A functional explanation for denticulation in theropod dinosaur teeth

Area of Science:

• Paleontology
• Functional Morphology
• Biomechanics

Background:

• Theropod dinosaur teeth, specifically ziphodont types, exhibit varied serration (denticulation) patterns.
• Understanding these patterns can reveal functional insights into feeding behaviors.

Purpose of the Study:

• To test the hypothesis that denticles are absent in areas of theropod teeth that do not contact the substrate during feeding.
• To establish a relationship between the extent of tooth denticulation and the "dead-space" (non-contact area).

Main Methods:

• Analysis of 235 isolated and in situ theropod teeth using photographic measurements.
• Application of Euclidean and geometric morphometric methods.
• Development of a functional model predicting tooth movement direction based on tip curvature.

Main Results:

• Mesial tooth margins are typically partially denticulated, while distal margins are fully denticulated.
• Curved teeth exhibit larger dead-spaces and reduced mesial denticulation; straighter teeth are more symmetrically denticulated.
• Tooth curvature increases with distal positioning, correlating with jaw hinge proximity.

Conclusions:

• Denticulation patterns in theropod teeth suggest a distally directed puncture mechanism for substrate modification, comparable to modern animals.
• The "dead-space" is a primary determinant of mesial denticulation extent, dictated by substrate contact.
• While generally consistent across taxa, Troodontidae display exceptionally pronounced mesial denticulation.