It is one of the smallest species of Platyomus in Argentina (6mm long) along with P. dianae. Platyomus elegantulus differentiates by the cream to pale brown vestiture (in some specimens greenish), usually with stripes along the disc of pronotum and a pair of darker "v-shaped" stripes on elytra. In Misiones province there is a variety with several "v-shaped" thin light stripes on the elytra, that lack tubercles.

Acacia aroma Hook. & Arn., Acacia farnesiana (L.) Willd. and Prosopis sp (Fabaceae).

It is mainly associated with vegetation of the Paranaense and Chacoan biogeographic provinces.