biostudies-literatureZhao HNational Key R&amp;D Program of ChinaCentral Public-interest Scientific Institution Basal Research Fund, CAFS911-914https://www.ebi.ac.uk/biostudies/studies/S-EPMC11285236biostudies-literatureUnknown9(7)<i>Cirriformia</i> species usually inhabit intertidal zones and deep-sea sediments. Their accurate identification has proven to be challenging. Here, we present the complete mitochondrial genome of one <i>Cirriformia tentaculata_</i>Montagu 1808 specimen collected from China. The total length of the complete mitochondrial sequence of <i>C. tentaculata</i> is 15,516 bp and consists of 13 protein-coding genes (PCGs), 23 tRNA genes, two rRNA genes, and an A + T rich region (64.20%). All PCGs begin with the typical ATN start codon, except for <i>cox1</i>, which uses TTG. TAA or TAG serve as termination codons for twelve PCGs, while <i>nad5</i> terminates with an incomplete codon, T. The phylogenetic tree revealed a close relationship between <i>C. tentaculata</i> in this study, and <i>CirriforMitochondrial DNA. Part B, ResourcesComplete mitochondrial genome and phylogenetic analysis of <i>Cirriformia tentaculata</i> (Annelida, Polychaeta, Cirratulidae) from Weihai, Shandong, China.PMC112852362023YFD24007052023TD292023YFD2400700Yuan CRong XGe JWang YLiao MWang JCui QZhao HfalseComplete mitochondrial genome and phylogenetic analysis of <i>Cirriformia tentaculata</i> (Annelida, Polychaeta, Cirratulidae) from Weihai, Shandong, China.<i>Cirriformia</i> species usually inhabit intertidal zones and deep-sea sediments. Their accurate identification has proven to be challenging. Here, we present the complete mitochondrial genome of one <i>Cirriformia tentaculata_</i>Montagu 1808 specimen collected from China. The total length of the complete mitochondrial sequence of <i>C. tentaculata</i> is 15,516 bp and consists of 13 protein-coding genes (PCGs), 23 tRNA genes, two rRNA genes, and an A + T rich region (64.20%). All PCGs begin with the typical ATN start codon, except for <i>cox1</i>, which uses TTG. TAA or TAG serve as termination codons for twelve PCGs, while <i>nad5</i> terminates with an incomplete codon, T. The phylogenetic tree revealed a close relationship between <i>C. tentaculata</i> in this study, and <i>Cirrifor2024-01-01T00:00:00Z20242026-05-22T03:20:55.162Z2026-05-22T03:07:35.206ZS-EPMC112852363907706110.1080/23802359.2024.2381783