Whilst named after the Ediacaran organismSpriggina, later work has shown the two to be unrelated. Evidence for cranial structures is present in one of the specimens. Metaspriggina is considered to represent a primitive chordate, possibly transitional between cephalochordates and the earliest vertebrates. It lacked fins and eyes, but had a poorly developed cranium. The largest specimens were 7 millimetres (0.28 in) in length. It was likely free-swimming but occasionally found on the sea floor.
^ abcConway Morris, Simon (2008). "A Redescription of a Rare Chordate, Metaspriggina walcotti Simonetta and Insom, from the Burgess Shale (Middle Cambrian), British Columbia, Canada". Journal of Paleontology82 (2): 424. doi:10.1666/06-130.1.
^SMITH, M. P., I. J. SANSOM AND K. D. COCHRANE. 2001. The Cambrian origin of vertebrates, p. 67-84. In P. E. Ahlberg (ed.), Major Events in Early Vertebrate Evolution: Palaeontology, Phylogeny, Genetics and Development. Taylor and Francis, London.