Ferrisaurus sustutensis is a relatively small ceratopsian from the Leptoceratopsidae family. It would have likely been a quadrupedal dinosaur (or rarely bipedal), a rotund body, and a thick tail. While its front legs were technically longer than the back ones, because of their positioning on the body, the front legs would have looked shorter. On its head it would have had a toothed beak, and a frill at the back of its head.
The holotype of Ferrisaurus was discovered in 1971 by Kenny Flyborg Larsen, a geologist searching for radioactive materials along a route where a railway was being constructed. He discovered the fossils because they were giving off enough radiation to be detected by his surveying instruments. Kenny kept the fossils to himself until 2004, when they were donated to Dalhousie University in Nova Scotia. The fossils were then acquired by the Royal British Columbia Museum in 2006. While the original map of the locality was lost in the ensuing years, interviews between Kenny Larsen and Victoria Arbour helped determine the most likely site of the original discovery.
The specimen was first described in 2008 by Victoria M. Arbour and Milton C. Graves, and was determined to be an unknown ornithischian. In a new research paper in 2019, Victoria M. Arbour and David C. Evans re-examined the specimen and confirmed it to be a new dinosaur.
The holotype consists of only a few bones: the front shoulder bones, left-front leg, left-rear leg, and part of the left-rear foot. There are no paratypes, so the overall size and shape of Ferrisaurus is inferred from the other members of the Leptoceratopsidae family.
Ferrisaurus was compared against other specimens in multiple dinosaur families; because of the shape of the foot bones, and sizes of the front and back legs, Ferrisaurus was determined to fit best within the Leptoceratopsidae family. While a similar family to the more famous Triceratops, the Leptoceratopsidae family of dinosaurs are smaller, lack horns, and are more basal overall.
The age of the fossils was found by the discovery of a fossilized pollen, Pseudoaquilapollenites bertillonites, in the surrounding rock. This was used as a marker taxon to determine the age of the specimen to be around 68.2 to 67.2 million years old.
Because of the diets of other dinosaurs within the same family, Ferrisaurus was determined to be herbivorous.
Ferrisaurus translates to "iron lizard", because the specimen was discovered along a rail line that was under construction (possibly because trains used to be referred to as "iron horses"). Sustutensis refers to the fact that the specimen was discovered along the Sustut River in the Sustut Basin area of British Columbia.