科学家发现某些恐龙也能游泳—小柯机器人—科学网

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科学家发现某些恐龙也能游泳
        作者：小柯机器人 发布时间：2020/5/1 14:34:23
                 本期文章：《自然》：Online/在线发表

                  
        美国哈佛大学Stephanie E. Pierce、底特律大学Nizar Ibrahim等研究人员合作发现，兽脚亚目恐龙具有可用于水上运动的尾部。该研究于2020年4月29日在线发表于《自然》。
        据研究人员介绍，近几十年来，对非禽类恐龙的深入研究强烈表明，这些动物仅限于陆地环境。一些类群（如蜥脚类动物和鸭嘴龙）生活在水生环境中的猜想在几十年前就被放弃了。但最近有人争论说，至少一些棘龙类（白垩纪时期的大型肢体兽脚类群）是半水生的，但是这个理论在解剖学、生物力学和埋藏学方面受到了挑战，并且仍然存在争议。
       
        研究人员为恐龙中的水生推进结构提供了明确的证据，即巨型兽脚亚目棘龙（Spinosaurus aegyptiacus）。这种恐龙的尾巴具有出乎意料的独特形状，由极高的神经棘和细长的V形组成，从而形成了大型、灵活的鳍状器官，能够进行广泛的横向偏移。
       
        使用机器人拍打设备测量不同尾巴形状物理模型的起伏力，研究人员发现，棘龙的尾形在水中比陆生恐龙的尾形产生更大的推力和效率，并且这些性能指标与现存的水生脊椎动物的可比性更强，后者使用垂直扩展的尾巴在游泳时产生正向推进力。
       
        这些结果与以前针对棘龙所记录的适应水生生活方式和食鱼性饮食的一整套方法是一致的。尽管发育程度较低，但在棘龙类进化枝的其他成员中也发现了水生适应物，其出现了近全球分布，且地层范围超过5000万年，这表明恐龙大量进入了水生环境 。
       
        附：英文原文
        Title: Tail-propelled aquatic locomotion in a theropod dinosaur
        Author: Nizar Ibrahim, Simone Maganuco, Cristiano Dal Sasso, Matteo Fabbri, Marco Auditore, Gabriele Bindellini, David M. Martill, Samir Zouhri, Diego A. Mattarelli, David M. Unwin, Jasmina Wiemann, Davide Bonadonna, Ayoub Amane, Juliana Jakubczak, Ulrich Joger, George V. Lauder, Stephanie E. Pierce
        Issue&Volume: 2020-04-29
        Abstract: In recent decades, intensive research on non-avian dinosaurs has strongly suggested that these animals were restricted to terrestrial environments1. Historical proposals that some groups, such as sauropods and hadrosaurs, lived in aquatic environments2,3 were abandoned decades ago4,5,6. It has recently been argued that at least some of the spinosaurids—an unusual group of large-bodied theropods of the Cretaceous era—were semi-aquatic7,8, but this idea has been challenged on anatomical, biomechanical and taphonomic grounds, and remains controversial9,10,11. Here we present unambiguous evidence for an aquatic propulsive structure in a dinosaur, the giant theropod Spinosaurus aegyptiacus7,12. This dinosaur has a tail with an unexpected and unique shape that consists of extremely tall neural spines and elongate chevrons, which forms a large, flexible fin-like organ capable of extensive lateral excursion. Using a robotic flapping apparatus to measure undulatory forces in physical models of different tail shapes, we show that the tail shape of Spinosaurus produces greater thrust and efficiency in water than the tail shapes of terrestrial dinosaurs and that these measures of performance are more comparable to those of extant aquatic vertebrates that use vertically expanded tails to generate forward propulsion while swimming. These results are consistent with the suite of adaptations for an aquatic lifestyle and piscivorous diet that have previously been documented for Spinosaurus7,13,14. Although developed to a lesser degree, aquatic adaptations are also found in other members of the spinosaurid clade15,16, which had a near-global distribution and a stratigraphic range of more than 50 million years14, pointing to a substantial invasion of aquatic environments by dinosaurs.
        DOI: 10.1038/s41586-020-2190-3
        Source: http://www.nature.com/articles/s41586-020-2190-3
                          期刊信息
                 Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：43.07
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html

      









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