Cathaymyrus is a genus of Early Cambrian chordate known from the Chengjiang biota in Yunnan Province, China. Both species have a long segmented body with no distinctive head. The segments resemble v-shaped muscle blocks found in cephalochordates such as Amphioxus. A long linear impression runs along the "back" of the body looking something like a chordate notochord.^{[citation needed]}

While some authors have suggested that the genus is a cephalochordate and closely related to living lancelets, other authors have disputed this due to the poor preservation of the head region, considering its placement within Chordata uncertain.