Ptinus fur, the white marked spider beetle, is a species of spider beetle in the genus Ptinus (family Ptinidae), with a nearly cosmopolitan distribution.

[2] It is red-brown with yellow hairs, and measures 2.0–4.3 millimetres (0.08–0.17 in) in length.

The prothorax is densely covered with pale hairs, while the elytra bear some patches of white scales.

[2] Ptinus fur adults feed on dried and decaying animal and vegetable material.

[5] Well-defined diapause as mature larvae in cocoons occurs at low temperatures in some individuals of Ptinus fur: at 23 °C this lasts about 220 days after normal larvae have pupated; at 20 °C the period lasts about 280 days.