This document reports on the discovery of a new species of lamellated pen shell, Atrina lamellata, off the coast of Thoothukudi, India. A single specimen was collected from a depth of 310 meters and identified based on its morphological characteristics. This extends the known distribution of A. lamellata to include the southeast coast of India. Little is known about pen shell populations in this region. This study provides a first documentation and taxonomic identification of A. lamellata in the waters off Thoothukudi.