Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails that, over evolutionary time, have either entirely lost their shells or have seemingly lost their shells due to having a significantly reduced or internal shell. The name "sea slug" is often applied to nudibranchs and a paraphyletic set of other marine gastropods without apparent shells.
Sacoglossa are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia known as sacoglossans. There are 284 valid species recognized within this superorder. Sacoglossans live by ingesting the cellular contents of algae, hence they are sometimes called "sap-sucking sea slugs". Some sacoglossans simply digest the fluid which they suck from the algae, but in some other species, the slugs sequester and use within their own tissues living chloroplasts from the algae they eat, a very unusual phenomenon known as kleptoplasty, for the "stolen" plastids. This earns them the title of the "solar-powered sea slugs", and makes them unique among metazoan organisms, for otherwise kleptoplasty is known only among single-celled protists.
Limapontiidae is a taxonomic family of small to minute sacoglossan sea slugs. These are marine opisthobranch gastropod mollusks.
Placida dendritica is a species of minute sea slug, a marine opisthobranch gastropod mollusk or micromollusk in the family Limapontiidae.
Elysia crispata, common name the lettuce sea slug or lettuce slug, is a large and colorful species of sea slug, a marine gastropod mollusk.
Elysia timida is a species of sacoglossan sea slug, a marine opisthobranch gastropod mollusk. Found in the Mediterranean and nearby parts of the Atlantic, it is herbivorous, feeding on various algae in shallow water.
Elysia pusilla is a species of small sea slug, a marine gastropod mollusk in the family Plakobranchidae. It is a sacoglossan.
Elysia maoria is a species of marine gastropod mollusk in the family Plankobranchidae. It is found off of New Zealand.
Kikutaro Baba was a Japanese malacologist. He was the leading researcher on sea slugs and bubble snails, opisthobranch gastropod mollusks in Japan.
Cyerce kikutarobabai is a species of sacoglossan sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Caliphyllidae.
Polybranchia is a genus of sacoglossan sea slugs, shell-less marine opisthobranch gastropod mollusks in the family Hermaeidae.
Ercolania kencolesi is a species of sacoglossan sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Limapontiidae.
Ercolania is a genus of small sacoglossan sea slugs, shell-less marine opisthobranch gastropod mollusks in the family Limapontiidae.
Ercolania tentaculata is a species of sacoglossan sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Limapontiidae. It is estuarine.
Ercolania varians is a species of sacoglossan sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Limapontiidae.
Ercolania zanzibarica is a species of sacoglossan sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Limapontiidae.
Oxynoe azuropunctata is a species of small sea snail or sea slug, a bubble snail, a marine gastropod mollusk in the family Oxynoidae.
Aplysiopsis is a genus of sacoglossan sea slugs, a shell-less marine opisthobranch gastropod mollusks in the family Hermaeidae.
Costasiella ocellifera is a small (5–13 mm) species of sea slug, a shell-less marine gastropod mollusk in the family Costasiellidae. Costasiella ocellifera, and other members of the Costasiellidae family are often mistakenly classified as nudibranchs because they superficially resemble other species of that group, but they are actually a part of the Sacoglossa superorder of sea slugs, also known as the “sap-sucking sea slugs,” "crawling leaves" or the "solar-powered sea slugs." C. ocellifera was discovered by Simroth in 1895, and was initially classified as Doto ocellifera. The Brazilian species, Costasiella liliana, is a synonym of C. ocellifera.Costasiella ocellifera shows long-term retention of functional kleptoplasty.
Costasiella nonatoi is a species of sacoglossan sea slug in the genus Costasiella. It is one of few species in the genus that is not photosynthetic. The description of this species was based on two specimens which were serially sectioned and designated as the holotype. The species was named after Dr. Edmundo Nonato, a professor at the Oceanographic Institute of the University of São Paulo.
