Untangling the environmental from the dietary: dust does not matter

Area of Science:

• Paleontology
• Zoology
• Geology

Background:

• Dental microwear analysis is crucial for understanding diet and environment in extinct and extant species.
• The relative contributions of dietary silica (phytoliths) and environmental dust to tooth wear remain debated.
• Understanding these factors is vital for interpreting evolutionary adaptations in dentition, such as molar hypsodonty.

Purpose of the Study:

• To investigate the individual contributions of dietary silica and environmental dust to dental microwear in sheep under natural conditions.
• To determine whether environmental dust overwhelms the dietary signal in dental microwear textures.
• To clarify the role of diet versus environmental factors in shaping dental phenotypes.

Main Methods:

• Controlled feeding trials with sheep using dust-free and dust-laden grass and browse fodders.
• Dental microwear textural analysis (DMTA) to quantify tooth surface wear patterns.
• Simulation of natural feeding conditions, including dust exposure mimicking Harmattan winds.

Main Results:

• Dental microwear textures significantly differed between sheep on different diets, irrespective of dust presence.
• Browsing diets supplemented with dust showed distinct microwear patterns compared to dust-free grazing diets.
• Dietary properties were found to be a more significant determinant of dental microwear signatures than environmental dust.

Conclusions:

• Dietary composition is the primary factor influencing dental microwear patterns in sheep.
• Environmental dust does not obscure the dietary signal in dental microwear.
• These findings highlight the critical role of diet in driving dental evolution and adaptations.