( Ferugliotheriids ( ( may ( have ( been ( ( herbivores or ) omnivores ) ) ) ) . ) )
(ROOT (S (NP (NNS Ferugliotheriids)) (VP (MD may) (VP (VB have) (VP (VBN been) (NP (NNS herbivores) (CC or) (NNS omnivores))))) (. .)))
Ferugliotheriids may have been herbivores or omnivores.
(ROOT (S (NP (NNS Mammals)) (VP (MD may) (RB either) (VP (VB be) (NP (NNS herbivores) (, ,) (NNS omnivores) (CC or) (NNS herbivores)))) (. .)))