Cranial functional specialisation for strength precedes morphological evolution in Oviraptorosauria

Area of Science:

• Paleontology
• Biomechanics
• Evolutionary Biology

Background:

• Oviraptorosaurians, particularly oviraptorids, possessed unique, pneumatized, toothless beaks adapted for herbivorous to omnivorous diets.
• Previous interpretations suggested these beaks provided a powerful bite, but their mechanical resistance was not fully understood.

Purpose of the Study:

• To investigate the mechanical stress resistance of oviraptorid crania compared to other theropods.
• To determine the evolutionary origin of enhanced cranial biomechanics within Oviraptorosauria.

Main Methods:

• Construction of digital 3D cranial models for Incisivosaurus gauthieri, Citipati osmolskae, Conchoraptor gracilis, and Khaan mckennai.
• Finite element analysis (FEA) to assess cranial strength.
• Bite modeling using estimated muscle forces.

Main Results:

• Oviraptorosaurian crania exhibited greater strength than other herbivorous theropods (Erlikosaurus, Ornithomimus) and were comparable to Allosaurus.
• Cranial biomechanics of Incisivosaurus aligned with oviraptorids, suggesting early strengthening in Oviraptorosauria.
• Oviraptorid crania operated near structural safety limits, with low beak stresses indicating a specialized feeding function for the rhamphotheca.

Conclusions:

• Enhanced cranial biomechanics were established early in Oviraptorosauria, predating specialized oviraptorid cranial morphology.
• The rhamphotheca in oviraptorids likely served as a distinct feeding tool rather than solely for stress reduction.