Brasinorhynchus is an extinct genus of derived stenaulorhynchine known from the late Middle Triassic (Ladinian stage) Santa Maria Formation of Rio Grande do Sul, Brazil.

[2] B. mariantensis is known from two specimens, including the holotype UFRGS-PV-0168-T, a complete skull, atlas, axis and third neck vertebra and the paratype UFRGS-PV-0315-T, right maxilla and jaw, both housed at the vertebrate paleontology collection of the Universidade Federal do Rio Grande do Sul, Porto Alegre-Brazil.

The specimens were collected at the same site, along road RS-240 near the town of Porto Mariante, 28 km east of Venâncio Aires, in the municipality of Bom Retiro do Sul.

It was finally named as a new genus and species by Cesar Leandro Schultz, Max Cardoso Langer and Felipe Chinaglia Montefeltro in 2016 as B. mariantensis.

A phylogenetic analysis recovered it in an advanced position with the Stenaulorhynchinae, as the sister taxon of Stenaulorhynchus stockleyi from the late Anisian of Manda beds, Tanzania.