? Mixtacandona sp.

(Fig. 8 C, D)

Limnocrene spring La Commenda, Trecasali, Parma. Coordinates: 44°53’15”N 10°16’57”E. Elevation: 34 m a.s.l. Collected on April 16, 2009 by GR. Subsequent surveys did not yield additional material of this taxon. Material examined. GR.564, one isolated LV (L = 735 µm, H = 458 µm) of adult ♀, no soft parts (Fig. 8 C,D). Distribution. Known only from the above-mentioned site.

Left valve with a scalene trapezoidal shape. Maximum height at anterior cardinal angle, maximum length below the muscle scars. Slightly convex dorsal margin with marked dorsal protuberance and cardinal angles. Anterior margin rounded, posterior margin slightly pointed. Ventral margin straight, with a slight convexity posteriorly. The central dorsal area is characterised by a horizontal depression. Surface covered by a pattern of pits (foveolae) on the whole surface. Interiorly, the marginal zone is narrow; the vestibules are equally developed; marginal pore canals not observed.

Remarks. This specimen is tentatively allocated to the taurica species-group of the genus Mixtacandona, because of the trapezoidal outline and reticulated surface of the valves. The general outline is very similar to that of M. talianae, which is smaller and lacks the surface ornamentation. The trapezoidal shape and the pattern of ornamentation are also shared with species of the zschokkei -group of the genus Pseudocandona Kaufmann, 1900 (for example, see Gidó 2010).