Middle-Late Devonian Vertebrates of Antarctica

这项研究将为鲨鱼、鱼类和四肢动物的关系和历史提供新的见解。了解这些关系是基础科学和应用科学的基础，因为鱼类经常被用作人类特征和疾病的模型。这些关系的一些主要证据来自于3.8亿年前的岩石化石，这些化石最初是作为古代河流和小溪沉积的。由于这种类型和年龄的岩石在南极洲的许多干山谷和山脉中大量暴露，对这些地区的调查有可能发现具有广泛影响的发现。野外工作包括对岩石进行地质测绘和评估，并对岩石中可能含有的化石进行详细侦察。化石发现构成了科学研究方法和结果的公共传播的支柱——这些研究将被用作培养多层次学生的工具，以及向更广泛的非科学公民基础传播科学的工具。中-晚泥盆世（3.9 - 3.55亿年前）脊椎动物和沉积环境的发现、描述和分析，为研究生命和地球历史上一个关键时期出现的新的解剖结构、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，主要脊椎动物群体的起源（如鲨鱼、叶鳍和鳍鱼、四足动物），以及非海洋生态系统的扩展和完善。因此，扩大我们对泥盆纪中晚期脊椎动物多样性的认识，将为以下方面提供新的证据：主要脊椎动物类群之间的关系、最终使四足动物能够入侵陆地的新物种的集合、鲨鱼及其近亲的起源和早期进化，以及一般非海洋生态系统的集合和扩展。南极中晚泥盆世阿兹特克粉砂岩；吉田-弗拉斯阶段（gitian - frasnian Stages）具有非凡的潜力，可以为这些事件提供新的古生物学证据，并阐明它们发生的时间、生态和地理背景。在已知的暴露范围内，它基本上都是化石，这在世界上任何地方的中晚期泥盆纪非海相岩石中都是罕见的。此外，细粒曲流沉积物在阿兹特克粉砂岩中大量暴露，被认为是发现保存完好的泥盆纪鱼类（包括茎四足动物及其亲属）的重要地点。考虑到阿兹特克粉砂岩极具化石性质，大量的分类群仅从部分材料中得知，以及大量有希望的暴露尚待研究，我们设计了专门的侦察、收集和研究工作，以恢复重要的新化石材料，并将其纳入地层学和沉积学背景。本研究的第一个主要目的是恢复、准备和描述中晚泥盆世化石分类群。随后对化石组合的系统发育亲缘关系、地层学分布和地层位置的调查将使当地和全球生物多样性的比较成为可能。这些分析将有助于：1)对有颌脊椎动物的更高层次的系统发育假设，2)对中晚泥盆世鱼类分布的生物地层学和生物地理学分析，以及3)对陆地和淡水栖息地的详细阐述的古生物学调查。更广泛的影响来自于古生物学和南极探险科学作为有力叙事的教育工具的效用。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。向公众广泛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).