Parent: Tockus

└─ Tockus erythrorhynchus (Red-billed hornbill)

└─── Tockus erythrorhynchus damarensis

└─── Tockus erythrorhynchus erythrorhynchus

└─── Tockus erythrorhynchus kempi

└─── Tockus erythrorhynchus ruahae

└─── Tockus erythrorhynchus rufirostris