Autapomorphies of Paracheirodon axelrodi:

1. Form of mesethmoid spine (27): (0> 1) relatively short, with premaxillae articulating with each other anterior to mesethmoid. Paralleled in nodes 225 and 234 and in Chalceus macrolepidotus .

2. Number of rows of premaxillary teeth (122): (1> 0) one. Paralleled in node 195 and in Aulixidens eugeniae, Carlana eigenmanni, Carnegiella strigata, Grundulus cochae, Odontostoechus lethostigmus, Piabucus melanostomus, and Probolodus heterostomus .

3. Relative length of palatine (172): (0> 1) distinctly longer than one-half length of ectopterygoid. Paralleled in nodes 197, 261, and 302 and in Hyphessobrycon pulchripinnis .

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 Prodontocharax melanotus .

5. Number of unbranched anal-fin rays (285): (1> 0) three or fewer. Paralleled in node 252 and in Iguanodectes geisleri .

Some trees:

6. Anterior articulation of epioccipital bridge (6): (0> 1) only with parietal. (k12-14). Paralleled in Grundulus cochae .

7. Expansion of lamellar portion of maxilla just posterior to toothed region (97): (0> 1) very pronounced. (k12-14). Paralleled in node 232 and in Deuterodon langei .

8. Number of maxillary teeth (135): (1> 0) only one, or absent. (k12-14). Paralleled in the Astyanax clade, in nodes 284 and 290, and in Aulixidens eugeniae, Cheirodon interruptus, Coptobrycon bilineatus, Hyphessobrycon bifasciatus, and Iguanodectes geisleri . Some trees: Paralleled in Hasemania nana and Parecbasis cyclolepis .

9. Transitional vertebrae with haemal canal (229): (1> 0) present. (k9-11). Paralleled in nodes 195 and 212, and in Aulixidens eugeniae, Engraulisoma taeniatum, Metynnis maculatus, and Piabina argentea . Some trees: Paralleled in node 247 and in Bryconamericus alpha .

10. Dorsal-fin rays articulating with first dorsal pterygiophore (266): (1> 0) two. (k12-14). Reversal of synapomorphy 4 of node 203. Paralleled in Bario steindachneri and Thayeria obliqua. Some trees: Paralleled in Hyphessobrycon elachys . 11. Insertion of pterotic aponeurosis (340): (0> 2) on pterotic or sphenotic, distinctly dorsal to horizontal semicircular canal. (k12-14). Some trees: Paralleled in Hyphessobrycon elachys .