Definition that contains type a
- lycopodium type and sole genus of the Lycopodiaceae; erect or creeping evergreen plants often used for Christmas decorations
- isoetes type and genus of the Isoetaceae and sole extant genus of the order Isoetales
- genus albula type and sole genus of the family Albulidae
- casuarius type and sole genus of the Casuaridae: cassowaries
- symplocus type and sole genus of Symplocaceae including sweetleaf
- selaginella type and sole genus of the Selaginellaceae; evergreen moss-like plants: spike moss and little club moss
- odontaspis type and sole genus of Carchariidae: sand sharks
- carcharias type and sole genus of Carchariidae: sand sharks
- liopelma type and sole genus of the family Leiopelmatidae
- genus esox type and only genus of the family Esocidae