Adults about 12-15 mm long, oval in shape and shiny black. Males have a thickened tarsus on each foreleg.
Heteronychus arator can be distinguished from A. coulonii as follow:
In dorsal view, H. arator body shape is almost parallel compared to distinctly oval in A. coulonii.
Elytra of H. arator is weakly impressed with longitudinal striae and indistinctly punctate between striae compared to A. coulonii elytra which has deeply impressed striae and distinctly punctate between striae.