Molecular and Phylogenetic Analysis of Monetaria annulus (Linnaeus, 1758) Based on Mitochondrial DNA Sequences in the Waters of Sambelia, East Lombok

The ring cowry, Monetaria annulus, occurs across the Indo-Pacific, but variation in shell morphology can complicate identification. This study examined the molecular identity and phylogenetic placement of a specimen collected from the intertidal waters of Sambelia, East Lombok, Indonesia, using the mitochondrial cytochrome c oxidase subunit I (COI) marker. The study was conducted between May 2025 and July 2026. Tissue was preserved in absolute ethanol, and DNA was extracted using a modified cetyltrimethylammonium bromide method combined with sonication. The COI region was amplified using the LCO1490 and HCO2198 primers, and the amplified DNA was sequenced. Sequence editing, database comparison and phylogenetic reconstruction were undertaken using MEGA-X, BLAST and the maximum-likelihood method with the Kimura two-parameter model and 1,000 bootstrap replicates. The specimen, designated SBL CYP 09, was identified as M. annulus. Its COI sequence showed 98.61% similarity to a reference sequence from Sambelia, East Lombok. In the reconstructed phylogenetic tree, the specimen grouped with a sequence from North Maluku, with bootstrap support of 86. The analysed specimen had a higher proportion of adenine and thymine (58.7%) than cytosine and guanine (41.2%) in its COI sequence. The findings support COI-based molecular identification of this Sambelia specimen and provide a regional sequence comparison for further studies of M. annulus.