Position in a system
| system | Vitae - living organisms |
| domain | Eukaryota Whittaker & Margulis, 1978 - lifeforms with nucletic cells |
| superregnum | Unikonta |
| system | Opisthokonta Cavalier-Smith, 1987 |
| kingdom | Animalia Linnaeus, 1758 - animals |
| subregnum | Eumetazoa Butschli, 1910 |
| divisio | Bilateria Hatschek, 1888 - bilaterians |
| subdivisio | Protostomia Grobben, 1908 - protostomes |
| phylum | Nematoda Rudolphi, 1808 - nematodes |
| class | Adenophorea von Linstow, 1905 |
| subclass | Enoplia Pearse, 1942 |
| order | Enoplida Filipjev, 1929 |
| suborder | Trefusiina |
| superfamily | Trefusioidea |
| family | Trefusiidae Gerlach, 1966 |
| genus | Trefusia de Man, 1893 |
| species | Trefusia varians Gerlach, 1955 |