Autapomorphies of Hyphessobrycon pulchripinnis:

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

2. Fourth infraorbital (66): (0> 1) absent or much reduced and bordered posteriorly by third and fifth infraorbitals. Paralleled in the Aphyocharacinae and Gasteropelecidae, in node 186, and in Aphyodite grammica, Hasemania nana, Hemigrammus erythrozonus, Hoplocharax goethei, and Nematobrycon palmeri.

3. Lateral coverage of dilator fossa by sixth infraorbital (69): (1> 0) almost complete, at least in its ventral border. Paralleled in Stethaprion erythrops.

4. Number of cusps of anterior maxillary teeth (139): (0> 1) five or more cusps. Paralleled in the Rhoadsiinae, in nodes 273, 283, and 294, and in Bramocharax bransfordii, Brycon orbignyanus, Gymnocharacinus bergii, Hemibrycon dariensis, and Odontostoechus lethostigmus. Some trees: Paralleled in node 246.

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

6. Number of gill rakers on first hypobranchial and ceratobranchial (196): (0> 1) ten or fewer. Paralleled in the Characinae and in Bryconops melanurus, Iguanodectes geisleri, and Moenkhausia sanctaefilomenae. Some trees: Paralleled in node 196 and in Hemigrammus erythrozonus and Hyphessobrycon herbertaxelrodi.