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.

[3] They are also distributed in the Río de La Plata basin and coastal rivers of southeastern Brazil.

[2] Hisonotus and Microlepidogaster have, until recently, been considered as synonymous, although they are now recognized as separate and valid taxa.

[4] In the most recent phylogenetic hypotheses, both Hisonotus and Parotocinclus are relatively basal taxa within the Otothyrini clade.