The first complete mitochondrial genome and phylogenetic analysis of deep-sea asteroid, Leptychaster arcticus (Valvatacea: Paxillosida: Astropectinidae).

The complete mitochondrial genome of Leptychaster arcticus, deep-sea inhabited asteroid, was examined in this study. The complete mitogenome of L. arcticus is 16,253 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. No gene rearrangements or deletions were observed in compared to other Paxillosida. The ND4L and ND3 genes have 'ATT' as its start codon, which is a feature that has been found in previous echinoderm mitochondrial studies. In the ML tree analysis based on the superorder Valvatacea, it was difficult to establish the molecular phylogenetic relationship at lower taxonomic levels, such as order and family, due to the lack of asteroid molecular data available. Therefore, we expect to contribute to the expansion of the data and determine the phylogenetic positioning in future studies.