Laevapex fuscus, the dusky ancylid, is a species of small, freshwater, air-breathing limpet, an aquatic pulmonate gastropod mollusc or micromollusc in the family Planorbidae, the ram's horn snails and their allies.

[4] Simple annual (univoltine) and two-generation per year (bivoltine) life cycles have been reported in New York populations of L.

[8] The bioenergetic data collected for the species suggest that its reproductive effort is in line with expectation from adult weight, and hence that its life history strategy is undifferentiated.

[10] L. fuscus has been observed attached to the wings or hemelytra of the water bug species Belostoma flumineum (Hemiptera: Belostomatidae).

This observation suggests that belostomatids might serve as a mode of transport and a passive dispersal agent for L. fuscus and other ancylid species.