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 the established phyla. Earlier it was suspected to be closely related to molluscs, but it turned out that the DNA tests was contaminated with DNA from its food, which happened to be molluscs. Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Placozoa (trichoplax) Subregnum Bilateria (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Illustration of the different types of symmetry of Life Forms On Earth. ... Phyla Echinodermata Hemichordata Chordata Chaetognatha (uncertain) Deuterostomes (taxonomic term: Deuterostomia; from the Greek: second mouth) are a superphylum of animals. ... In biology, a species is the basic unit of biodiversity. ... In biology, a genus (plural genera) is a grouping in the classification of living organisms having one or more related and morphologically similar species. ... Illustration of the different types of symmetry of Life Forms On Earth. ... A worm is an elongated soft-bodied invertebrate animal. ... 1949 (MCMXLIX) is a common year starting on Saturday. ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. ... Phyla Echinodermata Hemichordata Chordata Chaetognatha (uncertain) Deuterostomes (taxonomic term: Deuterostomia; from the Greek: second mouth) are a superphylum of animals. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ...

Xenoturbella has a very simple 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. The metre, or meter (symbol: m) is the SI base unit of length. ... The Baltic Sea is located in Northern Europe, from 53 deg. ...

The genus Xenoturbella contains two species:

• Xenoturbella bocki
• Xenoturbella westbladi

References

• 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]