The Complete Mitochondrial Genomes of Babylonia spirata and Babylonia zeylanica (Neogastropoda: Babyloniidae) Provide New Insights into Neogastropoda Phylogeny.

The genus Babylonia, classified under Mollusca, Gastropoda, Neogastropoda, has been a subject of controversy concerning the phylogenetic relationships within Neogastropoda, a highly intricate group of predatory marine snails. In this study, we sequenced complete mitogenomes of Babylonia spirata and Babylonia zeylanica. Both mitogenomes consist of 37 genes, including 13 PCGs, 22 tRNAs, and 2 rRNAs, which is consistent with the gene numbers observed in most neogastropod snails. We analyzed base content, codon usage preference, and tRNA structure to describe the basic structural features. Additionally, phylogenetic trees were constructed using Maximum Likelihood and Bayesian Inference based on the complete mitogenomes of 43 Neogastropoda species. This analysis revealed that all 19 families formed monophyletic groups, collectively constituting seven monophyletic superfamilies. Moreover, by analyzing the gene arrangement characteristics of these 43 Neogastropoda species, we identified four distinct types of mitochondrial genome arrangements. This study strongly supports the monophyly of Neogastropoda families, contradicting previous molecular studies and providing fundamental insights for further phylogenetic studies in Neogastropoda.