Thordisa bimaculata
Thordisa bimaculata, commonly known as the two-spotted dorid, is a small sea slug in the family Discodorididae.
Distribution and habitat: It lives along the eastern Pacific coast, from Baja California to California, mainly in the Southern California Bight. It inhabits rocky shores from the intertidal zone down to about 33 meters and is typically seen in summer.
Description: The animal is about 28 mm long. Its color ranges from white to pale yellow or orange. It has two dark brown spots on its mantle—one behind the rhinophores and one in front of the gills. The mantle is covered with long, bulbous papillae. Near its mouth are two slender tentacles.
Diet: It feeds on sponges.
Reproduction: Like other nudibranchs, it is a simultaneous hermaphrodite. During mating, individuals wrestle to impregnate each other with a penis that has 7–10 hooked spines. Eggs are yellow and laid as coiled ribbons (nidosomes) on rocks.
Taxonomy: Binomial name Thordisa bimaculata. Described by Lance in 1966. Kingdom Animalia; Phylum Mollusca; Class Gastropoda; Order Nudibranchia; Family Discodorididae; Genus Thordisa; Species bimaculata.
This page was last edited on 1 February 2026, at 22:16 (CET).