Occurrence, taxonomic notes and morphometric comparison of the alligator pipefish Syngnathoides biaculeatus (Bloch, 1785) from the Great Nicobar Island, India

A single female specimen (195 mm TL) of the alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785) was recorded from the coral reef rubble habitats of Gandhi Nagar, Great Nicobar Island. The present study provides a detailed morphological description of the species, including comprehensive morphometric measurements and meristic counts. This record represents important baseline information on S. biaculeatus from the Great Nicobar region, with additional details on its habitat preferences and depth distribution. Previous reports from the Andaman and Nicobar islands lacked detailed taxonomic and ecological information on the species. Therefore, the present report addresses these knowledge gaps by providing detailed taxonomic documentation, morphometric data, habitat information and photographic records of S. biaculeatus, thereby contributing valuable baseline information to the ichthyofaunal diversity of the Great Nicobar group of Islands.