A Diverse Tetrapod Fauna at the Base of 'Romer's Gap'.
A Diverse Tetrapod Fauna at the Base of 'Romer's Gap'.
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DOI：
10.1371/journal.pone.0125446
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Clack J
中科院分区：
文献类型：
--
作者：
Anderson JS;Smithson T;Mansky CF;Meyer T;Clack J
最早的石炭纪（“罗默峡”）缺乏含有四足动物化石的沉积物，最近引发了一些关于近因的讨论，并提出了三种解释：环境、埋藏学和收集失败。为数不多且最早的了解这一时期的窗口之一是位于加拿大新斯科舍省汉茨波特附近埃文河沿岸霍顿布拉夫图尔奈西亚沉积物中的蓝色海滩。这个地点早已为人所知，但由于化石是在高能量环境下沉积的，它们几乎总是被分解，因此动物群尚未被详细描述。最近的密集收集揭示了材料的多样化组合，包括首次相关元素，这使得可以对当地的动物群成分进行评估。尽管无法在精细的分类水平上进行诊断，但存在足够的无源性来识别来自其他地方更完整的标本中已知的众多进化枝的代表。证据表明存在多种动物群，包括Whatcheeriids和embolomeres。以前曾将单个肱骨归因于结肠胶，但这种鉴定存在一些不确定性。其他元素表明存在仅在泥盆纪晚期才知道的类群。该地区的沉积偏差有利于来自较大个体的四足动物化石，但来自足迹和诱人的孤立骨骼的间接证据证明存在仍有待发现的小型类群。蓝色海滩的化石表明，当发现“罗默峡”动物群的窗口时，将显示出丰富的四足动物多样性，而相反的论点则表明化石记录中的这种中断是由于大气中氧气水平等外在因素造成的。他们还表明，早期四足动物群不容易分为泥盆纪和石炭纪动物群，这表明一些四足动物在泥盆纪末期灭绝事件中未受影响。
The lack of fossil tetrapod bearing deposits in the earliest Carboniferous (‘Romer’s Gap’) has provoked some recent discussions regarding the proximal cause, with three explanations being offered: environmental, taphonomic, and collection failure. One of the few, and earliest, windows into this time is the locality of Blue Beach exposed in the Tournaisian deposits at Horton Bluff lying along the Avon River near Hantsport, Nova Scotia, Canada. This locality has long been known but, because the fossils were deposited in high energy settings they are almost always disarticulated, so the fauna has not been described in detail. Recent intensive collection has revealed a diverse assemblage of material, including for the first time associated elements, which permits an evaluation of the faunal constituents at the locality. Although not diagnosable to a fine taxonomic level, sufficient apomorphies are present to identify representatives from numerous clades known from more complete specimens elsewhere. The evidence suggests a diverse fauna was present, including whatcheeriids and embolomeres. A single humerus previously had been attributed to a colosteid, but there is some uncertainty with this identification. Additional elements suggest the presence of taxa otherwise only known from the late Devonian. Depositional biases at the locality favor tetrapod fossils from larger individuals, but indirect evidence from trackways and tantalizing isolated bones evidences the presence of small taxa that remain to be discovered. The fossils from Blue Beach demonstrate that when windows into the fauna of ‘Romer’s Gap’ are found a rich diversity of tetrapods will be shown to be present, contra arguments that suggested this hiatus in the fossil record was due to extrinsic factors such as atmospheric oxygen levels. They also show that the early tetrapod fauna is not easily divisible into Devonian and Carboniferous faunas, suggesting that some tetrapods passed through the end Devonian extinction event unaffected.
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影响因子：
2.6
作者：
Clack, Jennifer A.
通讯作者：
Clack, Jennifer A.
影响因子：
64.8
作者：
Clack, JA;Ahlberg, PE;Ketcham, RA
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作者：
Boisvert, CA
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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