Sistrurus
Sistrurus is a genus of venomous pit vipers in the subfamily Crotalinae of the family Viperidae . 
<triplet> genus <subj> subfamily <obj> part of <triplet> pit viper <subj> Viperidae <obj> parent taxon <triplet> subfamily <subj> family <obj> part of <triplet> Crotalinae <subj> Viperidae <obj> parent taxon