An Early Cambrian Hemichordate Zooid

An Early Cambrian Hemichordate Zooid: "Xian-guang Hou, Richard J. Aldridge, David J. Siveter, Derek J. Siveter, Mark Williams, Jan Zalasiewicz, Xiao-ya Ma. Hemichordates are known as fossils from at least the earliest mid-Cambrian Period (ca. 510 Ma) and are well represented in the fossil record by the graptolithinid pterobranchs (“graptolites”), whi...."