“Annelids are very rare in the Cambrian of North America, and so far we only knew of a single specimen from the Spence Shale,” said lead author Julien Kimmig, a paleontologist with the State Museum of Natural History in Karlsruhe, Germany. “The new annelid Shaihuludia shurikeni is especially interesting, as it had some very impressive chaetae, which makes it unique among the Cambrian annelids. The way that the fossil is preserved is also of particular interest, because most of the soft tissue is preserved as an iron oxide ‘blob,’ suggesting the animal died and was decomposing for a while before it was fossilized. However, with the analytical methods used in the paper, we show that even with limited preservation you can identify fossils.”

In the process, the team reexamined a fossilized annelid previously found in the Spence Shale and reclassified it as Burgessochaeta — a surprise because until then, Burgessochaeta have only been found in another famed fossil deposit in British Columbia, Canada.