The fossil record of siliceous sponge spicules can be taken at face value
Sandy Cui, Nicole Mizrahi, Shaily Rahman, Scott Nichols, Talia S. Karim, Carl Simpson
The paper shows that siliceous sponge spicules first appear in the fossil record during the Cambrian, not the Ediacaran, and that this reflects their actual evolutionary timing rather than taphonomic bias.
bioRxiv · Jan 30, 2026 · PreprintPaleontology