Autapomorphies of Mimagoniates rheocharis:

1. Synchondral articulation between lateral ethmoid and anterodorsal border of orbitosphenoid (35): (1> 0) present. Paralleled in the Aphyocharacinae and in Leporinus striatus, Pristella maxillaris, and Rhaphiodon vulpinus .

2. Small foramen near posterior margin of pterosphenoid (44): (1> 0) absent, or not pierced by nerves. Reversal of synapomorphy 1 of node 242.

3. Overlap of maxilla by second infraorbital (61): (0> 1) present. Reversal of synapomorphy 6 of node 205. Paralleled in Hollandichthys multifasciatus .

4. Bony lamella dorsal to fourth basibranchial (185): (0> 1) absent. Reversal of synapomorphy 3 of node 203. Paralleled in node 296 and in Axelrodia lindeae, Gymnocharacinus bergii, Hollandichthys multifasciatus, Nematocharax venustus, Paracheirodon axelrodi, and Prodontocharax melanotus .

5. Relative length of anterior dorsal-fin rays (271): (1> 0) not reaching tip of posterior rays when adpressed. Reversal of synapomorphy 5 of node 179.

6. Number of dorsal pterygiophores (276): (0> 1) 10 or more. Reversal of synapomorphy 3 of the Stevardiinae .

7. Anal-fin bony hooks in adult males of species bearing hooks on fins (308): (1> 0) absent.

8. Hypertrophied ventral caudal-peduncle squamation (354): (1> 0) absent. Reversal of synapomorphy 3 of node 237.

9. Caudal gland cells consisting of modified mucous cells (355): (1> 0) absent. Reversal of synapomorphy 4 of node 237.