17 facts about the wee sea potatoes

In honor of St. Patrick’s Day, and my Irish heritage, here’s a post on the humble and charming sea potato.

1. The dried shell (also known as the test) of this urchin resembles a potato, hence the common name – sea potato.
2. The sea potato, Echinocardium cordatum, is a common echinoderm found along beaches on all coasts of Britain and Ireland.
3. The sea potato is related to sea urchins, heart urchins, and sand dollars.
4. Most sea urchins live in rocky areas, but the sea potato prefers sand, particularly muddy sand.
5. The spines of this echinoderm are thin and flattened.
6. On the underside of the urchin are special spoon-shaped spines that help it to dig.
7. There are longer spines of the back of the sea potato which aid in helping to breathe while it is burrowing.
8. The sea potato can survive to depths of 650 feet.
9. Unlike regular urchins, the sea potato has a distinct front end (i.e., not circular).
10. The sea potato can grow up to 3 inches.
11. The sea potato is very fragile and rarely survives collection.
12. While alive the sea potato is deep yellow in color and covered in fine spines.
13. The sea potato prefers sub-tidal regions in temperate seas.
14. The sea potato are a type of heart-shaped urchin.
15. Sea potato are deposit feeders and tube feet on its underside the sea urchin pick up sediment from the front of its mouth.
16. The sea potato has no conservation concerns.
17. The sea potato often has a commensal symbiotic relationship with the bivalve Tellimya feringuosa attached to its anal spines.

A sea potato, commonly found along the shore of Ireland

The test of the sea potato

The underside of the sea potato