Denser Mitogenomic Sampling for Exploring the Phylogeny of Tellinoidea (Mollusca: Bivalvia)

The superfamily Tellinoidea is one of the most diverse groups of marine bivalves, with significant ecological and economic value. To date, the availability of complete mitochondrial genome data within Tellinoidea remains limited, and the taxonomic coverage is still insufficient to resolve its internal controversies. The current study aims to further explore the phylogenetic relationships within Tellinoidea through denser sampling. We have newly sequenced the mitochondrial genomes of 13 species, among which seven genera are being published for the first time. Combined with the published mitogenomes and transcriptomic data, we constructed the most comprehensive Tellinoidea phylogeny to date through maximum likelihood and Bayesian Inference analyses. Our findings support the monophyly of the superfamily Tellinoidea, with Semelidae nesting as a monophyletic group within Tellinidae. We also support the paraphyly of Tellinidae based on the mitochondrial genome data for the first time, identifying that the two subfamilies (Macominae and Tellininae) are polyphyletic. Gene rearrangement analysis reveals a relatively high degree of variation in Semelidae. By expanding the mitochondrial genome dataset, this study provides new insights into the phylogeny of Tellinoidea and underscores the need for further sampling of species to reassess the phylogenetic relationships of Tellinidae and the entire Tellinoidea.