巴西圣玛利亚联邦大学Mller, Rodrigo T. 课题组提出，新爬行动物显示恐龙和翼龙从不同的前身中进化而来。相关论文于2023年8月16日发表于国际顶尖学术期刊《自然》杂志上。

研究团队展示了一个保存完好兔蜥的部分骨骼化石(三叠纪晚期，巴西)。这提供了对这些前体之一的头骨和生态的更全面的观察。它的头骨有一个锋利的，像猛禽一样的喙，比恐龙早了大约 8,000 万年，还有一只长着长而锋利爪子的大手，这坚定地证明了这些前身谱系中强制性四足动物的消失。

结合新物种与其他恐龙和翼龙前体的解剖信息，表明前体的形态差异类似于三叠纪翼龙，超过三叠纪恐龙。因此，翼龙和恐龙的“成功”是在更广泛的生态形态变异中差异生存的结果。研究结果表明，鸟足类的形态多样性不仅仅是在恐龙和翼龙起源之后，而是在早期分化的谱系中开始繁荣。

据介绍，在中生代的大部分时间里，恐龙和翼龙具有显著的多样性和差异性。在它们起源后不久，这些爬行动物分化成许多长寿的谱系，进化出前所未有的生态(例如，飞行、大型食草动物形式)，并遍布泛古大陆。最近发现的恐龙和翼龙的前身表明，这些动物物种繁多，但这些前身几乎没有保存完好的头骨、手和相关骨骼。

附：英文原文

Title: New reptile shows dinosaurs and pterosaurs evolved among diverse precursors

Author: Mller, Rodrigo T., Ezcurra, Martn D., Garcia, Mauricio S., Agnoln, Federico L., Stocker, Michelle R., Novas, Fernando E., Soares, Marina B., Kellner, Alexander W. A., Nesbitt, Sterling J.

Issue&Volume: 2023-08-16

Abstract: Dinosaurs and pterosaurs have remarkable diversity and disparity through most of the Mesozoic Era. Soon after their origins, these reptiles diversified into a number of long-lived lineages, evolved unprecedented ecologies (for example, flying, large herbivorous forms) and spread across Pangaea. Recent discoveries of dinosaur and pterosaur precursors demonstrated that these animals were also speciose and widespread, but those precursors have few if any well-preserved skulls, hands and associated skeletons. Here we present a well-preserved partial skeleton (Upper Triassic, Brazil) of the new lagerpetid Venetoraptor gassenae gen. et sp. nov. that offers a more comprehensive look into the skull and ecology of one of these precursors. Its skull has a sharp, raptorial-like beak, preceding that of dinosaurs by around 80million years, and a large hand with long, trenchant claws that firmly establishes the loss of obligatory quadrupedalism in these precursor lineages. Combining anatomical information of the new species with other dinosaur and pterosaur precursors shows that morphological disparity of precursors resembles that of Triassic pterosaurs and exceeds that of Triassic dinosaurs. Thus, the ‘success’ of pterosaurs and dinosaurs was a result of differential survival among a broader pool of ecomorphological variation. Our results show that the morphological diversity of ornithodirans started to flourish among early-diverging lineages and not only after the origins of dinosaurs and pterosaurs.

DOI: 10.1038/s41586-023-06359-z

Source: https://www.nature.com/articles/s41586-023-06359-z