Definition
Myocastorini members share long upper incisor roots (except ''Callistomys''), and mid- to long-sized lower incisor roots. These five genera share either four (''Callistomys'', ''Thrichomys'') or five (''Hoplomys'', ''Myocastor'', ''Proechimys'') lophids on the lower deciduous fourth premolar, three roots anchoring the upper molars, and well-connected lophs on cheek teeth. Members display a variety of lifestyles including terrestrial (''Hoplomys'', ''Proechimys'', ''Thrichomys''), arboreal (''Callistomys''), and amphibious (''Myocastor'') adaptations.Phylogeny
On the one hand, the genus ''Proechimys'' is the sister group to the genus ''Hoplomys'' (armored rats), and both form a clade of lowland rainforest terrestrial spiny rats. On the other hand, ''Callistomys'' (painted tree-rats) is the sister group to ''Myocastor'' (coypus). In turn, these two pairs of genera share evolutionary affinities with ''Thrichomys'' (punaré).References
Echimyinae Mammal tribes {{rodent-stub