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

This article focuses on resolving phylogenetic relationships within Asteroidea (sea stars) through the assembly and analysis of 15 new mitochondrial genomes, including the first for three families (Odontasteridae, Poraniidae, and Stichasteridae). By combining these new mitogenomes with 31 previously available sequences, the study confirms conserved mitochondrial gene order across taxa and identifies an alternative initiation codon (ATT) unique to the Pterasteridae family. Phylogenetic analyses reveal Spinulosida as a sister-group to Valvatida and Paxillosida, confirm the close relationship between Stichasteridae and Paulasteriidae, and suggest paraphyly in Pterasteridae that may warrant taxonomic revision involving Myxasteridae. These findings provide valuable molecular markers complementing nuclear data and highlight areas needing further morphological and molecular investigation to clarify sea star evolutionary history.