Common Heart Urchin, Sea Potato
Phylum: Echinodermata; Class: Echinoidea; Order: Spatangoida; Family: Loveniidae; Genus: Echinocardium; Species: E. cordatum · Loveniidae (Heart urchins/Sea potatoes) · Echinoid (Sea Urchin test/skeleton). Heart-shaped, irregular urchin test.
Species
Echinocardium cordatum
Shell Type
Echinoid (Sea Urchin test/skeleton). Heart-shaped, irregular urchin test.
Family
Loveniidae (Heart urchins/Sea potatoes)
Size
Approximately 3-4 cm in length; typical adult range for this species is 3-9 cm.
Color & Pattern
Off-white to light cream base color. The surface is covered in fine, granulated tubercles where spines once attached. It lacks distinct color patterns, appearing naturally sun-bleached and weathered as is common for beach-cast tests.
Rarity
Very Common. Found regularly on sandy beaches after storms or high tides.
Habitat
Burrows in fine to medium sand from the lower shore/intertidal zone down to depths of 200 meters. Marine environment.
Geographic Range
Cosmopolitan distribution; found in all oceans. Extremely common around the British Isles, including Troon, Scotland, and the North Sea.
Description
A delicate, heart-shaped skeleton (test) characterized by a visible indentation at the front end, giving it a tuberous or potato-like appearance. The surface is adorned with thousands of tiny bumps (tubercles) and five petal-like grooves (ambulacra) on the upper surface for tube foot extension.
Key Features
Heart-shaped apical profile; deep anterior groove; four distinct 'petals' on the top; exceptionally thin and fragile shell structure compared to regular sea urchins.
Collector Value
Low monetary value ($1-$5) due to high abundance, but highly desired by beachcombers for their fragile beauty and unique 'heart' geometry. Specimens are difficult to transport without breaking.
Condition Notes
Fair to Good. The test is mostly intact but shows signs of beach wear with small holes and salt erosion. The original hair-like spines are completely missing, which is standard for beach-found specimens. Collectibility grade: Fair.
Interesting Facts
The living animal is covered in yellow, hair-like spines and lives buried up to 15cm deep in the sand. They use specialized tube feet to create a respiratory funnel to the surface. In the UK, they are nicknamed 'Sea Potatoes' due to their shape and color when first washed up.
Ecological Role
Important detritivore and 'bioturbator.' By burrowing and feeding on organic matter in the sand, they oxygenate the sediment and prevent it from becoming anaerobic. They are a prey source for various fish and sea birds.
Similar Species
Echinocardium flavescens (Yellow Sea Urchin), which has a more oval shape and less pronounced frontal groove.
Beach Finding Tips
Look along the strandline on sandy Scottish beaches like Troon after a westerly gale. They are often found trapped among seaweed or in hollows left by the receding tide.
Notes
Troon Scotland