Fig. 6: Phylogenetic trees of proposed novel archaeal groups.

Phylogenetic trees of (A) Cren- and Aigarchaeota, and (B) Bathyarchaeota. Selected ZOTUs from this study are shown in pink, newly classified groups in blue. The latter include in (A) the Deeply branching Thermoprotei, the Subseafloor Sediment HWCG I Group (SSHG), and the Hot Water Crenarchaeota Groups V and VI (HWCG V and VI), and in (B) the MCG-24 through MCG-30. Trees were built in ARB using Neighbor-Joining (Jukes-Cantor Correction) and a 900-bp region column filter that leaves out insertions. Bootstrap trees (1000 replicates) were built using long reads (≥900 bp). Shorter ZOTU reads from this study and ref. ⁸ were added by ARB Parsimony (for expanded trees, see Supplementary Figs. 6 and 7). The Deeply-branching Thermoprotei were mainly present in hot layers of Orange Mat, whereas the HWCG V and VI occurred at low abundances in hot and cold sediments at various sites within the NSA and SA. Distributions of the SSHG, which was the most abundant of the new Thermoprotei groups, are discussed in the text.