Asteroidea (five species) and Ophiuroidea (18 species) recorded along the Uruguayan littoral (up to 50 m depth) are summarized and their distributional pattern are discussed. Species are gathered into four groups: 1) A. taxa distributed from North/South Carolina, or from the Caribbean Sea, to Southern Buenos Aires Province (Argentina), B. species ranging from North/South Carolina, Florida, São Paulo, to the mouth of Rio de la Plata, 2) species ranging from Rio de Janeiro south to the San Matias Gulf, 3) taxa recorded from Chile or from Antarctic/Subantarctic waters north to Uruguay, 4) a single cosmopolitan species. While ophiuroids are represented in each one of the mentioned groups, asteroids are restricted to the first one. As it happens with other elements of the Uruguayan fauna, this complex pattern is a consequence of the confluence of the warm Brazilian and the cold Malvinas (Falkland) currents, and of the discharge of fresh, muddy waters of the Rio de la Plata. Rev. Biol. Trop. 56 (Suppl. 3): 205-214. Epub 2009 January 05.
Keywords: Asteroidea, Ophiuroidea, Uruguay, Rio de la Plata, biogeography, distribution