Autapomorphies of Deuterodon langei:

1. Expansion of lamellar portion of maxilla just posterior to toothed region (97): (0> 1) very pronounced. Paralleled in node 232. Some trees: Paralleled in Paracheirodon axelrodi .

2. Articulation between ventral margin of metapterygoid and posterodorsal margin of quadrate (155): (0> 1) present. Paralleled in nodes 176 and 299 and in Heterocharax macrolepis, Pristella maxillaris, Roeboides descalvadensis, and Thoracocharax stellatus .

3. Distribution of denticles on gill rakers (202): (0> 1) along entire surface of gill rakers. Paralleled in node 269 and in Astyanax correntinus, Hoplias cf. malabaricus, Hyphessobrycon eques, and Pristella maxillaris .

4. Development of transverse process of neural arch of third vertebra (219): (0> 1) well developed and extending beyond anterior margin of tripus. Paralleled in node 302, and in Agoniates anchovia, Cyanocharax alburnus, Engraulisoma taeniatum, Hemiodus cf. thayeria, Roeboexodon geryi, and Thayeria obliqua. Some trees: Paralleled in Microschemobrycon casiquiare and Parecbasis cyclolepis .

5. Process of scapula forming anterior border of scapular foramen (244): (0> 1) absent. Paralleled in nodes 193 and 252 and in Aphyodite grammica, Hoplias cf. malabaricus, Hyphessobrycon herbertaxelrodi, Leporinus striatus, Odontostilbe paraguayensis, and Thayeria obliqua.