An Enterprise in 3‐D Printed Smilodon fatalis Mandible Reconstruction: Experimentation Where No Fossil or Cast Has Gone Before

Abstract

Introduction and objectiveSmilodon fatalis went extinct approximately 10,000 years ago. During the fossilization process, changes occurred, including shrinkage, deformation, and misalignment. With no modern analog, studying how S. fatalis killed its prey, used its canines, and what bite force may have been exerted requires an accurate skull. 3‐D printing is a new way to manipulate, explore, and study fossils, in this case, the mandible of S. fatalis.Materials and methodsOur work uses modern techniques, specifically a 3‐D scanner, a 3‐D printer, and thermal plastic polyester, to accurately rebuild the mandible. These tools allowed the mandible to be manipulated from the original cast size, and width to the more correct alignment by widening the mandible so that the markers we took matched all along the maxilla.ResultsThe mandible casts we studied had narrowed over time and the upper teeth and the lower teeth did not occlude. Our novel 3‐D approach eliminates taphonomic problems including deformations that are often encountered when studying S. fatalis. This experiment created a mandible in which homologous points on the maxilla and mandible aligned correctly, and permitted the carnassial teeth to occlude properly.ConclusionsOur method allows repeatable experimental manipulation. The 3‐D printed mandible we modified became wide enough to be occluded more accurately with the glenoid fossa. The important aspects include differences between the cast mandible and the 3‐D printed one, specifically the size difference; the alignment of the incisor teeth, and the alignment of the carnassial teeth.Significance/importanceThese manipulations would not be possible with real fossils due to the rarity, texture, and fragile nature of the fossil. This is also not possible with a cast as the cast is usually a preformed plasticized unit. With this 3‐D method, researchers can make multiple copies for a variety of experiments. Until now there was no way to manipulate a fossil for better placement or alignment. Our method increases the opportunity for anatomical and functional details that can be obtained by no other means. Researchers can now use this method in studying the fossils they have on hand and the result will be a better understanding of extinct animals. These 3‐D methods are a new set of tools that can revolutionize the study of not only Smilodon but also of all other fossils.