Alderia willowi is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sea slug

Slug

Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...

, a marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusk in the family Limapontiidae. It is a sacoglossa

Sacoglossa

Sacoglossa, commonly known as the sacoglossans or the "sap-sucking sea slugs", are a clade of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia...

n.

This species is endemic to California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It was previously thought to be Alderi modesta, but there turned out to be a cryptic species pair.

This species is poecilogonous, in other words it has variable larval development modes.

The slug was discovered by a team led by Patrick Krug of California State University, Los Angeles

California State University, Los Angeles

California State University, Los Angeles is a public comprehensive university, part of the California State University system...

. The species is named after Krug's grandmother, and after the fictional character

Fictional character

A character is the representation of a person in a narrative work of art . Derived from the ancient Greek word kharaktêr , the earliest use in English, in this sense, dates from the Restoration, although it became widely used after its appearance in Tom Jones in 1749. From this, the sense of...

 Willow Rosenberg

Willow Rosenberg

Willow Rosenberg is a fictional character created for the fantasy television series Buffy the Vampire Slayer . She was developed by Joss Whedon and portrayed throughout the TV series by Alyson Hannigan...

 from Buffy the Vampire Slayer television series.