| Thordisa bimaculata | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Heterobranchia |
| Order: | Nudibranchia |
| Suborder: | Doridina |
| Superfamily: | Doridoidea |
| Family: | Discodorididae |
| Genus: | Thordisa |
| Species: | T. bimaculata |
| Binomial name | |
| Thordisa bimaculata Lance, 1966 [1] | |
Thordisa bimaculata, commonly known as the two-spotted dorid, is a species of sea slug or nudibranch in the family Discodorididae. [2]
The two-spotted dorid is found in the eastern Pacific Ocean along the coast of California and Baja California; while northwards shifts in its range are associated with warm ocean anomaly events, [3] most observations are concentrated in the Southern California Bight. [4] It inhabits the rocky intertidal zone, up to depths of 33 m. [5] Like many other nudibranchs, the two-spotted dorid is more commonly seen in the summer. [4] [6]
The base color of the two-spotted dorid varies from white, pale yellow, and orange. Both its common and scientific name refer to the two small concentrations of dark brown spots on its mantle: one behind the rhinophores and the other in front of the gills. These patches of spots may be relatively pale or unpronounced depending on the individual, especially if covered by particles of sand or other small debris. The mantle of the two-spotted dorid is covered in long, bulbous, tapering papillae. [5] [6] The dorsal papillae of another dorid in the same genus -- Thordisa verrucosa -- were discovered to excrete an adhesive substance which holds debris in place, perhaps for camouflage; it is likely the dorsal papillae of the two-spotted dorid serve the same function. [6]
The two-spotted dorid is typically 28 mm (1.1 in) in length. This species appears similar to other dorid nudibranchs in body shape: rounded overall with a squat, pointed posterior, retractable gills. The foot is about 2/3 the width of the body. Near its mouth, the two-spotted dorid has two slender, fingerlike tentacles. [6]
Like many other dorids, the two-spotted dorid feeds on sponges. [5]
Like all nudibranchs, the two-spotted dorid is a simultaneous hermaphrodite. While mating, individuals wrestle for dominance, attempting to penetrate and inseminate the other with their penis. The penis of the two-spotted dorid is armored with 7-10 thick, hooked spines in order to aid in this task. Their eggs, or nidosomes, are yellow in color, and, like other sea slugs, are laid in coiled ribbons and attached to a rocky substrate. [6]
Diaulula sandiegensis, commonly known as the San Diego dorid or the ringed dorid, is a species of sea slug or nudibranch, a marine gastropod mollusc in the suborder Doridina and the family Discodorididae.
Doriprismatica sedna is a species of colorful sea slug, a dorid nudibranch, a marine gastropod mollusk in the family Chromodorididae.
Mexichromis trilineata is a colourful species of sea slug, specifically a dorid nudibranch. This marine gastropod mollusc is in the family Chromodorididae. In 2012 the genus Pectenodoris was included into Mexichromis.
Limacia cockerelli is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusc in the family Polyceridae.
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Hopkin's rose nudibranch is a species of sea slug, specifically a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae. Previously known as Okenia rosacea, this species was reclassified as Ceratodoris rosacea in 2024.
Thordisa is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod mollusks in the family Discodorididae.
Chromodoris orientalis is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae. Sea slugs are generally very beautifully colored organisms with intense patterns and ranging in sizes. The Chromodoris orientalis specifically is a white sea slug with black spots in no particular pattern with a yellow, orange, or brown in color ring around its whole body and on its gills. There is much discussion on where it is found, what it eats, how it defends itself without a shell, and its reproduction methods. This is all sought after information because there is not much known about these animals.
Felimare californiensis, common name the California blue dorid, is a species of colourful sea slug or dorid nudibranch, a marine gastropod mollusk in the family Chromodorididae that eats dysideid sponges.
Hypselodoris dollfusi is a species of colourful sea slug or dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae. After being described initially in 1933 by Pruvot-Fol, this species was not seen again until its rediscovery in 2000 in the Sea of Khorfakkan, United Arab Emirates.
Mexichromis antonii is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae.
Mexichromis katalexis is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae.
Mexichromis tura is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae.
Okenia angelensis common name Los Angeles Okenia, is a species of sea slug, specifically a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Okenia liklik is a species of sea slug, specifically a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Okenia mediterranea is a species of sea slug, specifically a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Trapania goslineri is a species of sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Ancula lentiginosa is a species of sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Thordisa rubescens is a species of sea slug, a dorid nudibranch, shell-less marine opisthobranch gastropod molluscs in the family Discodorididae.
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