| Autor: |
Tseng ZJ; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.; Museum of Paleontology, University of California, Berkeley, CA 94720, USA.; Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA., Garcia-Lara S; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.; Museum of Paleontology, University of California, Berkeley, CA 94720, USA., Flynn JJ; Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA.; Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024, USA., Holmes E; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA., Rowe TB; Jackson School of Geological Sciences, University of Texas, Austin, TX 78712, USA., Dickson BV; Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA. |
| Abstrakt: |
The evolutionary shift from a single-element ear, multi-element jaw to a multi-element ear, single-element jaw during the transition to crown mammals marks one of the most dramatic structural transformations in vertebrates. Research on this transformation has focused on mammalian middle-ear evolution, but a mandible comprising only the dentary is equally emblematic of this evolutionary radiation. Here, we show that the remarkably diverse jaw shapes of crown mammals are coupled with surprisingly stereotyped jaw stiffness. This strength-based morphofunctional regime has a genetic basis and allowed mammalian jaws to effectively resist deformation as they radiated into highly disparate forms with markedly distinct diets. The main functional consequences for the mandible of decoupling hearing and mastication were a trade-off between higher jaw stiffness versus decreased mechanical efficiency and speed compared with non-mammals. This fundamental and consequential shift in jaw form-function underpins the ecological and taxonomic diversification of crown mammals. This article is part of the theme issue 'The mammalian skull: development, structure and function'. |
