The Asteroidea (also known as sea stars or starfish) are among the most diverse and familiar of the living Echinodermata, including over 1800 species from every ocean basin in the world, including the Atlantic, Indian, and Pacific as well as the Arctic and the Southern Ocean, inhabiting intertidal to 6000 m abyssal settings. Living asteroids are pentagonal to stellate (although some sphaerical forms are known) and have arms that are continuous with the disk. Two to four rows of tube feet are present. Most asteroids have five rays, but some can have as many as 50.

Taxonomic coverage of the database includes not only all “true” starfish taxa but also the enigmatic and controversial concentricycloids, which have been included based on the taxonomic classification of Mah (2006). Although identification of taxa with fossil members is indicated, most have not yet been included. Some fossil taxa may be entered in the future for completeness but fossil groups were not a primary objective for the WoRMS database.

The core of the World Asteroidea Database (WAD) is derived from the "Asteroid Names List" developed primarily by Ailsa M. Clark. However the WAD is complimented by numerous other echinoderm compendia (e.g., Clark & Downey's Starfishes of the Atlantic, Rowe & Gate's Zoological Catalogue of Australia, etc) and will eventually include all subsequent taxonomic changes and newly described taxa.

Please inform the editor, Christopher Mah, of any omissions, typos, or errors you encounter. I am also happy to review and discuss, other issues, such as synonymies, controversial taxonomic assignments, or broader classification questions and to initiate changes if they are warranted. All inquiries and discussion will be evaluated promptly but critically, and if deemed reasonable, included quickly into the database.

Further information on asteroids and echinoderms may be found at the authors’ blog: echinoblog.blogspot.com. An academic profile of the authors can be found at: http://invertebrates.si.edu/mah.htm.