About the Authors
Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas, United States of America
The authors have declared that no competing interests exist.
Hand-prepared skulls: JCO. Analyzed the data: JCO CJB. Contributed reagents/materials/analysis tools: JCO CJB. Wrote the paper: JCO CJB. Conceived and designed the experiments: JCO CJB. Analyzed the data: JCO CJB. Wrote the paper: JCO CJB.