''Elysia subornata'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of small

sea slug 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 (marine gastropod mollusks) that over evolutionary time ...

, a marine opisthobranch gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Plakobranchidae Plakobranchidae is a family of sea slugs, marine opisthobranch gastropod mollusks in the superfamily Plakobranchoidea. They superficially resemble nudibranchs but they are sacoglossans, members of the clade Sacoglossa within the Opisthobranchia ...

. This sea slug resembles a

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, ...

, but it is not closely related to that order of gastropods. Instead, it is a

sacoglossa Sacoglossa, commonly known as the sacoglossans or the "solar-powered sea slugs", are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia. Sacoglossans live by ingesting the cellular co ...

Description

''Elysia subornata'' grows to a length of about . It is variable in colour, being found in shades of green, olive and beige, sometimes with a reddish tinge. It has broad

parapodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed ...

(fleshy protrusions at the side) with thick white margins sometimes edged in brown or black. The parapodia are covered in tiny papillae (fleshy protuberances) and the

rhinophore A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea ha ...

s (sensory organs on the head) are also papillose.''Elysia subornata''
The Sea Slug Forum. Retrieved 2012-01-22.

Distribution

This species is found in the tropical western Atlantic Ocean, including the Caribbean Sea.

Human uses

It has been proposed that ''Elysia subornata'' could be used as a biological control agent against an invasive strain of the

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

Caulerpa taxifolia ''Caulerpa taxifolia'' is a species of green seaweed, an alga of the genus ''Caulerpa'', native to tropical waters of the Pacific Ocean, Indian Ocean, and Caribbean Sea. The species name ''taxifolia'' arises from the resemblance of its leaf-like ...

'' in the northwestern

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. The high toxicity levels of that alga discourage most of the native herbivorous fauna from consuming it. ''Elysia subornata'', however, preferentially feeds on ''Caulerpa taxifolia'', using the secondary metabolite, Caulerpenyne, for its own defence. It doesn't survive the cool temperature of winter Mediterranean waters, and would therefore need to be raised on a large scale to have any significant effect. Either that; or a hybrid would have to be genetically engineered using DNA from E. timida and/or E. viridis.

References

Plakobranchidae Gastropods described in 1901 {{Placobranchidae-stub