Hat Limpet Shell, Lottia mitella

Hat LimpetShell, Lottia mitella. Shell collected off the beach in the greater Los Cabos area, Baja California Sur, July 2019. Size: 2.7 cm (1.1 inches) x 2.1 cm (0.8 inches).

Phylogeny: The Hat Limpet, Lottia mitella (Menke, 1843), is a gastropod mollusk that is a member of the Lottiidae Family of True Limpet Shells. The genus Lottia is one of fifteen genera in this family, and there are sixty-five species in this genus.

Description: Hat Limpet shells have an oval outline and a moderately high profile. The apex is set forward on the shell. The exterior is sculpted with strong radial ribs that extend past the margin in some shells. The exterior of the shell is black with white ribs. The interior is bluish or white, with a central brown strain, and a black and white margin.  Hat Limpets reach a maximum of 2.7 cm (1.1 inches) in length and 2.1 cm (0.8 inches) in height.

Habitat and Distribution: Hat Limpets are found attached to rocks in the intertidal zone, and to depths up to 18 m (60 feet). They are a subtropical to tropical Eastern Pacific species. In Mexican waters they range from Todos Santos, Baja California Sur, to Guatemala, including the Revillagigedo Islands. They are found throughout the Gulf of California.

Ecology and Behavior: Hat Limpets are grazers.  They consume diatoms and algae, which they scrape from the rock with their radula. In turn they are preyed upon by shore birds, crabs, fish and sea stars. They are gonochoric and reproduce sexually, through broadcast spawning.  From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.

Synonyms:  Collisella mitella and Patella navicula.