Stropenron Johnson, 2021 (in Mathison 2021):

This genus includes species formerly placed in Ctenicera and Ludius and more recently under Pseudanostirus . Stropenron columbiana (Brown) is a distinct species from Stropenron propola (LeConte), despite the former originally being described as a subspecies of the latter. These two species are distinct enough to be easily separated and their male genitalia differ; the median lobe apex of the aedeagus is narrower and the apical expansion of the parameres is greater in S. propola as compared to S. columbiana . They also have distinct western and eastern distributions, respectively, in Montana, with overlap occurring only in Fergus Co., a large and ecologically diverse county located in the middle of the state. The genus awaits a formal revision.