It is similar to the form Haikouella which is almost certainly a vertebrate. There are anatomical differences from Haikouella including a smaller stomach, and much larger (1mm) pharyngeal teeth. Yunannozoon is not known for sure to possess many features like heart, gills, etc. that are known from well preserved specimens of Haikouella. Yunnanozoon somewhat resembles the Middle Cambrian Pikaia from British Columbia's Burgess shale. 13 pairs of symmetrically arranged gonads are identified as are possible gill slits.. However, some authors think that Yunnanozoon is closely related to the chordate Haikouella and that Yunnanozoon is probably a chordate rather than a hemichordate.
There is one species Yunnanozoon lividum (Chen et al., 1995).
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