神秘恐龍前體彌補翼龍起源空白
作者：
小柯機器人發布時間：2020/12/11 17:02:14
英國伯明罕大學Martín D. Ezcurra研究組合作取得最新進展。他們發現了神秘的恐龍前體，並彌補了翼龍起源的空白。該研究於2020年12月9日發表於《自然》雜誌。
利用最新發現的保存完好碎片顱骨（下頜，顱骨頂和腦箱）的微計算機斷層掃描以及可靠的相關顱後骨，他們證明了紫薇龍（一組壯大的、非暴力的恐龍前體）是翼龍的姊妹群，在整個骨骼上有許多類似突觸形態。這一發現大大縮短了最古老的翼龍與其近親之間的時間和形態學差距，同時也加強了翼龍屬於禽類鳥類的證據。
與翼龍增強的感覺能力有關的神經解剖學特徵已經存在於紫薇龍中，這表明這些特徵在飛行之前就已經進化了。他們的證據闡明了翼龍身體計劃的組裝的第一步，其對空中空間的徵服代表了脊椎動物進化中的顯著形態功能創新。
據了解，翼龍是第一個進化為動力飛行的脊椎動物，並且是中生代（大約在252-66百萬年前）陸地生態系統中的主要進化輻射之一，但是自19世紀以來，它們的起源一直是古生物學中一個尚未解決的謎團。這些飛行的爬行動物被認為是各種爬行動物進化枝的近親，包括恐龍的親屬，但這些形態和最古老的形態之間仍然存在較大的形態學鴻溝，上三疊紀系列翼龍仍然不清楚。
附：英文原文
Title: Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria
Author: Martn D. Ezcurra, Sterling J. Nesbitt, Mario Bronzati, Fabio Marco Dalla Vecchia, Federico L. Agnolin, Roger B. J. Benson, Federico Brissn Egli, Sergio F. Cabreira, Serjoscha W. Evers, Adriel R. Gentil, Randall B. Irmis, Agustn G. Martinelli, Fernando E. Novas, Lcio Roberto da Silva, Nathan D. Smith, Michelle R. Stocker, Alan H. Turner, Max C. Langer
Issue&Volume: 2020-12-09
Abstract: Pterosaurs were the first vertebrates to evolve powered flight1 and comprised one of the main evolutionary radiations in terrestrial ecosystems of the Mesozoic era (approximately 252–66 million years ago), but their origin has remained an unresolved enigma in palaeontology since the nineteenth century2,3,4. These flying reptiles have been hypothesized to be the close relatives of a wide variety of reptilian clades, including dinosaur relatives2,3,4,5,6,7,8, and there is still a major morphological gap between those forms and the oldest, unambiguous pterosaurs from the Upper Triassic series. Here, using recent discoveries of well-preserved cranial remains, microcomputed tomography scans of fragile skull bones (jaws, skull roofs and braincases) and reliably associated postcrania, we demonstrate that lagerpetids—a group of cursorial, non-volant dinosaur precursors—are the sister group of pterosaurs, sharing numerous synapomorphies across the entire skeleton. This finding substantially shortens the temporal and morphological gap between the oldest pterosaurs and their closest relatives and simultaneously strengthens the evidence that pterosaurs belong to the avian line of archosaurs. Neuroanatomical features related to the enhanced sensory abilities of pterosaurs9 are already present in lagerpetids, which indicates that these features evolved before flight. Our evidence illuminates the first steps of the assembly of the pterosaur body plan, whose conquest of aerial space represents a remarkable morphofunctional innovation in vertebrate evolution.
DOI: 10.1038/s41586-020-3011-4
Source: https://www.nature.com/articles/s41586-020-3011-4