Triodontella alni is a species of beetle of the family Scarabaeidae. It is found in Italy (Sardinia).
Adults reach a length of about 5âÂÂ7 mm. They have a brownish-black, rather shiny body. The antennae and legs are reddish-brown. The sides of the pronotum are lightened, as is the base, in front of the scutellum (the latter is also testaceous). The elytra are brownish-black.