Molecular identification and phylogenetic analysis of coral and megabenthic species from Gede Island, Central Java, Indonesia

Coral reef ecosystems are home to many organisms, including bivalves, gastropods, crinoids, and demersal fish, making biodiversity assessment crucial for effective conservation and management. This study aims to: i) apply DNA barcoding to identify coral and megabenthic species in coral reef ecosystems, and ii) construct phylogenetic tree to trace their evolutionary relationships. Using quantitative descriptive methods and purposive sampling, specimens were collected in July 2023. The study yielded one coral (R2), one hydrozoan (R3), and one gastropod (GP-1) sample were successfully barcoded. DNA barcoding through Cytochrome Oxydase I (COI) gene amplification revealed that sample R2 had a 98.70% similarity with Acropora hyacinthus, sample R3 had a 98.92% similarity with Zanclea galli, and sample GP-1 had a 91.19% similarity with Erronea errones. Phylogenetic analysis positioned R2 in the same clade as Acropora hyacinthus and related genera such as Montipora, Astreopora, and Alveopora, within the Acroporidae family. R3 clustered with Zanclea galli in the hydrozoan group, alongside Z. sesillis, Z. implexa, and Z. sango. GP-1 grouped with Erronea errones in the gastropod genus Erronea, showing relationships with other genera such as Blasicrura, Cribrarula, Bistolida, and Eclogavena within the subfamily Erroneinae. Species inventories like this are essential for the conservation and management of coral reefs, which are key habitats for fish and other marine life.