Identifikasi Molekuler Porifera Keratosa di Pantai Tampora, Situbondo, Jawa Timur

Abstract

Porifera keratose is a group of marine sponges whose skeletons consist of spongin fibers without mineral spicules, making them difficult to identify morphologically. This study aims to identify Porifera keratose from the waters of Tampora Beach, Situbondo, East Java, using a molecular approach with the cytochrome c oxidase subunit I (COI) gene as a DNA barcode. A sample of Porifera keratose (Sp. 7), previously identified morphologically as the genus Spongia, was collected from Tampora Beach in May 2025. Molecular analysis included DNA extraction, amplification of the COI gene using primers AF 286 and AF 287, sequencing, and bioinformatics analysis via BLAST in NCBI GenBank. BLAST analysis results showed that the sample’s COI sequence had the highest similarity to Poecilosclerida sp. (Demospongiae) at 74.49%, with 90% query coverage and an e-value of 4e-85. The low identity value (<95%) indicates that identification cannot be confirmed at the genus or species level; however, it can be confirmed that the sample belongs to the class Demospongiae. Phylogenetic tree reconstruction could not be performed due to the limited availability of comparative COI sequence data for the species Spongia distans, Spongia ceylonensis, and Spongia raoi in the GenBank database. This study concludes that molecular identification using the COI gene in Porifera keratose from Tampora Beach has not yet been able to validly determine taxonomy down to the genus or species level; therefore, additional reference sequence data and the use of supplementary molecular markers are needed for more accurate identification.