This is the Spiny Cockle (Acanthocardia aculeata), a sturdy, oval-shaped bivalve with a heart-shaped profile. Its shell typically measures between 5 and 11.5 cm in length and has up to 22 raised ribs, each lined with sharp spines. Concentric rings appear between the ribs, and the inside is smooth and white with distinct grooves running through the valves.

Location:
Mediterranean Sea and Northeast Atlantic, living in muddy sand.

Average Size:
5–11.5 cm in length.

Family:
Cardiidae (Cockles)

Species:
Acanthocardia aculeata

Ecological Role:
The Spiny Cockle plays an important role in its habitat by filtering water and contributing to sediment turnover, helping to maintain the health of coastal ecosystems.

Reproduction:
Spiny Cockles reproduce by releasing eggs and sperm into the water, where fertilisation occurs externally.

Conservation Status:
Not considered threatened, though monitoring is important due to habitat changes from coastal development and pollution.