Three-Dimensional Reconstruction of Cephalopod Beaks: A 3D Modeling Workflow Combining Prism-Assisted Photogrammetry...

Cephalopod beaks contain rich ecological information, but their small size and sensitivity to dehydration make accurate three-dimensional (3D) reconstruction challenging. We describe a validated workflow that integrates prism-assisted photogrammetry, digital sculpting, and micro-CT validation to produce accurate 3D models of cephalopod beaks. Using the upper beak of Sepia pharaonis as a case study, a prism-reflection imaging system simultaneously captured five isometric views in a single photograph, reducing acquisition time to under 1 min. Hierarchical cluster analysis demonstrated nearly 100% species-level discrimination between S. pharaonis and Sepioteuthis lessoniana, with digital models, 3D-printed replicas, and original specimens converging at fine resolution. Digital model measurements deviated from micro-CT reference values by < 2% for linear dimensions and < 3° for angular measurements, with coefficients of variation of 3.5%-5.7% across morphological parameters. This cost-effective and portable approach removes the technical bottleneck limiting large-scale beak-based ecological analyses, enabling applications in population structure inference, diet reconstruction, and demographic modeling.