Diagnosis.--Key characters: Ommatidial size coarse (Fig. 39b); prosternal process not planar, expanded apically (Fig. 18); mesal antennal spines present, although very minute; pronotum with inconspicuous impunctate regions and without rugosities or large confluent punctures; pronotum wider than long (Fig. 41e); femoral carinae absent; procoxal cavities widely open laterally (Fig. 17); lateral projections into mesocoxae from mesosternum absent (Fig. 20); mesal mesofemoral apices rounded or dentiform (Figs. 25b, 26d); tibial carinae apparently absent; elytral apices without spines, rounded to suture (Fig. 41e); pronotum with uniform granulate punctures; elytra with large, deep punctures basally, diminishing in size and depth apically; integument covered with dense, short pubescence; long flying-hairs mesally on antennae. Length: 9 mm.

Distribution and Diversity.--Brazil. Monotypic.

Discussion.--More specimens are needed before a thorough characterization of the genus can be made. I hypothesize that Atharsus may belong near the trichotomy allied to the Mallocera and allies clade (Fig. 59) and the Sphaerion and allies clade (Fig. 60). It may in fact be closely related to Parasphaerion, to which it approaches in the key characteristics. The wide, granulate pronotum without asperites and unarmed elytral apices distinguish it from Parasphaerion.