First genomic analysis of Platycopioida and phylogenomics across six copepod orders.

Recent advances in bioinformatics have significantly expanded our understanding of the genetic properties of organisms and have provided valuable insights into their phylogenetic relationships and evolutionary histories. However, molecular phylogenetic studies of the class Copepoda remain limited, and the focus has been mainly on the major taxa, namely Calanoida, Cyclopoida, Harpacticoida and Siphonostomatoida. Consequently, a comprehensive phylogeny encompassing diverse copepod groups has yet to be established. In this study, we reconstructed the phylogeny of Copepoda using amino acid sequences of 40 orthologous genes, with particular emphasis on the previously understudied order Platycopioida. Our primary objectives were to confirm the generally recognized ancestral position of Platycopioida and to investigate subsequent phylogenetic changes in light of previous studies while incorporating additional copepod taxa. Our phylogenomic and statistical analyses revealed that Platycopioida represents the most basal lineage of Copepoda, which is consistent with previous morphological studies. In addition, we investigated the minor topological changes observed within the Podoplea clade, particularly in relation to the inclusion of additional copepod taxa and the use of more genetic information to improve the accuracy of phylogenetic inference.