Triceratops had an enormous nasal cavity — disproportionately large relative to its skull, far larger than needed for olfaction alone. The standard explanation was defensive: the bony frill and horns demanded a massive skull, and the nose simply filled the available space. No functional analysis of the nasal interior had been attempted because fossil bone preserves shape but not soft tissue, and soft tissue is where respiratory function lives.
Published in The Anatomical Record, University of Tokyo researchers used CT scans to map the internal architecture of Triceratops skulls and discovered respiratory turbinates — thin, curled bony surfaces that increase the area available for heat exchange between blood and inhaled air. More unexpectedly, they found that the main nerves and blood vessels of the snout were rerouted through the nasal cavity instead of through the jaw, the typical path in most vertebrates. The nose was not empty space. It was a thermoregulatory organ with a dedicated vascular supply.
The structural insight is about how function gets attributed after the fact. The frill-and-horns narrative provided a structural explanation for the skull's size, and once the size was explained, the nose needed no separate explanation — it was assumed to be a byproduct. The CT scans reveal that the nose had its own functional architecture, independent of the frill. The rerouted vasculature is the key evidence: you do not evolve a novel vascular path to fill dead space. The nose was not leftover from the frill. The frill and the nose were solving different problems — defense and thermoregulation — using the same skull. One explanation hid the other.