Species similar to Platyomus mollis in body shape and size. Platyomus bruchi distinguishes mainly because the vestiture is dark grey to dark brown, uniform on the pronotum and with three pale brown "v-shaped" stripes (usually with black maculae along them) on the elytra. It does not have large tubercles on the elytra.

Prosopis ruscifolia Griseb. (Fabaceae) (Lanteri et al. 2002a).

I is mainly associated with vegetation of the Chacoan biogeographic province.