In this proposed classification system, the tyrannosauroids were supposedly basal to a clade known as Bullatosauria, which was made up of the Troodontidae and the Ornithomimosauria. These two groups were purported to form a clade, because they both shared a common characteristic; which was a skull capsule. However, later on, both of these classification systems were found to be paraphyletic, or "artificial", clades.
This proposed classification system attempted to group together tyrannosauroids, Troodontidae, and Ornithomimosauria based on their shared skull capsule. However, later research revealed that this grouping was flawed and did not accurately reflect the evolutionary relationships between these groups.