The axial skeleton of Bagualia alba (Dinosauria: Eusauropoda) from the Early Jurassic of Patagonia

IF 2 4区地球科学 Q1 Earth and Planetary Sciences

Palaeontologia Electronica Pub Date : 2021-01-01 DOI:10.26879/1176

K. Gómez, J. Carballido, D. Pol

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引用次数: 4

Abstract

Sauropod dinosaurs were the dominant large-bodied herbivores in many Mesozoic terrestrial ecosystems. Such predominance took place after a faunal replacement event linked to a global environmental change during the Early Jurassic (Pliensbachian–Toarcian), when the smaller basal sauropodomorphs were replaced by giant forms in the subclade Eusauropoda. Two main characteristics of this latter group are large body size (exceeding 10 tons) and a remarkably long neck. New data is presented on the axial anatomy of one of the earliest known eusauropods, Bagualia alba from the Toarcian levels of the Cañadón Asfalto Formation (Chubut Province, Argentina), which bear on the origins of these characteristics. Optimizing relevant axial characters on sauropodomorph phylogeny highlights important changes in cervical anatomy in the evolution of Sauropoda: a greater elongation of the neck due to both an increase in the vertebral count and the elongation of each cervical vertebra, and the appearance of pneumatic structures, first on the external surface (e.g., pleurocoels, laminae within the pleurocoels, accessory laminae of the neural arch) and subsequently invading the internal body of the vertebrae. These two changes have been considered essentials for body mass increase in Eusauropoda. The Toarcian age of Bagualia indicates that several important modifications in the axial skeleton and especially the neck occurred early in eusauropod evolution. These modifications are of ecomorphological importance and likely influenced the success of the eusauropods during the climatic changes surrounding the Pliensbachian–Toarcian crisis. Kevin Leonel Gomez. Consejo Nacional de Investigaciones Científicas y Técnicas, Museo Paleontológico Egidio Feruglio, Fontana 140, 9100, Trelew, Argentina. kgomez@mef.org.ar Jose Luis Carballido. Consejo Nacional de Investigaciones Científicas y Técnicas, Museo Paleontológico Egidio Feruglio, Fontana 140, 9100, Trelew, Argentina. jcarballido@mef.org.ar Diego Pol. Consejo Nacional de Investigaciones Científicas y Técnicas, Museo Paleontológico Egidio Feruglio, Fontana 140, 9100, Trelew, Argentina. dpol@mef.org.ar

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巴塔哥尼亚早侏罗世巴古利亚的轴向骨架(恐龙:真蜥足目)

在许多中生代陆地生态系统中，蜥脚类恐龙是主要的大型食草动物。这种优势是在早侏罗世(Pliensbachian-Toarcian)与全球环境变化有关的动物替换事件之后发生的，当时较小的基础蜥脚类被亚分支真蜥足类的巨大形式所取代。后者的两个主要特征是巨大的体型(超过10吨)和非常长的脖子。关于已知最早的真蜥脚类动物之一，来自Cañadón Asfalto组(Chubut省，阿根廷)Toarcian层的Bagualia alba的轴向解剖，提出了新的数据，这些数据与这些特征的起源有关。优化蜥脚类动物系统发育的相关轴向特征，凸显了蜥脚类动物进化过程中颈椎解剖学的重要变化:由于椎体数量的增加和每个颈椎的伸长，颈部的更大伸长，以及气动结构的出现，首先在外表面(例如，胸膜腔、胸膜腔内的椎板、神经弓的副椎板)，随后侵入椎体内部。这两种变化被认为是真爪足类动物体重增加的必要因素。巴瓜利亚的托瓦西亚时代表明，在真蜥脚类动物进化的早期，轴向骨骼，特别是颈部发生了一些重要的变化。这些变化在生态形态学上具有重要意义，并可能影响了在pliensbach - toarcian危机期间气候变化的真蜥脚类动物的成功。凯文·莱昂内尔·戈麦斯。国家调查委员会Científicas y tacimnicas, Paleontológico Egidio Feruglio博物馆，Fontana 144,9100，阿根廷Trelew。kgomez@mef.org.ar何塞·路易斯·卡巴利多。国家调查委员会Científicas y tacimnicas, Paleontológico Egidio Feruglio博物馆，Fontana 144,9100，阿根廷Trelew。jcarballido@mef.org.ar迭戈·波尔。国家调查委员会Científicas y tacimnicas, Paleontológico Egidio Feruglio博物馆，Fontana 144,9100，阿根廷Trelew。dpol@mef.org.ar

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来源期刊

Palaeontologia Electronica 地学-古生物学

CiteScore

3.60

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： Founded in 1997, Palaeontologia Electronica (PE) is the longest running open-access, peer-reviewed electronic journal and covers all aspects of palaeontology. PE uses an external double-blind peer review system for all manuscripts. Copyright of scientific papers is held by one of the three sponsoring professional societies at the author''s choice. Reviews, commentaries, and other material is placed in the public domain. PE papers comply with regulations for taxonomic nomenclature established in the International Code of Zoological Nomenclature and the International Code of Nomenclature for Algae, Fungi, and Plants.