Ptinus fur, the whitemarked spider beetle, is a species of spider beetle in the genus Ptinus (family Anobiidae), with a nearly cosmopolitan distribution. Adults are red-brown with yellow hairs, and 2.0–4.3 millimetres (0.08–0.17 in) long. The prothorax is densely covered with pale hairs, while the elytra bear some patches of white scales. It is a pest of stored foods.