Semi-aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil
Semi-aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil
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DOI：
10.1016/j.cretres.2018.04.024
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发表时间：
2018-10-01
影响因子：
2.1
通讯作者：
Sander, Martin
中科院分区：
文献类型：
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作者：
Aureliano, Tito;Ghilardi, Aline M.;Sander, Martin
众所周知，棘龙亚科与水生环境有着密切的关系，涉及多种解剖学适应。尽管如此，由于化石记录相对不完整，这组兽脚亚目动物仍然是个谜。本文通过解剖比较和古组织学分析描述了来自巴西东北部 Aptian-Albian Romualdo 组的大型部分胫骨。它具有以前仅在埃及棘龙中观察到的特征，其中包括腓骨嵴缩小和骨硬化状况。后者被认为与许多有肢脊椎动物的半水生习性相关。这里提出的结果支持巴西棘龙亚科动物早于摩洛哥棘龙数百万年就已经存在高骨致密性。此外，组织学分析表明，罗穆尔多组标本是一个年轻的亚成体，在死亡时仍在快速生长，并表明阿拉里皮盆地棘龙可能比以前认为的更大。这项工作有助于更好地了解南美棘龙的古生物学和生态学知识，并有助于填补棘龙亚科宏观进化理解的空白。最终，它还有助于进一步推进罗马尔多地层的古生态特征。 (C) 2018 Elsevier Ltd. 保留所有权利。
Spinosaurinae are known to have a strong relationship with aquatic environments, involving several anatomical adaptations. Nonetheless, this group of theropods remains enigmatic, due to the relative incompleteness of its fossil record. A large partial tibia from the Aptian-Albian Romualdo Formation, Northeast Brazil, is herein described through anatomical comparisons and paleohistological analyzes. It features characteristics previously only observed in Spinosaurus aegyptiacus, which includes a reduced fibular crest and an osteosclerotic condition. The later, a character supported as correlated with semi aquatic habits in many limbed vertebrates. The results presented here support high bone compactness being already present in Brazilian Spinosaurinae millions of years before the Moroccan Spinosaurus. Furthermore, histological analyses demonstrate the Romualdo Formation specimen was a young sub adult still growing fast by the time of its death, and suggests Araripe Basin Spinosaurinae could have grown larger than previously thought. This work contributes to a better paleobiological and ecological understanding of South American spinosaurs, and helps fill a gap in the macroevolutionary comprehension of Spinosaurinae. Ultimately, it also contributes to further advancing the paleoecological characterization of the Romualdo Formation. (C) 2018 Elsevier Ltd. All rights reserved.