Myocastorini is a tribe of

echimyid Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of Hystricognathi, hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully ar ...

rodents, proposed in 2017, and containing the five extant genera '' Callistomys'', '' Hoplomys'', '' Myocastor'', ''

Proechimys ''Proechimys'' is a genus of South American South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described ...

'', and '' Thrichomys''.

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