Pentasters

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Pentasters are a rare group of dinoflagellates with an internal skeleton. The best-known member is Actiniscus pentasterias, which has two silica-based, five-armed star shapes around the nucleus. Ehrenberg described the species, noting that the living cell is colorless and does not move, and he drew the skeletal elements (pentasters) from fossils found in rocks around the world. These pentasters are preserved as microfossils. Studies have included Cenozoic samples from the South Pacific, and Tappan’s survey of dinoflagellates with internal skeletons provided the first detailed description of pentasters using scanning electron microscopy. The ultrastructure of Actiniscus pentasterias has also been investigated.