• Cellular forms
• Domain: Eukaryota
• Kingdom: Animalia
• Subkingdom: Monocytozoa or Protozoa
• Phyllum: Ciliophora
• Class: Litostomatea
• Order: Haptorida

• Family: Mesodiniidae
• Family: Didiniidae
• Family: Enchelyidae
• Family: Fuscheriidae
• Homalozoonidae
• Family: Lacrymariidae
• Pseudotrachelocercidae
• Family: Spathidiidae
• Family: Tracheliidae
• Family: Trachelophyllidae
• Family: Enchelyodontidae