the root (no rank)
Bacteria (domain)
Proteobacteria (phylum)
Gammaproteobacteria (class)
Acidithiobacillales (order)
Acidithiobacillaceae (family)
[hide inferior taxa]
Acidithiobacillus caldus (species)
Acidithiobacillus ferrooxidans (species)
Acidithiobacillus thiooxidans (species)