Dinosaur skull geometry does not follow functional optimization trends but facilitates adaptability.

Area of Science:

• Paleontology
• Biomechanics
• Evolutionary Biology

Background:

• Dinosaur skulls display diverse shapes and sizes, but their geometric and biomechanical properties remain poorly quantified.
• The evolutionary trends of dinosaur skull geometry concerning feeding performance and structural integrity are not well understood.

Purpose of the Study:

• To biomechanically quantify dinosaur skull geometry, focusing on the rostrum, orbital region, and braincase.
• To investigate whether dinosaur skull evolution aimed for functional optimality or a compromise between different functions.
• To explore the role of skull proportions in shaping dinosaur evolution, particularly during the transition to birds.

Main Methods:

• Utilized morphometric analyses to quantify skull geometry.
• Employed theoretical morphospaces to analyze skull proportion patterns.
• Applied biomechanical modeling to assess functional implications of skull shapes.

Main Results:

• Dinosaur skull proportions exhibited a narrowly constrained evolutionary pattern.
• The rostrum demonstrated the greatest variability and plasticity compared to other skull regions.
• Skull evolution did not lead to functional optimality but rather a 'Goldilocks' zone balancing multiple functions.

Conclusions:

• Dinosaur skull evolution prioritized a balance of functions over peak performance in any single area.
• The rostrum's adaptability was crucial, potentially facilitating environmental interaction and adaptation.
• Rostral plasticity may have been particularly significant for the evolution of birds from non-avian dinosaurs, compensating for lost forelimb functions.