Autapomorphies of Prodontocharax melanotus:

1. Margins of toothed region of maxilla (96): (0> 1) dorsally divergent. Paralleled in nodes 162, 209, 254, and 282 and in Rhoadsia altipinna .

2. Extent of implantation of teeth along maxilla (137): (0> 1) extending across almost entire maxillary lamella. Reversal of synapomorphy 1 of node 202. Paralleled in node 208 and in Grundulus cochae, Hemibrycon surinamensis, and Nematobrycon palmeri .

3. Orientation of anterior dentary teeth (141): (0> 1) oriented anteriorly, almost parallel to main axis of dentary. Paralleled in node 225.

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, Mimagoniates rheocharis, Nematocharax venustus, and Paracheirodon axelrodi .

5. Form of anterior expansion of basihyal (191): (0> 1) expanded, with anterior margin with two-thirds or more of its length. Paralleled in Aulixidens eugeniae, Cyphocharax spilotus, and Thayeria obliqua.

6. Rows of gill rakers on first ceratobranchial (192): (0> 1) two. Reversal of synapomorphy 3 of node 179. Paralleled in the Iguanodectinae, in node 280, and in Brycon orbignyanus, Bryconaethiops macrops, Carlana eigenmanni, Cheirodon interruptus, Hoplocharax goethei, Hyphessobrycon elachys, Odontostilbe microcephala, Parecbasis cyclolepis, and Rhaphiodon vulpinus . Some trees: Paralleled in node 249 and in Attonitus ephimeros .

7. Bony lamellae associated with supraneurals (282):(0> 1) wider than primary axis of supraneurals. Reversal of synapomorphy 5 of node 197. Paralleled in Parecbasis cyclolepis .

8. Number of branched anal-fin rays (287): (1> 0) 17 or less. Reversal of synapomorphy 6 of the Characoidea . Paralleled in the Alestidae, in nodes 280 and 290, and in Attonitus ephimeros . Some trees: Paralleled in Hasemania nana .

9. Contact between dorsal margin of adductor mandibulae and ventral margin of dilator operculi (335): (1> 0) absent. Paralleled in Creagrutus anary, Inpaichthys kerri, Piabucus melanostomus, Prionobrama paraguayensis, Pristella maxillaris, and Pyrrhulina australis . Some trees: Paralleled in Hyphessobrycon elachys .