the root (no rank)
Eukaryota (domain)
Metazoa (kingdom)
Nematoda (phylum)
Adenophorea (class)
Mermithida (order)
Mermithioidea (suborder)
Mermithidae (family)
[hide inferior taxa]
Mermis nigrescens (species)
Romanomermis culicivorax (species)