Amphioxus

     The creature amphioxus, also known as a lancelet, is a member of Phylum Chordata and is important to the evolutionary view of the development of vertebrates. It lives in the sands of shallow, temperate to tropical waters where it feeds on material in the water. Amphioxus is seen to be the most basic animal that possesses a nerve cord along the length of their back, a defining feature for vertebrates. They also have the same muscle grouping as vertebrates. However, the amphioxus has no true skeleton, brain, or comparable sensory organs; even though it has gills, they are not used for breathing at all but rather for eating (breathing is done through the skin). Though this small, semi-transparent creature also has many characteristics not common to other vertebrates (like its simpler notochord), current genetic work seems to show that the common ancestor of all chordates had a genetic code very similar to that of amphioxus. A labeled figure of amphioxus can be seen below.