Noble pen shell

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.