Yunnanozoon
The Yunnanozooan is a suspected chordate or hemichordate from the Lower Cambrian beds of Xiangchiang in Yunnan province, China. Yunnanozoon is similar to the form <Haikouella, which is almost certainly a vertebrate. Still, 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 the Burgess shale of British Columbia in Canada. 13 pairs of symmetrically arranged gonads have been 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).
External linkA picture can be found at http://www.gs-rc.org/repo/repoe.htm
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