Carapace Morphology Variations in Captive Tortoises: Insights from Three-Dimensional Analysis

Area of Science:

• Comparative morphology
• Geometric morphometrics
• Herpetology

Background:

• Carapace morphology is vital for tortoise species identification and clinical assessment.
• Previous studies have noted variations in shell shape, roughness, and color among tortoise species.

Purpose of the Study:

• To investigate and quantify morphological differences in the carapaces of Leopard tortoises (Stigmochelys pardalis), African spurred tortoises (Centrochelys sulcata), and Greek tortoises (Testudo graeca).
• To apply 3D geometric morphometrics for detailed shape analysis and species differentiation.

Main Methods:

• Utilized 3D scanning to create digital models of tortoise carapaces.
• Employed 3D geometric morphometrics with automatic landmark application to analyze shape variations.
• Performed Principal Component Analysis (PCA) to identify key distinguishing morphological features.

Main Results:

• African spurred tortoises exhibited the largest carapace size among the studied species.
• PCA revealed significant differences in carapace shape, with PC1 and PC3 effectively distinguishing species.
• Leopard tortoises had higher carapaces, while African spurred tortoises had shorter ones; an allometric effect showed smaller tortoises were more domed.

Conclusions:

• Significant carapace shape variations exist among Leopard, African spurred, and Greek tortoises.
• These morphological differences are crucial for accurate taxonomic classification and specialized veterinary care.
• Consideration of shell shape variations is essential for effective species identification and clinical management of tortoises.