Ecological Inference From Isolated Vertebrae: Evaluating Functional Signal Across the Carnivoran Spine

Area of Science:

• Vertebrate paleontology
• Functional morphology
• Paleoecology

Background:

• Reconstructing extinct species' ecology is vital but hindered by incomplete fossils.
• Vertebrae are often overlooked despite being common fossil elements.
• The utility of isolated vertebrae for ecological inference remains debated.

Purpose of the Study:

• To assess the predictive power of vertebral morphology for running speed and hunting mode in extant carnivorans.
• To determine if individual vertebrae or vertebral combinations provide stronger ecological signals.
• To apply this framework to infer the ecology of the extinct dire wolf (Aenocyon dirus).

Main Methods:

• Utilized 3D geometric morphometrics on 10 presacral vertebrae from diverse extant carnivorans.
• Evaluated predictive power of individual vertebrae, regional groups (cervical, thoracic, lumbar), and multi-element combinations.
• Applied findings to fossil vertebrae of Aenocyon dirus.

Main Results:

• Certain vertebrae, particularly the first thoracic and lumbar, independently predict ecological traits effectively.
• Combining multiple vertebrae often dilutes the ecological signal.
• Aenocyon dirus exhibits a mosaic of vertebral signals, suggesting a complex niche involving predation and scavenging.

Conclusions:

• Isolated vertebrae, strategically chosen, can be powerful tools for ecological inference in paleontology.
• Vertebral regions should be analyzed independently due to differing functional roles.
• Vertebral morphology provides crucial insights into extinct carnivoran behavior, especially with fragmentary remains.