Chthonosaurus is an extinct genus of therocephalian therapsid from the Late Permian of Russia. It belongs to the family Akidnognathidae. The type species Chthonosaurus velocidens was named in 1955.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0