The First Complete Mitochondrial Genome of Eucrate crenata (Decapoda: Brachyura: Goneplacidae) and Phylogenetic Relationships within Infraorder Brachyura

Characterizing the complete mitochondrial genome (mitogenome) of an organism is useful for genomic studies in taxonomy and evolution. The mitogenomic characteristics of Eucrate crenata (Decapoda: Brachyura: Goneplacidae) have never been studied. The present study decodes the first mitogenome of E. crenata by high-throughput sequencing (HTS). The length of the mitogenome is 15,597 bp, and it contains 13 protein-coding genes, 2 ribosomal RNA genes (rrnS and rrnL), and 22 transfer RNA genes. There are 14 and 23 genes observed on the heavy and light strands, respectively. E. crenata possesses a trnH-cac translocation, with the trnH-cac shifted between trnE-gaa and trnF-ttc instead of the usual location between nad5 and nad4 in decapods. Phylogenetic analyses based on the current dataset of 33 Brachyuran mitogenomes indicate that E. crenata. is closely related to Ashtoret lunaris of Matutidae. The similar codon usage and rearrangements in the two species provide evidence for their close phylogenetic relationship. Positive selection analysis showed that one residue located in cox1 was identified as a positively selected site with high BEB value (>95%), indicating that this gene was under positive selection pressure. This study is the first complete mitogenome record for the family Goneplacidae, and the results obtained may improve the understanding of the phylogeny of Goneplacidae in Brachyura.