CT scans unearth anomalies in Mongolian ankylosaurid skulls

According to a study from the National Center for Biotechnology Information from April 4, the CT scans of Mongolian ankylosaurid skulls, Tarchia included, unveiled distinctive airway characteristics and unforeseen irregularities. This suggests the potential presence of chronic osteoproliferation linked to sinus infections or trauma, highlighting the significance of CT scanning in the study of fossils. 

During the study, researchers conducted CT scans on the skulls of Mongolian ankylosaurids, including Shamosaurus, Tarchia, and Saichania, to gain insights into their internal structure. Notably, CT imaging of the Tarchia skull uncovered differences in internal anatomy when compared to known Campanian North American species, particularly in the airway morphology. Furthermore, unexpected anomalies were identified within the airway and sinuses, including mineralized concretions of various sizes.

The anomalies encompassed multiple mineralized concretions within the airway and sinuses, according to the report, with the largest positioned asymmetrically in the right nasal cavity near the supraorbitals. This concretion exhibited a distinct ovoid shape that tapered caudally and was partially encased within a hemispherical, trabeculated osseous proliferation known as a sinus exostosis. Adjacent to the exostosis was a subcircular transosseous defect in the prefrontal region of the skull roof, partially filled with ossified material, sharing architectural features with the larger exostosis. Irregularities were also observed on the internal and external surfaces of the cranial vault.

The study said that the radiologic features of the hemicircumferential exostosis suggested a potential chronic osteoproliferation in response to an ongoing inflammatory reaction to a sinus infection or, in combination with the unilateral transosseous defect, a traumatically introduced infection that could have had severe consequences. This study highlights the value of employing CT scanning to examine fossil vertebrate specimens, particularly in uncovering substantial internal lesions within the skulls that might otherwise remain undetectable.

The National Center for Biotechnology Information: Tatiana Tumanova, et al. A potentially fatal cranial pathology in a specimen of Tarchia. PubMed (4 April 2023). DOI: https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.25205