Common Heart Urchin, Sea Potato
Phylum: Echinodermata, Class: Echinoidea, Order: Spatangoida, Family: Loveniidae, Genus: Echinocardium, Species: E. cordatum · Loveniidae (Heart Urchins) · Echinoderm Test (Irregular Sea Urchin). Classification: Non-mollusk shell. Shape: Heart-shaped or ovoid with a distinct anterior indentation.
Species
Echinocardium cordatum
Shell Type
Echinoderm Test (Irregular Sea Urchin). Classification: Non-mollusk shell. Shape: Heart-shaped or ovoid with a distinct anterior indentation.
Family
Loveniidae (Heart Urchins)
Size
Approximately 3-5 cm in length. This is a standard size for a mature adult; the species typically ranges from 2 to 9 cm.
Color & Pattern
Naturally dull white to creamy yellow when dry and cleaned. When alive, it lacks colorful patterns and is covered in fine, hair-like yellowish-brown spines. The 'test' (shell) shows a star-shaped pattern of pore pairs on the dorsal surface.
Rarity
Common. These tests are frequently found on British beaches after storms or high tides, though they are very fragile.
Habitat
Burrows in sand or muddy sand at depths from the lower intertidal zone down to 200 meters. Marine environment.
Geographic Range
Cosmopolitan distribution; extremely common in the North Sea and around the coasts of the British Isles, including Troon, Scotland.
Description
An 'irregular' sea urchin test characterized by a globular, heart-like shape. The surface is covered in tiny tubercles where spines were once attached. Five indented 'petals' (ambulacra) represent where tube feet emerged. It is light, hollow, and delicate.
Key Features
Distinctive heart-shaped indentation at the front (anterior); asymmetric shape; fine, sandpaper-like texture; lack of large spine sockets compared to regular urchins.
Collector Value
Minimal monetary value, but high sentimental and educational value for beachcombers. Its fragility makes perfectly intact specimens desirable for local displays.
Condition Notes
Fair to Good. The specimen is intact which is notable for this species as they are exceptionally thin-walled and often break in the surf. It appears sun-bleached and weathered with minor sand debris in the pores.
Interesting Facts
Known as 'Sea Potatoes' due to their shape. When alive, they live 10-15 cm deep in the sand and maintain a 'chimney' to the surface for breathing and feeding using specialized tube feet.
Ecological Role
Important bioturbator; it 'ploughs' through the sand, oxygenating the sediment and recycling nutrients. It is a prey source for various fish and sea birds.
Similar Species
Echinocardium flavescens (Yellow Sea Urchin), which has a more rounded anterior and lacks the deep frontal groove.
Beach Finding Tips
Look along the strandline (the high tide mark) after a period of onshore winds or heavy storms. They are light and often blow into the dunes or get trapped in sea foam.
Notes
Troon Scotland