Hisonotus is a genus of armored catfishes native to South America. Species of Hisonotus and Curculionichthys are the only representatives of the subfamily Otothyrinae having serrae on the posterior edge of the pectoral fin spine. These species are small fishes, generally found in small fast flowing streams, where they grasp to the branches and leaves of aquatic or subaquatic plants. The species of this genus mostly occur in Atlantic coastal streams of southern Brazil and the Paraguay-Paraná system of southern South America. They are also distributed in the Río de La Plata basin and coastal rivers of southeastern Brazil.
Hisonotus and Microlepidogaster have, until recently, been considered as synonymous, although they are now recognized as separate and valid taxa. In the most recent phylogenetic hypotheses, both Hisonotus and Parotocinclus are relatively basal taxa within the Otothyrini clade.
Species
There are currently 33 recognized species in this genus:
Hisonotus acuen G. S. C. Silva, Roxo & C. de Oliveira, 2014
