Cyrtepistomus castaneus is a small insect belonging to the family Curculionidae, commonly known as weevils. It is characterized by its chestnut-brown coloration, which gives it its specific epithet "castaneus." This weevil species is typically found in forested areas, where it feeds on the leaves and stems of various plants. Its distinctive long snout and elbowed antennae are adaptations for feeding and locating suitable host plants.