Abstract
Ophryotrocha xiamenensis is an appropriate model for investigating regeneration and evolution. The complete mitochondrial genome is 16,111 bp in length and consists of 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes and a noncoding region. Phylogenetic analysis based on concatenated sequences of all 13 PCGs using the maximum-likelihood and Bayesian methods, placed O. xiamenensis within the 'labronica' clade and the order of gene arrangement was the same as that of O. japonica. This study contributes to the development of genetic resources and advances the understanding of phylogenetic resolution within the genus Ophryotrocha.