How does metamorphosis change an echinoderm larva into a five-rayed juvenile?

During the process of metamorphosis, an echinoderm larva undergoes a complex transformation that shifts its body plan from a fundamental bilateral symmetry to a radial one.1

This transition is primarily driven by the development of the water-vascular system, which organizes into five distinct canals. This pentamerous (five-rayed) arrangement becomes the dominant structural pattern for the juvenile, effectively overshadowing the larva's original bilateral symmetry. While the specific timing and location of this change vary by group—with some species metamorphosing while floating in the plankton and others attaching to the seafloor first—the resulting juvenile consistently exhibits this characteristic radial structure in its major organ systems, skeleton, and tube feet.12