Paracentrotus lividus is a species of sea urchin in the family Parechinidae, commonly known as the purple sea urchin. It is a marine echinoderm native to the northeastern Atlantic Ocean and the Mediterranean Sea, ranging from the coasts of Scotland and Ireland southward to Morocco, and throughout the Mediterranean basin. The genus name Paracentrotus derives from the Greek para- meaning “beside” or “near” and kentron meaning “spine” or “sharp point,” indicating its close relation to other spiny sea urchins in the genus Centrostephanus and related taxa, while the species epithet lividus comes from Latin meaning “bluish” or “lead-colored,” referring to its characteristic dark purple to violet coloration.

Historically, Paracentrotus lividus has been harvested since antiquity in Mediterranean coastal communities, with evidence of sea urchin consumption in ancient Greek and Roman contexts. As a food source, Paracentrotus lividus produces edible gonads known as roe or uni, which are consumed raw, lightly dressed with olive oil and lemon, spread on bread, or incorporated into pasta and seafood dishes in Mediterranean cuisines. It is particularly associated with southern Italian, Sardinian, Sicilian, Catalan, and Provençal food traditions.

The species contains omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which contribute anti-inflammatory and cardioprotective effects; echinochrome A, a polyhydroxylated naphthoquinone pigment with antioxidant activity; ovothiol, a sulfur-containing antioxidant molecule found in marine invertebrate eggs and gonads; and carotenoids such as β-carotene and astaxanthin, which contribute to pigmentation and possess antioxidant properties. These compounds contribute to both the nutritional value and the distinctive flavor profile of the roe, which is prized for its briny sweetness and creamy texture.