Middle-Late Devonian Vertebrates of Antarctica

这项研究将对鲨鱼、鱼类和四肢动物的关系和历史提供新的见解。理解这些关系构成了基础科学和应用科学的支柱，因为鱼类通常是人类特征和疾病的模型。这些关系的一些主要证据来自3.8亿年前岩石中的化石，这些岩石最初是作为古代河流和溪流沉积的。由于这种类型和年代的岩石大量暴露在南极洲的许多干燥山谷和山脉中，对这些地区的调查为可能产生广泛影响的发现带来了特殊的希望。野外工作将包括地质测绘和岩石评估，并对它们可能持有的化石进行详细的勘察。化石的发现构成了科学研究方法和结果公开传播的支柱--这些研究将被用作多层次培训学生的工具，以及与更广泛的非科学公民基础的科学交流。中泥盆世(3.9亿-3.55亿年前)脊椎动物和沉积环境的发现、描述和分析为生命和地球历史上关键时期出现新的解剖结构、动物群和栖息地提供了重要数据。这一时期的生物创新包括淡水鱼的早期进化、主要脊椎动物群体(如鲨鱼、裂片和鳍鱼、四足动物)的起源，以及非海洋生态系统的扩展和细化。因此，扩大我们对中、晚泥盆世脊椎动物多样性的认识，将为脊椎动物主要类群之间的关系、最终使四足动物入侵陆地的新奇生物的集合、鲨鱼及其近亲的起源和早期进化，以及非海洋生态系统的总体组装和扩张提供新的证据。南极洲的阿兹特克粉砂岩(中-晚泥盆世；吉韦特-弗拉斯期)具有产生这些事件的新的古生物学证据并阐明它们发生的时间、生态和地理背景的特殊潜力。在已知的暴露范围内，它基本上是化石，这在世界上任何地方的中晚泥盆世非海相岩石中都是罕见的。此外，阿兹特克粉砂岩中出露了大量细粒曲流河沉积，被认为是发现保存完好的泥盆纪鱼类的重要场所，包括茎四足动物及其近亲。鉴于阿兹特克粉砂岩的化石性质极其丰富，仅从部分物质中发现了大量的分类群，而且还有大量有希望的暴露工作有待进行，因此，一项专门的勘察、收集和研究工作旨在恢复重要的新化石物质，并将其埋藏在地层和沉积学背景中。这项研究的第一个主要目标是恢复、制备和描述中、晚泥盆世化石类群。随后对化石组合的系统发育亲缘关系、化石产状和地层位置的调查将使生物多样性的局部和全球比较成为可能。这些分析将提供以下信息：1)颌类脊椎动物更高层次的系统发育假说；2)中、晚泥盆世鱼类分布的生物地层学和生物地理分析；3)陆地和淡水栖息地详述的古生物学调查。更广泛的影响源于古生物学和南极探险科学作为具有强大叙事的教育工具的用途。具体目标包括与当地城市中学建立联系(利用已建立的关系扩大参与)以及大学和研究生培训。更广泛地向公众传播知识是与国家和国际媒体(印刷、电视、互联网)不断互动的直接产物。

This research will provide new insights into the relationships and history of sharks, fish and limbed animals. Understanding these relationships forms the backbone for both basic and applied science because fish often serve as models of human traits and diseases. Some of the main lines of evidence for these relationships come from fossils in rocks over 380 million years old that were originally deposited as ancient rivers and streams. Because rocks of this type and age are abundantly exposed along a number of the dry valleys and mountains of Antarctica, the investigation of these areas holds exceptional promise for discoveries that can have a broad impact. The fieldwork will involve geological mapping and assessment of the rocks with detailed reconnaissance for the fossils that they may hold. Fossil discoveries form the backbone for public communication of the methods and results of scientific research-- these studies will be used as vehicles for training of students at multiple levels as well as communication of science to the broader non-science citizen base.The discovery, description, and analysis of Middle to Late Devonian (390-355 Million years ago) vertebrates and depositional environments provide important data on the emergence of novel anatomical structures, faunas, and habitats during a critical interval in the history of life and earth. Biological innovation during this time includes the early evolution of freshwater fish, the origins of major groups of vertebrates (e.g., sharks, lobe and ray-finned fish, tetrapods), and the expansion and elaboration of non-marine ecosystems. Accordingly, expanding our knowledge of vertebrate diversity during the Middle and Late Devonian will provide new evidence on the relationships of the major groups of vertebrates, the assembly of novelties that ultimately enabled tetrapods to invade land, the origin and early evolution of sharks and their relatives, and the assembly and expansion of non-marine ecosystems generally. The Aztec Siltstone of Antarctica Middle-Late Devonian; Givetian-Frasnian Stages) has exceptional potential to produce new paleontological evidence of these events and to illuminate the temporal, ecological, and geographic context in which they occurred. It is essentially fossiliferous throughout its known exposure range, something that is rare for Middle-Late Devonian non-marine rocks anywhere in the world. In addition, fine-grained meandering stream deposits are abundantly exposed in the Aztec Siltstone and are recognized as an important locus for the discovery of well-preserved Devonian fish, including stem tetrapods and their relatives. Given the exceedingly fossiliferous nature of the Aztec Siltstone, the large number of taxa known only from partial material, and the amount of promising exposure yet to be worked, a dedicated reconnaissance, collection, and research effort is designed to recover important new fossil material and embed it in a stratigraphic and sedimentological context. The first major objective of this study is the recovery, preparation, and description of Middle-Late Devonian fossil taxa. Ensuing investigation of the phylogenetic affinities, taphonomic occurrence, and stratigraphic position of fossil assemblages will allow both local and global comparisons of biotic diversity. These analyses will inform: 1) higher level phylogenetic hypotheses of jawed vertebrates, 2) biostratigraphic and biogeographic analysis of the distribution of the Middle-Late Devonian fish, and 3) paleobiological investigation of the elaboration of terrestrial and freshwater habitats. The broader impacts are derived from the utility of paleontology and Antarctic expeditionary science as educational tools with powerful narratives. Specific goals include affiliations with local urban secondary schools (using established relationships for broadening participation) and collegiate and graduate training. Wider dissemination of knowledge to the general public is a direct product of ongoing interactions with national and international media (print, television, internet).