Autapomorphies of Diapoma speculiferum:

1. Posterior extent of ventral process of quadrate (151): (0> 1) falling short of posterior margin of symplectic. Paralleled in the Hyphessobrycon luetkenii clade and Iguanodectinae, in nodes 284, 289, and 298, and in Astyanax mexicanus, A. cf. rutilus, Aulixidens eugeniae, Cyphocharax spilotus, Hemiodus cf. thayeria, Metynnis maculatus, Micralestes stormsi, Moenkhausia sanctaefilomenae, Nematocharax venustus, Probolodus heterostomus, Psellogrammus kennedyi, and Pseudocorynopoma doriae . Some trees: Paralleled in node 302.

2. Position of ventral margin of posttemporal (252): (1> 0) anterior to lateral margin of epioccipital. Paralleled in nodes 162, 285, and 301 and in Aulixidens eugeniae, Creagrutus anary, Moenkhausia cf. intermedia, and Pyrrhulina australis . Some trees: Paralleled in node 247 and in Knodus breviceps .