Systematic revision of <i>Gyriabrus</i> (Rodentia, Caviomorpha), a large dinomyid from the Neogene of South America

Dinomyidae is a family of rodents including one extant species, Dinomys branickii, but with high past diversity. Gyriabrus large dinomyid euhypsodont cheek teeth and an occlusal pattern that changes throughout the ontogeny animal. Eight species have been described in late Miocene to Pliocene Argentina, Uruguay, Colombia Brazil. The taxonomic status has questioned, being considered as juvenile forms other dinomyids. According this study, unique dental anatomy among dinomyids valid genus. A study permitted propose ontogenetic series. All from Argentina (Ituzaingó Formation) Uruguay (Camacho belong holmbergi (including G. glutinatus, rebagliattii, indivisus teisseirei), representing different wear stages. ?Gyriabrus quadratus, latidens (late Pliocene? Argentina) ?G. royoi Miocene-Pliocene Colombia), all based on isolated teeth, are pending future findings allow deeper comparison. This contributes knowledge systematics, taxonomy extinct Dinomyidae, which essential for studies evolutionary history group.