Autapomorphies of Bario steindachneri:

1. Contact between frontals anteriorly to frontal fontanel (21): (0> 1) present. Reversal of synapomorphy 4 of node 206. Paralleled in Exodon paradoxus, Galeocharax humeralis, Hyphessobrycon pulchripinnis, and Odontostoechus lethostigmus . Some trees: Paralleled in Knodus breviceps .

2. Dorsal end of laterosensory canal of preopercle and suprapreopercle (82): (0> 1) overlapping anterodorsal process of opercle. Paralleled in the Alestidae, in node 230, and in Hyphessobrycon eques, Parecbasis cyclolepis, Pristella maxillaris, and Stichonodon insignis .

3. Ventral margin of horizontal process of anguloarticular (109): (0> 1) perpendicular to laterosensory canal of dentary from medial view. Paralleled in node 199 and in Bramocharax bransfordii and Micralestes stormsi .

4. Dorsal-fin rays articulating with first dorsal pterygiophore (266): (1> 0) two. Reversal of synapomorphy 4 of node 203. Paralleled in Thayeria obliqua. Some trees: Paralleled in Hyphessobrycon elachys and Paracheirodon axelrodi .

5. Pectoral-fin bony hooks in adult males of species bearing hooks on fins (310): (0> 1) present. Paralleled in node 268 and in Astyanax cf. asuncionensis, A. lineatus, Bryconamericus cf. iheringii, B. rubropictus, Hyphessobrycon luetkenii, H. socolofi, and Phenacogaster tegatus .

6. Dorsal-fin bony hooks in adult males of species bearing hooks on fins (311): (0> 1) present. Paralleled in nodes 248 and 268 and in Astyanax cf. asuncionensis, A. lineatus, Bryconamericus rubropictus, Hyphessobrycon luetkenii, H. socolofi, Nematocharax venustus, and Probolodus heterostomus .

7. Caudal-fin bony hooks in adult males of species bearing hooks on fins (312): (0> 1) present. Paralleled in node 268 and in Acrobrycon tarijae, Astyanax cf. asuncionensis, A. lineatus, Hyphessobrycon luetkenii, H. socolofi, and Probolodus heterostomus .

8. Scales covering anal-fin base (327): (0> 1) several rows covering basal third of anal fin. Paralleled in the Serrasalmidae, in nodes 210 and 221, and in Markiana nigripinnis, Paragoniates alburnus, Rhaphiodon vulpinus, Roeboides microlepis, and Thoracocharax stellatus .