Abstract
Poliometra prolixa Sladen, 1881, is a comatulid crinoid found in the Arctic deep sea. In this study, we report the complete mitochondrial genome sequence of P. prolixa (Comatulida: Antedonidae). The complete mitogenome of P. prolixa was 15,916 bp long and comprised 13 protein-coding genes (PCGs), 22 transfer RNA genes, and 2 ribosomal RNA genes. The base composition of the P. prolixa mitogenome was 24.0% A, 44.9% T, 19.0% G, and 12.1% C. Phylogenetic analysis using all PCGs of the complete mitogenome confirmed the inclusion of P. prolixa within the Comatulida.