A Case Of Mistaken Identity...

"That in turn can teach us more about the Cambrian explosion: that these algae quite possibly played a more significant role than previously thought in the rapidly increased biodiversity that happened around that time."

The mysterious case of the missing Bryozoan fossils has apparently once again been opened. Why is this class of creature the only one not to feature in one of the most sudden bursts of life in the history of organisms?

One answer might be that we just haven't found the right clues yet. It's possible that the earliest forms of Bryozoans had softer parts, which means they wouldn't have left behind fossils in the first stages of their evolution.

https://www.sciencealert.com/weird-lifeform-from-500-million-years-ago-wasnt-an-animal-at-all