Typhloplanoida Graff, 1908 see Suborder Typhloplanida
   Family Trigonostomidae Graff, 1905 (1882)
     Genus Trigonostomum Schmidt, 1852
       01 Trigonostomum franki W.R. Willems et al., 2004
       02 Trigonostomum nataschae W.R. Willems et al., 2004
       03 Trigonostomum spinigerum W.R. Willems et al., 2004
       04 Trigonostomum watsoni W.R. Willems et al., 2004
       05.1.1 Trigonostomum tori W.R. Willems et al., 2004
       05.1.2 Trigonostomum galapagoensis W.R. Willems et al., 2004
       05.1.3 Trigonostomum setigerum O. Schmidt, 1852
       05.2 Trigonostomum australis W.R. Willems et al., 2004
       06 Trigonostomum denhartogi (Karling, 1978)
       07 Trigonostomum penicillatum (O. Schmidt, 1857) Micoletzky, 1910
       07.0 Trigonostomum marki Graff, 1911 see Trigonostomum penicillatum (O. Schmidt, 1857) Micoletzky, 1910
       08 Trigonostomum lilliei (Graff, 1911)
       08.0.1 Trigonostomum prytherchi Kepner et al., 1941 see Trigonostomum lilliei (Graff, 1911)
       08.0.2 Trigonostomum divae Marcus, 1948 see Trigonostomum lilliei (Graff, 1911)
       09 Trigonostomum coronatum (von Graff, 1882) von Graff, 1913
       09.0.1 Trigonostomum intermedium Graff, 1910 see Trigonostomum coronatum (von Graff, 1882) von Graff, 1913
       09.0.2 Trigonostomum quadrifolium Riedl, 1954 see Trigonostomum coronatum (von Graff, 1882) von Graff, 1913
       10 Trigonostomum brunchorsti von Graff, 1905, nom. inq.
       11 Trigonostomum piriforme (Pereyaslawzewa, 1892) von Graff, 1905, nom. inq.