Increased sampling reveals the complex evolution of sauropod dinosaur tooth replacement rates

Area of Science:

• Paleontology
• Vertebrate Paleontology
• Dinosaur Paleobiology

Background:

• Sauropod dinosaurs, unlike most herbivores, possessed simple teeth with rapid replacement.
• Craniodental morphology in sauropods shows conservation, but tooth breadth and replacement rates vary significantly.
• Convergent evolution of narrow-crowned teeth and high replacement rates occurred independently in Titanosauria and Diplodocoidea.

Purpose of the Study:

• To investigate the evolution of tooth replacement rate and tooth breadth in sauropod dinosaurs.
• To improve understanding of sauropod paleobiology and ecological inferences through enhanced sampling.
• To analyze histological and tomographic data from Cretaceous sauropods.

Main Methods:

• Integration of histological and tomographic data to examine sauropod genera.
• Histological description of dentine and enamel for Early Cretaceous taxa (Abydosaurus and Moabosaurus).
• Ancestral state reconstruction on a time-calibrated phylogeny.

Main Results:

• Earliest macronarians and brachiosaurids retained ancestral low tooth replacement rates (2-3 months per tooth).
• Diplodocoids independently evolved significantly higher tooth replacement rates (2-5 weeks per tooth).
• Broad-crowned teeth correlate with low replacement rates; narrow-crowned teeth show variable relationships.

Conclusions:

• Sauropod tooth replacement rates evolved substantially, with high rates appearing convergently.
• Tooth morphology and replacement rate provide insights into dietary adaptations and paleobiology.
• Further research is needed to fully understand the diversity of sauropod tooth replacement strategies.