Assessment of the potential of modern digital methods in morphological studies of vertebrate skeletons: A case study of the marsh frog skull Pelophylax ridibundus (Ranidae, Anura) with the development of a VR application

Abstract

The digitalization of biological collections opens new opportunities for research and education, yet the methodological accuracy of 3D modeling compared to traditional morphometrics remains insufficiently tested on small and fragile objects. This study evaluates whether optical 3D scanning can serve as a reliable alternative to conventional caliper measurements in vertebrate craniometry and demonstrates its application in an educational VR environment. Ten skulls of the marsh frog (Pelophylax ridibundus) from VolSU zoological collection were measured using three methods: digital caliper (reference method), 3D models obtained with a Range Vision optical scanner and processed in Blender, and 2D image analysis in ImageJ. Four standard craniometric parameters were compared. Pairwise comparison using Student's t-test revealed no statistically significant differences between caliper and 3D modeling for all parameters (p > 0.05), confirming their methodological equivalence. ImageJ analysis showed significant discrepancies with both contact methods for interorbital distance and skull height (p < 0.05). The mean differences across all methods ranged from 0.02 to 1.60 mm. Based on these findings, an educational VR application was developed in Unity, allowing interactive study of high-resolution 3D skull models of four vertebrate species (Yemen chameleon, grey heron, eagle owl, red-crested pochard) from the university collection. Users can manipulate models and access species information. The study demonstrates that 3D modeling is a methodologically accurate, non-destructive alternative to traditional craniometry even for small objects, while VR integration enhances digital education and broadens access to scientific collections.