Range extension of a soft coral, Sarcophyton spinospiculatum Alderslade & Shirwaiker, 1991 (Cnidaria: Octocorallia) in the Andaman and Nicobar Islands, India

Aim: This study aimed to investigate the range of the soft coral Sarcophyton spinospiculatum Alderslade and Shirwaiker, 1991, from Lakshadweep in the West Coast of India to the reefs of the Andaman and Nicobar Islands in the East, significantly extending the known range of this species. Methodology: Specimen was collected from coral reef region of Kardip (08°02.3160′ N; 93°33.1601′ E), Nicobar Group of islands through SCUBA diving at depths upto 12 m. Sclerites were extracted with 5% sodium hypochlorite and examined under a microscope for taxonomic identification. Results: The species characterized by mushroom shaped colony, capitulum and stalk exterior contained club shaped sclerites (0.08 to 0.31 mm), capitulum interior sclerites were slender spindles upto 0.49 mm, with spine-like warts arranged in whorls and the stalk interior predominantly had oval sclerites (0.17–0.30 mm) with low warts. These distinctive sclerites characteristics serve as diagnostic features for identifying the species. Interpretation: This study contributes to the relatively underexplored field of octocoral research in the Nicobar Islands. These islands represent an important yet overlooked region within Indo-Pacific benthic ecosystems, which are critical to the overall health of coral reef habitats. Key words: Andaman Sea, Marine biodiversity, Polyps, Sclerites, Western Indo-Pacific