High Quality Content by WIKIPEDIA articles! Xenoturbella is a genus of bilaterian animals; it contains two marine worm-like species. The first known species (Xenoturbella bocki) was discovered in 1915 by Sixten Bock but the first published description was only in 1949 by Einar Westblad. Its taxonomic position has been considered enigmatic since its discovery but a 2003 DNA study has positioned it as a primitive deuterostome outside the established phyla (Bourlat et al., 2003). Earlier it was suspected to be closely related to molluscs (Noren Jondelius, 1997), but it turned out that the DNA test was contaminated with DNA from molluscs which it may have eaten (Bourlat et al., 2003; Israelsson Budd, 2006). The earlier results were recently corroborated; the genus is now the sole member of its own phylum Xenoturbellida (Haszprunar et al., 1991; Bourlat et al., 2006). It appears that this phylum is basal within the deuterostomes, and allied with the acoelomorpha, forming a sister clade to the echinoderms and hemichordates.