Possibilities of Virtual Paleohistology: A Comparative Study with Sauropod Dinosaurs

Paleohistology, the study of fossilized bone microstructure, is crucial for understanding the growth and life history of extinct vertebrates. Traditional methods rely on destructive thin-sectioning, limiting its application. Micro-computed tomography (μCT) offers a non-destructive alternative using X-ray, but its reliability for paleohistological analysis remains underexplored. This comparative study evaluates the effectiveness of μCT by analyzing 14 sauropod specimens representing multiple genera, ontogenetic stages, and geological formations, using μCT scanning and thin-section microscopy.

μCT successfully visualized key histological features, including vascularization, secondary osteons, and lines of arrested growth (LAGs), with a strong correspondence to thin-section data (K = 0.71–1.0). Scans of specimens under 15 mm in diameter showed all considered structured with a level of detail comparable to the thin sections. In some cases, μCT revealed features more clearly than microscopy, especially when diagenetic infilling obscured thin sections. While artifacts and noise can often be mitigated, larger specimens require scanning at greater distances, increasing voxel size and thus reducing resolution - a trade-off determined by field-of-view limitations rather than bone size. Advances in technology and reconstruction algorithms continue to improve image quality, highlighting the importance of archiving raw data for future reprocessing.

μCT’s advantages include three-dimensional visualization and the ability to study intra- and interskeletal series non-destructively. This approach preserves fossil integrity and promotes data sharing and reproducibility. Our findings validate μCT as a powerful tool for virtual paleohistology. Future directions include the standardization of protocols and integration with advanced imaging techniques and machine learning to further enhance resolution and accessibility.