Definition
cystoids
noun
- Plural of cystoid; extinct marine animals of the class Cystoidea, related to starfish and sea urchins, characterized by a cup-shaped or sac-like body with arms or brachioles.
Usage: paleontology; technical
Examples
- Cystoids were common in ancient seas during the Paleozoic era.
- Paleontologists discovered several well-preserved cystoid fossils in the limestone deposits.
- Unlike crinoids, cystoids had a more compact, globular body structure.
- The cystoids represent an important branch in the evolutionary history of echinoderms.