Xenoturbella
From Freepedia
Xenoturbella is a genus of Bilaterian animals; it is a marine worm. Its taxonomic position has been considered enigmatic since its discovery in 1949, but a 2003 DNA study has positioned it as a primitive deuterostome outside of the established phyla. When treated as a higher-level taxon, Xenoturbella is called Xenoturbellida. Earlier it was suspected to be closely related to molluscs, but it turned out that the DNA tests was "polluted" with DNA from its food, which happens to be molluscs.
Xenoturbella has a very simple body body plan: it has no brain, no gut, no gonads, or any other defined organs; it has cilia and a diffuse nervous system. The animal is up to 4 cm long, and has been found only in the Baltic Sea. Since it lacks gonads, it is a mystery how they reproduce.
Genus Xenoturbella has two species:
Bibliography
- S. J. Bourlat, C. Nielsen, A. E. Lockyer, D. Timothy, J. Littlewood, M. J. Telford (2003). Xenoturbella is a deuterostome that eats molluscs. Nature 424: 925-928. [1]
