Autapomorphies of Metynnis maculatus:

1. Contact between frontals anteriorly to frontal fontanel (21): (1> 0) absent. Paralleled in node 167. Some trees: Paralleled in nodes 175 and 206 and in Brycon meeki .

2. Anterior margin of supraoccipital (51): (0> 1) situated anterior to vertical through posterior orbital margin. Paralleled in node 220 and in Cynopotamus argenteus .

3. Lateral surface of vertical canal of preopercle (81): (1> 0) canal uncovered and situated posteriorly to musculature and infraorbitals. Paralleled in nodes 170, 175, and 204 and in Chalceus macrolepidotus .

4. Posterior extent of ventral process of quadrate (151): (0> 1) falling short of posterior margin of symplectic. Paralleled in the Hyphessobrycon luetkenii clade and Iguanodectinae, in nodes 284, 289, and 298, and in Astyanax mexicanus, A. cf. rutilus, Aulixidens eugeniae, Cyphocharax spilotus, Diapoma speculiferum, Hemiodus cf. thayeria, Micralestes stormsi, Moenkhausia sanctaefilomenae, Nematocharax venustus, Probolodus heterostomus, Psellogrammus kennedyi, and Pseudocorynopoma doriae . Some trees: Paralleled in node 302.

5. Cartilages anterior to basihyal (188): (0> 1) two well developed blocks of cartilage. Paralleled in nodes 244 and 299 and in Hasemania nana, Hyphessobrycon bifasciatus, Odontostilbe microcephala Eigenmann, and Roeboides descalvadensis . Some trees: Paralleled in node 265.

6. Transitional vertebrae with haemal canal (229): (0> 1) absent. Paralleled in nodes 195 and 212, and in Aulixidens eugeniae, Engraulisoma taeniatum, and Piabina argentea . Some trees: Paralleled in node 247 and in Bryconamericus alpha and Paracheirodon axelrodi .

7. Dorsal-fin rays articulating with first dorsal pterygiophore (266): (0> 1) three or four. Paralleled in nodes 203 and 276 and in Salminus brasiliensis . Some trees: Paralleled in Brycon orbignyanus .

8. Number of branched anal-fin rays (289): (0> 1) 35 or more. Paralleled in nodes 207 and 212 and in Gymnocorymbus ternetzi, Piabucus melanostomus, Pseudocorynopoma doriae, Rhaphiodon vulpinus, Stethaprion erythrops, and Thoracocharax stellatus . Some trees: Paralleled in node 261 and in Markiana nigripinnis .