*3.1. Phylogenomic Analysis*

Representative genomes for *Zobellia* and related genera were retrieved from GenBank, NCBI. Accession numbers for the genomes used in this study are provided in Table S1. Single-copy marker genes (*n* = 400) were selected from protein sequences, concatenated, and aligned using the PhyloPhlAn (version 3.0) pipeline [22]. A maximum-likelihood tree was reconstructed by RAxML (version 8.2.12) under the LG+Γ model with non-parametric bootstrapping using 100 replicates [34].
