the root (no rank)
Viruses (domain)
retroid viruses (subkingdom)
Retroviridae (family)
Orthoretrovirinae (subfamily)
Betaretrovirus (genus)
Mason-Pfizer monkey virus (species)
[hide inferior taxa]
human endogenous retrovirus type D (subspecies)
simian AIDS retrovirus SRV-1 (subspecies)
simian retrovirus 2 (subspecies)
simian retrovirus SRV-2 (subspecies)
simian retrovirus type D (subspecies)