Fissurellinae

Fissurellinae is a subfamily of small to medium-sized marine gastropods belonging to the family Fissurellidae, commonly known as keyhole limpets or keyhole limpets. These mollusks are characterized by their distinctive, often irregularly shaped shells, which typically feature a keyhole-like opening. The subfamily is widely distributed across the world's oceans, inhabiting intertidal and shallow subtidal rocky shores.

Members of Fissurellinae are primarily herbivorous, feeding on algae and other organic material scraped from surfaces using their radula. Their shells vary in color, often blending with the surrounding environment, and can exhibit patterns ranging from smooth and uniform to highly textured and intricate. Some species display vibrant hues, including shades of red, orange, yellow, and brown, while others remain more subdued in appearance.

The taxonomy of Fissurellinae includes several genera, such as *Fissurella*, *Diodora*, *Scissurella*, and *Cryptofissurella*, among others. *Fissurella* is one of the most well-known genera, with species like *Fissurella nigra* (the black keyhole limpet) being particularly recognizable. These limpets are ecologically significant, as they play a role in controlling algal growth and contributing to the health of rocky intertidal ecosystems.

Fissurellinae limpets are generally small, with shells typically measuring a few centimeters in length. They are sessile creatures, attaching themselves to rocks or other substrates using a strong, muscular foot. Their movement is limited, and they primarily remain in one location, though they may shift slightly to access new food sources. Some species exhibit sexual dimorphism, with males and females displaying slight differences in shell morphology.

Due to their ecological niche and aesthetic appeal, certain species of Fissurellinae are collected by marine enthusiasts and hobbyists. However, overcollection and habitat destruction pose threats to some populations, emphasizing the importance of sustainable practices in their conservation.