Autapomorphies of Odontostoechus lethostigmus:

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 Hyphessobrycon pulchripinnis . Some trees: Paralleled in Knodus breviceps .

2. Premaxillary, maxillary, and dentary teeth (119): (0> 1) pedunculate and uniformly shaped. Paralleled in node 232 and in Gymnocharacinus bergii .

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

4. Form of teeth of inner premaxillary tooth row (128): (0> 1) with cusps aligned in straight series and without anterior concavity. Paralleled in the Rhoadsiinae, in nodes 195, 245, and 280, and in Hemigrammus bleheri .

5. 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 Hyphessobrycon pulchripinnis . Some trees: Paralleled in node 246.