- This univalve bonds tightly to the shell and rarely moves; over time, the crab ends up with a stack of many generations of slipper shells.
- Thus, all rostroconches and some helcionellacean univalves technically become stem group bivalves.
- But who speaks out for the univalve and the bivalve?
- Now explain how a univalve differs from a bivalve, in more ways than just the number of shells.
- In the earliest Cambrian, one lineage developed a bivalved mineralized shell (Fordilla and its relatives), the other an endogastric univalve shell (the Helcionellids).
- Vetustovermis bears a number of morphological features that are found in Kimberella, which has been interpreted to have a non-mineralized but stiff univalve shell.