The blood cockle, Tegillarca granosa, is one of the key member of shellfish communities that are ecologically and economically important specially in Indonesia. We collected samples from four sites in Indonesia: Banyuwangi, Bali Island, Maros and Buru Island. Nucleotide sequence analysis was performed on PCR-amplified mitochondrial DNA COI gene. In total, 556-558 base pair nucleotide sequences were obtained from 12 individuals. Molecular analyses revealed samples belonging to the T. granosa species. Phylogenetic analyses were carried out by comparing the gene sequences of T. granosa haplotypes in Indonesia with gene sequences of the same base pair length and with the of Anadara tuberculosa which was used as an outgroup. The phylogenetic trees were consistent and indicated in the two sub-clades. The presence of T. granosa and the phylogenetic status of the T. granosa Indonesian haplotype were reported. Clarifying the phylogenetic status of ecologically important species provides basic information studies for possible future conservation and control programs.
