Mitochondrial genome sequencing of Biarctus sordidus (Stimpson, 1860) and phylogenetic analysis of Achelata

Abstract We sequenced and annotated the mitochondrial genome of Biarctus sordidus (Stimpson, 1860) (Achelata: Scyllaridae), obtaining a 16 017 bp circular genome containing 13 PCGs, 22 tRNAs, and 2 rRNAs, with an AT content of 65.2%. Most species within Achelata remain relatively conserved in their evolutionary patterns. Phylogenetic relationships were reconstructed using nucleotide sequences of 13 PCGs from 26 Achelata species. Both Bayesian inference and maximum likelihood analyses supported the monophyly of Palinuridae, whereas Scyllaridae showed a different topology, with Remiarctus bertholdii occupying a basal position. This placement may be related to the limited number of usable samples, differences in phylogenetic methods, or the potential effect of long-branch attraction. The results provide supplementary information on the phylogenetic relationships within Achelata.