda of the male.

Remarks. The rounded posterior margin of the cauda in combination with closely located glandularia D2 and D3 will easily separate the new species from other species of the genus. The only species somewhat close, A. simplicicauda Lundblad from Burma, has the posterior margin of the cauda with a lateral indentation, and D2 and D3 distanced.

Figures

FIGURE 10 A – D. Arrenurus rotundicaudatus n. sp., (A – C holotype male, D paratype female): A = dorsal view; B = ventral view; C = palp; D = ventral view. Scale bars A – B, D = 200 µm; C = 50 µm.