Fedrizzia grossipes Canestrini

Fedrizzia grossipes Canestrini, 1884: 707; Womersley, 1959: 15.

Diagnosis. Both sexes: idiosoma 900–918 long. Ventral and ventrianal shield with mesh-like reticulation; pedofossae III absent; CxIV-marginal suture absent; femur III and IV without lamellae, seta pv1 not significantly thickened; femur IV slightly elongated. Female: sternogynial shield could be smooth or reticulate, but not honeycomb-like, surrounded by a weakly defined smooth area. Male: sternoventral shield with suture well behind (CxIV–CxIV) genital opening, demarking anterior smooth and posterior reticulated areas.

Also with the following combination of measurements: posterior margin of sternal shield 324 wide; anterior margin of sternogynial shield 160, medial length 124; anal shield 324 wide, 135 long; male genital opening 72 wide, 51 long.

Remarks. The type specimens ought to be in Canestrini’s collection, but are no longer there (pers. comm., P. Nicolosi, University of Padua). Canestrini’s (1884) description and illustrations are enough to confirm that F. grossipes is a member of Fedrizzia, but are partially inadequate for determining whether F. grossipes is distinct from some other Fedrizzia species. Womersley (1959) thought he had collected a species distinct from F. grossipes, but Dr Max Sellnick thought Womersley’s new species and F. grossipes were conspecific. Therefore, Womersley (1959) chose not to describe the species, but rather compared it with F. grossipes.

From Womersley’s (1959) work, and these studies, F. grossipes is clearly not conspecific with F. sp. cf. grossipes. The size and shape of the body parts of fedrizziid mites are reasonably constant, as noted by Womersley (1959), and confirmed by this study. The idiosoma of F. grossipes is about 900–918 long and 594–612 wide, but that of F. sp. cf. grossipes is about 1160 long and 870 wide (Womersley 1959). Size differences of a similar magnitude are found in other body parts, such as the sternogynial shield, anal shield, and male genital opening. Here, I have regarded the mites described by Womersley as F. sp. cf. grossipes as conspecific with another of his species, F. s e l l n i c k i.

However, F. derricki (928 long, 660 wide) and F. bornemisszai (928–970 long, 730 wide) are of similar size as F. grossipes. These two species are distinguished from F. grossipes by having FeIV much longer than FeIII; in F. grossipes FeIII and FeIV are subequal, with FeIV appearing slightly larger. Additionally, the suture demarking the smooth and mesh-like reticulation of the male venter is between the bases of CxIV in F. grossipes, but lies directly behind the genital opening in F. d e r r i c k i and F. bornemisszai. Therefore, I consider F. grossipes a species distinct from all other known species of Fedrizzia.