Rough Limpet

Lottia scabra

Lottia scabra is a marine gastropod that typically grows to a length between 19 and 40 millimetres. Its shell is characterized by rugged radial ribs with darker interspaces and a scalloped margin. The shell color ranges from mottled grey to tan, while the head and foot exhibit white with black spots. It is commonly found along the Pacific coast of North America, from Cape Arago in Oregon to southern Baja California, inhabiting horizontal rock surfaces in the higher littoral zone. This species prefers both exposed and protected coastlines and can be found at low tide, where it often settles in a specific location that matches the contours of its shell to the rock surface beneath it. L. scabra primarily feeds on microscopic algae and diatoms, using its radula to rasp them off rock surfaces. It has a unique ability to grind a groove into the rock with its scalloped shell edge, allowing it to fit snugly into its home base, which helps it survive in desiccating conditions. This limpet is known to coexist with Lottia digitalis, but each species occupies different habitats, with L. scabra favoring horizontal surfaces. Breeding occurs through a gonochoric reproductive strategy, with embryos developing into planktonic larvae before maturing into adults. Encounters with L. scabra during a dive may reveal them clinging to rocks, often in groups, especially in their preferred habitats. The conservation status of L. scabra is not evaluated, but it is commonly found at numerous dive sites.