to this family: a premaxillary tooth was found in the Colombian Villavieja Formation and dated to the Laventan age about 13.5-11.5 Mya, while some pharyngeal teeth and other jaw parts found near Cuenca, Ecuador in the Cuenca basin (a structural basin) are about 19 million years old. The fossil remains resemble Leporinus and were assigned to the living genus, but given its paraphyly and rather basal position, until more fossils are found the known remains can only be considered fairly basal Anostomidae, incertae sedis, but probably close to the Leporinus assemblage. Cyphocharax mosesi, a fossil toothless characin found in Brazil, lived at the Oligocene-Miocene boundary about 23 Mya. Thus, at that time, the Anostomoidea families must have already been well distinct. Given that the Characiformes originated slightly more than 115 Mya, the Anostomoidea probably diverged from their characiform relatives the Late Cretaceous and diversified thereafter; a Paleogene origin of the Anostomidae is thus most likely, with present-day subfamilies (whatever eventually will be accepted) having diverged by the start of the Neogene. Whether the family originated in Oligocene or already in the Eocene (or perhaps even in the Paleocene) cannot be said until more fossil material is recovered, either to answer this question directly or to provide calibration for molecular phylogenetic studies. Genera The genera of Anostomidae are: Basal lineages Abramites (two species) Anostomoides (three species) Hypomasticus (seven species) Leporellus (four species) Leporinus (79 species; paraphyletic) Megaleporinus (10 species) Schizodon clade Rhytiodus (four species) Schizodon (16 species)Anostominae sensu stricto Anostomus (five species) Gnathodolus (one species) Laemolyta (9 species) Petulanos (three species) Pseudanos (four species; paraphyletic?) Sartor (three species) Synaptolaemus (two species) In Brazil, many species of Leporinus, Rhytiodus, and Schizodon are called aracu. References Further reading Filleul, Arnaud & Maisey, John G. (2004): Redescription of Santanichthys diasii (Otophysi, Characiformes) from the Albian of the Santana Formation and comments on its implications for otophysan relationships. American Museum Novitates 3455: 1-21. PDF fulltext FishBase (2004): Family Anostomidae - Headstanders. Version of 2004-NOV-22. Retrieved 2009-FEB-26. Sidlauskas, Brian L. & Vari, Richard P. (2008): Phylogenetic relationships within the South American fish family Anostomidae (Teleostei, Ostariophysi, Characiformes). Zool. J. Linn. Soc. 154(1): 70–210. (HTML abstract) Weitzman, S.H. & Vari, Richard P. (1998): [Anostomidae]. In: Paxton, J.R. & Eschmeyer, W.N. (eds.): Encyclopedia of Fishes: 104. Academic Press, San Diego. Fish of South America Taxa named by Albert Günther