About Heteronychus arator (Fabricius, 1775)
This species is the black beetle Heteronychus arator, a scarab beetle with the following morphological characteristics. Adults are shiny black, or occasionally dark reddish brown, oval-shaped beetles ranging from 12 to 15 millimeters in length. Unlike many other scarab species, the head of Heteronychus arator has no carina or tubercles. Its clypeus is cut off straight at the end, has clear distinct lateral margins, is toothed along its front edge, and bears one small additional tooth in the center of the edge. Each mandible has 2 to 3 teeth along its outer edge, and the mandibles are fully visible when viewing the beetle from above. Antennae are 10-segmented, and end in a club made of 3 distinct segments. On the underside of the head, the mentum has a rounded tip. Each eye is partially divided by a smooth, hairless ocular canthus. The pronotum is smooth, convex in shape, and lacks any punctures. The elytra bear rows of shallow striae. The propygidium, the dorsal plate of the second-last abdominal segment, has a pair of stridulatory bands. The tibiae of the hind legs have straight, truncated ends. All legs end in simple, unmodified tarsal claws.
