Platychelus expansus is a species of beetle of the family Scarabaeidae. It is found in South Africa (Northern Cape).
Adults reach a length of about . They are black, with a dark green metallic tinge on the pronotum. The head and pronotum are clothed with a fulvous erect, somewhat villose pubescence. The scutellum, propygidium, and pygidium are clothed with dense appressed fulvous hairs and the elytra are very closely punctured, and covered with a very short, erect black pubescence.