Echimyini Myocastorini Echimyinae[1] is a subfamily of rodents belonging to the spiny rats family Echimyidae.

[2] It contains 14 arboreal genera—all the members of the tribe Echimyini, plus Callistomys—a few terrestrial genera (Thrichomys, Hoplomys, and Proechimys), and a subaquatic genus (Myocastor).

The first is a better understanding of the evolution of morphological characters, leading to the recognition that key character states long used to group genera into higher units were demonstrably homoplastic.

[3][4] The subfamily Echimyinae groups most of the spiny rat family's generic diversity into two tribes: Echimyini and Myocastorini.

[3] Thrichomys (punaré) Callistomys (painted tree-rat) Myocastor (nutria) Hoplomys (armored rat) Proechimys Isothrix Lonchothrix   (Tuft-tailed spiny tree-rat) Mesomys Pattonomys Toromys   (Giant tree-rat) Makalata Echimys Phyllomys Diplomys Santamartamys   (Red-crested tree-rat) Kannabateomys   (Atlantic bamboo rat) Dactylomys Olallamys