Noble pen shell

Photo: francesco_massidda · CC BY-NC

Noble pen shells are filter feeders that draw large volumes of water through their gills to extract phytoplankton and suspended particles, contributing meaningfully to local water clarity. They host a commensal shrimp (Pontonia pinnophylax) and small crab (Pinnotheres pisum) living inside the mantle cavity in a non-parasitic relationship. The species is now the subject of urgent conservation breeding and genetic preservation programmes across Spain, Italy, and Croatia.