摘要
Recent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group,but the presence of some of these features,such as bird-like brooding behaviours,remains contentious in non-avialan dinosaurs.Here we report the first non-avialan dinosaur fossil known to preserve an adult skeleton atop an egg clutch that contains embryonic remains.The preserved positional relationship of the adult to the clutch,coupled with the advanced growth stages of the embryos and their high estimated incubation temperatures,provides strong support for the brooding hypothesis.Furthermore,embryos in the clutch are at different developmental stages,suggesting the presence of asynchronous hatching—a derived feature even among crown-group birds—in non-avialan theropods.These findings demonstrate that the evolution of reproductive biology along bird-line archosaurs was a complex rather than a linear and incremental process,and suggest that some aspects of non-avialan theropod reproduction were unique to these dinosaurs.
近期研究证实许多鸟类特征在这一类群起源之前已递增式出现,但其中一些特征,譬如孵卵行为是否存在于非鸟恐龙当中还存在争议.本文报道了第一个成体位于含胚胎蛋窝之上的非鸟恐龙化石.保存的成体与蛋窝的位置关系、蛋窝内含有发育晚期的胚胎、胚胎的高孵化温度,为窃蛋龙孵卵假说提供了有力证据.更为重要的是,蛋窝内的胚胎处于不同发育阶段,表明窃蛋龙类已经具备了异步孵化这种现生鸟类里较为进步的孵化方式.这些发现证实了主龙类向鸟类演化的支系在生殖生物学上的演化是一个复杂过程,并非一个线性、渐变的过程.非鸟恐龙的某些生殖行为可能是自己所独有的.
作者
Shundong Bi
Romain Amiot
Claire Peyre de Fabrègues
Michael Pittman
Matthew C.Lamanna
Yilun Yu
Congyu Yu
Tzuruei Yang
Shukang Zhang
Qi Zhao
Xing Xu
毕顺东;Romain Amiot;Claire Peyre de Fabrègues;Michael Pittman;Matthew CLamanna;余逸伦;余琮煜;杨子睿;张蜀康;赵祺;徐星(Centre for Vertebrate Evolutionary Biology,Institute of Palaeontology,Yunnan University,Kunming 650091,China;Department of Biology,Indiana University of Pennsylvania,Indiana,PA 15705,USA;Univ Lyon,Univ Lyon 1,ENSL,CNRS,LGL-TPE,Villeurbanne,F-69622,France;Vertebrate Palaeontology Laboratory,Division of Earth and Planetary Science,The University of Hong Kong,Hong Kong,China;Section of Vertebrate Paleontology,Carnegie Museum of Natural History,Pittsburgh,PA 15213,USA;Yuanpei College,Peking University,Beijing 100871,China;Division of Paleontology,American Museum of Natural History,New York,NY 10024,USA;Key Laboratory of Vertebrate Evolution and Human Origins,Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China;Center for Excellence in Life and Paleoenvironment,Chinese Academy of Sciences,Beijing 100044,China)
基金
supported by the Double First-Class Joint Program of Yunnan Science and Technology Department and Yunnan University (2018FY001-005)
the China-Myanmar Joint Laboratory for Ecological and Environmental Conservation
the University of Hong Kong Faculty of Science RAE Improvement Fund
supported by the CNRS Program INSU INTERRVIE
the National Natural Science Foundation of China(41688103)。
