Species · GBIF taxon 2279055
Arrowhead Sand Dollar
Encope microporaAlso known as Pacific Keyhole Urchin, Notched Sand Dollar, Arrowhead Urchin
Arrowhead sand dollars are flat, burrowing echinoderms distinguished by five deep notches along their margins and a single central perforation. They use a carpet of tiny, moving spines to plow through sandy seafloors, filtering organic particles and microscopic algae from the sediment. Their heavy, streamlined tests help them remain anchored in turbulent shallow waters where waves would otherwise sweep them away.
MarineBurrowingBenthic
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & prey
- Diatoms
- Organic detritus
- Microscopic algae
Predators
- Sea stars
- Triggerfish
- Crabs
ThreatsBottom trawling, coastal development, and ocean acidification
HabitatsSandy seafloors, shallow bays, and intertidal zones
Life span8 to 10 years
Size / weightNot available
Classification
- FamilyMellitidae
- SpeciesEncope micropora
Range data is not available yet.
Interaction riskLow
- Low
- Moderate
- High
- Very high
- Why interaction risk is low
- Safe to observe at a normal distance.
Responsible observation
- Check for life: Live individuals are covered in tiny, moving spines and should never be collected.
- Observe burrowing: Place a live individual gently on wet sand to watch it disappear using its spines.
- Handle gently: The rigid skeleton is fragile and can easily crack under pressure.
Predator Close Relative 
Related Family D. Gordon E. Robertson / CC BY-SA 3.0 · cc-by-sa
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