Black Tegula (Tegula funebralis)
A black tegula with some barnacles living on its shell (photo credit: Lauren Rice)
Description: The black tegula is a beautiful snail with a dark purplish-black shell. Because they make the rocky intertidal zone their home, the black tegula’s shell gets battered by waves and surrounding objects over time, which leads to the tips of its shell getting worn down to the lower pearly-white layer. The shape of the shell is a dome-shaped, round spiraling cone that has four spirals, or “whorls.” These shells tend to reach about 3 centimeters in length. As its name suggests, the actual snail living inside the shell has a black foot and black antennae. The foot of a snail is the flat, squishy part underneath the shell that it uses to cling onto surfaces.
Habitat: Along the Pacific Coast of North America, black tegulas are found as far north as British Columbia and as far south as Mexico. Black tegulas can be found in the tide pools at Haystack Rock living on boulders.
Diet: Black tegulas are grazers that eat soft species of algae found underwater. To eat, these snails use their radula which has many rows of little teeth. The radula is often compared to a tongue—similar to a cat’s tongue—that is used to scrape algae off of rocks and other surfaces.
Tide Pool Tidbits:
It is incredibly important that we never try to rip black tegulas or any other kinds of mollusks off of whatever surface they are clinging onto since this can harm them and leave them more vulnerable to predators.
Oftentimes, hermit crabs will take over abandoned black tegula shells. If you see a black tegula shell with little crab legs sticking out, it’s not a snail!
Male and female black tegulas can be identified by their foot color: males tend to have a paler foot than females do. The foot of a tegula can sometimes be seen sticking out from underneath the shell.
It’s pretty common to find black tegulas that have barnacles and mollusks, such as tiny black limpets or slippersnails, living on their shells. While barnacles and slippersnails stay in one spot, the black limpets will move around and graze on the algae growing on the black tegula’s shell.
Black tegulas can live to be 80-100 years old!
Reference: Central Coast Biodiversity