FIG. 2.

Phylogenetic tree based on parsimony analysis of 16S rRNA gene sequences for deep-subsurface and type strains of Arthrobacter species. For the deep-subsurface strains, the soil sample identifier and stratum from which they originate are indicated. FG and , fluvial gravel; FS and ▵, fluvial sand; LC and ■, lacustrine; LP and ★, lower paleosol; UL and ○, upper lacustrine; UP and ▴, upper paleosol. The tree is rooted using S. ambofaciens as an outgroup. Numbers at the nodes indicate the percentages of occurrence in 100 bootstrapped trees; only values that are 50% or greater are shown.