the root (no rank)
Eukaryota (domain)
Metazoa (kingdom)
Chordata (phylum)
Craniata (subphylum)
Vertebrata (no rank)
Gnathostomata (superclass)
Sarcopterygii (class)
Tetrapoda (no rank)
Amniota (no rank)
Sauropsida (no rank)
Sauria (no rank)
Lepidosauria (superorder)
Squamata (order)
Serpentes (suborder)
Colubroidea (superfamily)
Viperidae (family)
Crotalinae (subfamily)
Agkistrodon (genus)
Agkistrodon halys (species)
Agkistrodon halys pallas (subspecies)
[hide inferior taxa]