Related how?

Biota (Life)
Eukaryote (Eukarya)
Chromista
Harosa
Halvaria
Alveolate (Alveolata)
Ciliophora (Ciliates)
Oligohymenophorea
Hymenostome (Hymenostomatia)

Tetrahymenina (18670523)

Children (2 direct children, 22 direct and indirect children):

Didiniidae (tree size 14)

Turaniellidae (tree size 6)