`` O. pliocaenicus '' as a Pliocene North American species of `` Jacobsomys '' , a questionable genus which he said may be ancestral to `` Oryzomys '' .
`` O. pliocaenicus '' as a questionable species of `` Jacobsomys '' , a Pliocene North American genus which he said may be ancestral to `` Oryzomys '' .