Figure 1.

Neighbor joining tree based on 16S rRNA gene sequences showing the phylogenetic affiliations of Desulfotomaculum and related species and highlighted to show the subgroups of Desulfotomaculum cluster 1. D. gibsoniae is printed in bold type. The recently described Desulfotomaculum defluvii (cluster 1a), Desulfotomaculum intricatum (cluster 1f), Desulfotomaculum peckii (cluster 1e), and Desulfotomaculum varum (cluster 1a) and the entire cluster 1g are not included in the tree. A set of Thermotogales species were used as outgroup, but were pruned from the tree. Closed circles represent bootstrap values between 75 and 100%. The scale bar represents 10% sequence difference.