exceptional specimen is a multiple example of Haikouella lanceolata,
thought by its describers to be the earliest craniate-like chordate.
This fish-like animal has many similarities to the contemporaneous
Yunnanozoon lividum, but differs in several aspects: it has a discernible
heart, dorsal and ventral aorta, gill filaments (see the closeup),
and a neural chord. For all these reasons, it was identified by
Chen, Huang, and Li in the seminal Nature paper (Nature 402, 518-522,
02 December 1999) as a chordate.
debate rages on, but whatever the outcome, this creature was much
like the ancestor of all the vertebrates. It derives its generic
name from its resemblance to the modern day lancet Amphioxus.