Implications of extensive addition of new sea star mitogenomes for sea star phylogenetics and evolution (Echinodermata: Asteroidea)

Despite their ecological and evolutionary interests, the phylogeny of Asteroidea (sea stars) is still subject to debate at several taxonomic levels. In the present study, we assemble new mitochondrial genomes for 15 species, including three newly characterized families (Odontasteridae, Poraniidae, and Stichasteridae) and representing an important addition for two orders (Velatida and Spinulosida). By analysing them alongside the 31 previously available mitogenomes, we evaluate mitogenomic variation (mitogenome organization and phylogenetic relationships) within the class. Gene order and sizes were concordant with previous studies. However, an alternative initiation codon (ATT for NAD1) was found in two Pterasteridae species. Evolutionary patterns between orders provided some interesting insights (e.g. Spinulosida as the sister-group to the Valvatida + Paxillosida), but the most novel patterns were observed among families (e.g. close relationships of Stichasteridae and Paulasteriidae; close relationships of Odontasteridae and Poraniidae; Brisingidae and Freyellidae as sister-group to the Asteriidae, Paulasteridae, and Stichasteridae). Finally, we found Pterasteridae to be paraphyletic, which could lead to the incorporation of Myxasteridae within Pterasteridae. Altogether, this study confirms that mitogenomes provide valuable and cost-effective markers to complement evolutionary patterns derived from nuclear data.

Peer Review, Impact Factor

https://doi.org/10.1093/zoolinnean/zlae140