Also known as Keyhole Sand Dollar, Five-hole Sand Dollar, Keyhole Urchin
Five-slotted sand dollars glide beneath shallow coastal sands, using thousands of tiny cilia and moveable spines to sift through fine sediment for micro-algae and organic debris. Their distinctive test features five elongated slots called lunules, which help reduce hydrodynamic lift in churning waves and allow sandy currents to pass through smoothly. Feeding actively under the cover of darkness, these flattened echinoderms can manipulate water flow to right themselves whenever strong tides turn them upside down.
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