Purple Topshell

Steromphala umbilicalis

Steromphala umbilicalis, commonly known as the Purple Topshell, is a small marine gastropod with a shell size ranging from 10 mm to 22 mm. Its shell is more depressed compared to Gibbula cineraria, featuring sharper and fewer spiral ridges, particularly in younger specimens. The shell displays distinctive red longitudinal streaks that are broader and less numerous than those of similar species. The outer lip of the shell is bordered by two colors: yellow and green, which are variegated with red spots and have a minutely tubercled texture. This species inhabits European waters and the Mediterranean Sea off Morocco, residing on sheltered rocky shores from the upper shore down to the sublittoral zone. Steromphala umbilicalis is tolerant of emersion and can thrive in brackish waters. It is typically found at depths shallower than 40 meters, with 90% of recorded occurrences at depths less than 30 meters. As a herbivorous species, the Purple Topshell grazes on algae and organic matter found on the rocky substrates where it resides. Breeding habits are not detailed in the sources, but encounters with this species during dives can be common. The conservation status of Steromphala umbilicalis is not evaluated in the sources.