Monoclonius (meaning "single sprout") is a dubious genus of herbivorous ceratopsian dinosaurs found in the Late Cretaceous layers of the Judith River Formation in Montana, northern US, and the uppermost rock layers of the Dinosaur Park Formation in Alberta, Canada dated to between 75 and 74.6 million years ago.
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