Primitive vertebrates,Haikouella lanceolata,artwork. H. lanceolata is an extinct,soft-bodied life-form,discovered in Lower Cambrian (520 million-year-old) deposits in Yunnan Province,China. It is thought to be a precursor to modern day vertebrates as fossils show early versions of features typically found in true vertebrates such as fishes. These include a spinal cord,internal organs,brain,gills,eyes,muscle blocks known as myomeres and a true tail. However,H. lanceolata does not have bones or a moveable jaw. Its spinal cord is protected by stiff tissue known as a notocord. H. lanceolata represents the evolutionary transition from invertebrates to vertebrates |