Oryzomyini, also known as rice rats, is a diverse grouping of North, Central, and South American rodents within the family Cricetidae.
Cladistic analysis of morphological characters suggest that Pennatomys is most closely related to a clade, the Nectomys subclade, that includes members of Aegialomys, Amphinectomys, Nectomys, Sigmodontomys, Melanomys, Megalomys (another Antillean rice rat), and possibly Nesoryzomys.