Description: Large, narrow spine like nannofossil that tapers towards both ends and has a narrow central canal.
Remarks:
Type species: Pseudotriquetrorhabdulus inversus (Bukry & Bramlette, 1969) [Triquetrorhabdulus]
Neogene: Triquetrorhabdulus
Paleogene: Pseudotriquetrorhabdulus; Pseudotriquetrorhabdulus inversus