Arrenurus tenuicollis acornutus K.O. Viets, 1968

Smit, Harry, 2020, New records of the water mite genus Arrenurus Dugès, 1834 from South America (Acari: Hydrachnidia: Arrenuridae), with the description of five new species and one new subspecies, Acarologia 60 (2), pp. 371-389 : 386

Arrenurus tenuicollis acornutus K.O. Viets, 1968

Material examined— Argentina. Buenos Aires Province: 1/4/0, pond along Ruta 76, 2 km

S of crossing with Ruta 86, 37°23’22,64” S, 61°0’14,81” W, 10-xii-1999.

Remarks — The male specimen agrees well with the description of K.O. Viets (1968) in the large size, the anterior part of the idiosoma is distinctly set off from the idiosoma and IV-leg-4 has a short, rounded spur. The humps near the anterior idiosoma margin are a bit more pointed in the specimen from Argentina. An almost similar species, A. tenuicollis orthocercus Lundblad, 1944 , is described from Brazil. The latter species has larger posterior extensions of the cauda and the anterior part of the idiosoma is not set off from the idiosoma. The female of this subspecies have not been described, but the females of this study are similar to the description given for A. tenuicollis orthocercus . Arrenurus tenuicollis K. Viets, 1936 is a highly variable species, thus far with six subspecies described. Whether these subspecies all belong to the nominate taxon should be examined by molecular studies.

Distribution — Previously known from Chile only (K.O. Viets 1968).