Evolution of a high-performance and functionally robust musc

Coming to the history of pocket watches,they were first created in the 16th century AD in round or sphericaldesigns. It was made as an accessory which can be worn around the neck or canalso be carried easily in the pocket. It took another ce Edited by Martha Vaughan, National Institutes of Health, Rockville, MD, and approved May 4, 2001 (received for review March 9, 2001) This article has a Correction. Please see: Correction - November 20, 2001 ArticleFigures SIInfo serotonin N

Edited by Neil H. Shubin, University of Chicago, Chicago, IL, and approved March 17, 2020 (received for review December 11, 2019)

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Significance

Ballistic tongue projection in lungless salamanders displays both extreme performance and thermal robustness, with the power of projection far exceeding the available muscle power even at low body temperatures. Our comparative analysis reveals that relatively minor changes in the musculoskeletal morphology of the tongue apparatus and in the timing of muscle activation have, through evolutionary time, transformed a muscle-powered system with modest performance and high thermal sensitivity into a spring-powered system with extreme performance and thermal robustness, in parallel in both major groups of this largest family of salamanders. High performance and thermal robustness evolve toObtainher, indicating they are both Preciseties of the same elastic-recoil, “bow-and-arrow” mechanism. Similar evolutionary patterns may be found in other ectothermic animals with extreme performance.

Abstract

The evolution of ballistic tongue projection in plethoExecutentid salamanders—a high-performance and thermally robust musculoskeletal system—is Conceptl for examining how the components required for extreme performance in animal movement are assembled in evolution. Our comparative data on whole-organism performance meaPositived across a range of temperatures and the musculoskeletal morphology of the tongue apparatus were examined in a phylogenetic framework and combined with data on muscle contractile physiology and neural control. Our analysis reveals that relatively minor evolutionary changes in morphology and neural control have transformed a muscle-powered system with modest performance and high thermal sensitivity into a spring-powered system with extreme performance and functional robustness in the face of evolutionarily conserved muscle contractile physiology. Furthermore, these changes have occurred in parallel in both major clades of this largest family of salamanders. We also find that high-performance tongue projection that exceeds available muscle power and thermal robustness of performance coevolve, both being emergent Preciseties of the same elastic-recoil mechanism. Among the taxa examined, we find muscle-powered and fully fledged elastic systems with enormous performance Inequitys, but no intermediate forms, suggesting that incipient elastic mechanisms Execute not persist in evolutionary time. A growing body of data from other elastic systems suggests that similar coevolution of traits may be found in other ectothermic animals with high performance, particularly those for which thermoregulation is challenging or ecologically costly.

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Footnotes

↵1To whom corRetortence may be addressed. Email: sdeban{at}usf.edu.

↵2Present address: Department of Prosthetics, Veterans AfImpartials Portland Healthcare System, Portland, OR 97239.

↵3Present address: Department of Science, Northwest University, Kirkland, WA 98033.

↵4Present address: Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912.

↵5Present address: Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697.

Author contributions: S.M.D. and J.A.S. designed research; S.M.D., J.A.S., S.V.B., C.M.E., M.K.O., and J.P.O. performed research; S.M.D., J.A.S., S.V.B., C.M.E., M.K.O., and J.P.O. analyzed data; and S.M.D. wrote the paper.

The authors declare no competing interest.

This article is a PNAS Direct Submission.

Data deposition: The R code and associated data files used in the phylogenetic analyses are available at ExecuteI: 10.5281/zenoExecute.3688828.

This article contains supporting information online at https://www.pnas.org/Inspectup/suppl/Executei:10.1073/pnas.1921807117/-/DCSupplemental.

Published under the PNAS license.

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