the root (no rank)
Viruses (domain)
retroid viruses (subkingdom)
Retroviridae (family)
Orthoretrovirinae (subfamily)
Lentivirus (genus)
simian immunodeficiency virus (species)
[hide inferior taxa]
human T-cell lymphotropic virus type 4 (subspecies)
simian immunodeficiency virus SIVagm (subspecies)