The family Coralliidae (Octocorallia) includes ecologically and economically important octocorals that build rigid, three‐dimensional skeletal frameworks from shallow reefs to the deep sea. Despite extensive morphological study, species boundaries remain difficult to delimit because of morphological convergence, phenotypic plasticity, and the limited resolution of commonly used molecular markers. During benthic surveys in the Xisha Islands, South China Sea, we discovered a new coralliid species, Paraminabea xishaensis sp. nov. The new species resembles P. aldersladei in overall colony form but can be distinguished by a consistent suite of diagnostic sclerite characters, most notably stalk sclerites with a continuous transverse groove and the presence of six‐ to eight‐radiate forms approaching double stars; autozooid and siphonozooid pores were not apparent. Phylogenomic analyses based on 2903 ultraconserved element (UCE) loci recover P. xishaensis sp. nov. as sister to P. aldersladei with strong support within a family‐wide UCE phylogeny framework of Coralliidae, consistent with its recognition as a distinct species. The phylogeny further recovers five deeply divergent and internally coherent lineages within Coralliidae: Sphaerasclera , Paraminabea , a clade comprising Sibogagorgia , Paragorgia , Hemicorallium , Corallium , and Pleurocorallium , Minabea , and Anthomastinae. This phylogenomic framework provides a comparative baseline for future studies that incorporate expanded sampling and genome‐derived single‐copy orthologs to investigate adaptive evolution, mitonuclear discordance, and ecological diversification across Coralliidae.
Luan et al. (Thu,) studied this question.