How did *Wiwaxia*'s protective plates differ fundamentally from those found on early arthropods like *Marrella*?

*Wiwaxia*'s plates were simpler and distributed over a single, continuous soft body form.

While both *Wiwaxia* and organisms like *Marrella* utilized external plates (sclerites) for protection, the underlying body architecture differed significantly. *Marrella*, being an early arthropod, featured plates that were part of a more complex, segmented system characteristic of that phylum. In contrast, the sclerites of *Wiwaxia* were described as being simpler and distributed more randomly or continuously across its single, continuous soft body form. This difference highlights that convergent evolution resulted in armored surfaces in the Cambrian, but *Wiwaxia* achieved this protection via a body plan distinctly separate from the emerging dominant arthropod blueprints.