Arrenurus Dugès, 1834

Gerecke, Reinhard, 2009, Revisional studies on Thoracophoracarus K. Viets, 1914 (Arachnida, Acari, Hydrachnidia, Arrenuridae), Zoosystema 31 (1), pp. 127-145 : 129

Genus Arrenurus Dugès, 1834

TYPE SPECIES. — Arrenurus viridis Dugès, 1834 .

Arrenurus sinearcus K. Viets, 1924 species incerta ( Fig. 1 )

Arrenurus sinearcus K. Viets, 1924: 81 , figs 17-19.

Thoracophoracarus sinearcus – K. Viets, 1928: 48, fig. 116.

HOLOTYPE. — Germany, Holstein , Grosser Plöner See, 14.X.1918, A. Thienemann leg., 3082, ♂ ( SMF).

REMARKS

Notwithstanding intensive investigation of the water mite fauna in central European lowlands, this species has not been recorded since its first description, and K. O. Viets (1962) proposed that it could be a deformed representative of an Arrenurus species. In fact, from a careful re-examination it is obvious that the caudal part of the idiosoma is not symmetrical, as suggested by the figures for the original description. An evident asymmetry concerns the position of the gland openings posterior to the anal pore, the two membranes extending in the caudal concavity and the petiole that shows a distinct indentation on the right side ( Fig. 1 ). Obviously, this is a deformed specimen – with a high probability, the absence of the dorsal furrow, a character never observed again in European arrenurids, is due to monstruous development as well. Due to these morphological abnormalities, synonymization with one of the numerous Arrenurus species recorded from the Grosser Plöner See is not possible and Arrenurus sinearcus must be considered a species incerta.

Figures

FIG. 1. — Arrenurus sinearcus K. Viets, 1924, holotype ♂ (SMF), caudal area in dorsal view. Scale bar: 100 μm.