Cephalozoa
…region, where they lived during the Ediacaran, approximately 635 to 540 Ma (millions of years ago). Cephalozoa includes the families Yorgiidae and Sprigginidae, as well as genera not assigned to any family: † Archaeaspinus Ivantsov, 2007 (synonym of Archaeaspis) † Archaeaspinus fedonkini Ivantsov, 2001…