Upper Cretaceous Vertebrate Fauna at Dzharakuduk, Kyzylkum Desert, Uzbekistan: Biostratigraphy, Biogeography, and Phylogeny

这项拟议工作的主要目标是：1)继续在乌兹别克斯坦基季尔库姆沙漠的Dzharakuduk(晚白垩世，图罗尼亚？-坎帕尼亚)进行广泛的收集，2)将这些重要的收集放在全球生物地层、古生态和生物地理的背景下，3)继续对已经发现的大量收集进行描述和系统发育分析。已故的俄罗斯古生物学家列夫·A·涅索夫和学生于20世纪70年代末开始在乌兹别克斯坦基尔库姆沙漠中部的Dzharakuduk进行实地研究，1994年由Nessov和Pi继续进行，1997年由包括Pi和Pi在内的11人组成的团队继续进行。这些研究以及由此开始产生的出版物表明，该地区是分类学上最丰富的(已报告的物种超过130种)，可以说是所有欧亚大陆最重要的晚白垩世脊椎动物群之一。世界著名的戈壁沙漠中略年轻的遗址(晚白垩世、坎帕尼亚)产生了更完整的材料，但来自Dzharakuduk的更零碎的材料往往很精致，保存了相当大的解剖细节，甚至是北美晚白垩世遗址几乎不知道的完整的头骨和四肢元素。过去在Dzharakuduk进行的大规模地面收集也是在1997年进行的，但在田间季节的最后三天，对关键的生产区间进行了标记和密集的干筛。在两天半的筛选和分类中(10只哺乳动物被回收)，几乎与之前三周的所有表面收集(15只哺乳动物)相比，脊椎动物(例如哺乳动物)的标本被回收。因此，在接下来的三个野外季节，对某些Dzharakuduk遗址进行广泛的干燥筛选将是关键。Dzharakuduk悬崖包括大约200米的沉积物。Nessov认为，Dzharakuduk的脊椎动物栖息地是河流和微咸水环境的组合，由海相岩石覆盖和覆盖。下面的岩石被认为是图罗纪时代，而悬崖上方的岩石被认为是白垩纪和古近纪的最上层。在1994年我们的勘察中，在悬崖顶部发现了一个菊石(后来被确认为桑托纪)，这表明那里没有暴露出古近纪的沉积物。在我们1997年更广泛的工作中，我们发现Dzharakuduk遗址都是河流起源的，并被一系列长期但尚未确定的半平原事件所包围。下面的沉积物肯定是边缘海相，但确定年龄仍然难以捉摸。覆盖的沉积物范围从边缘海洋到完全海洋，并在暴露的顶部附近产生了非常丰富的海洋无脊椎动物动物群(80多个物种)。稍低一些的无脊椎动物也长出了数千颗鲨鱼牙齿(12-15种)。这两个动物群都需要详细的研究，但都暗示着从桑托尼亚到坎帕尼亚早期的时代。这一非常初步的分析表明，早期对Dzharakuduk大陆脊椎动物遗址的Coniacian年龄的评估可能是正确的，或者可能是稍微年轻的桑托人年龄。已经制作了产生各种微型化石的沉积物样本，但我们等待资金来准备和研究这些以及大型无脊椎动物。Dzharakuduk代表低海岸平原的河流遗址在古生态上与北美晚白垩世遗址非常相似，但与戈壁非常不同，戈壁更多是高地、干燥和风沙占优势的地区。Dzharakuduk和北美晚白垩世丰富的鱼类包括鲨鱼、两栖动物和水生海龟只表明了这种古生态相似性，但只有在获得资金以进行完整的分类、整理和动物群分析的情况下，才有可能进行更彻底的比较。除了脊椎动物和无脊椎动物的动物群分析和古生态解释之外，这项拟议工作的一个非常重要的组成部分是对选定的类群进行系统发育分析。Nessov和他的学生用俄语发表了各种较短的论文和较大的(主要是天气)目录，内容涉及脊椎动物动物群的各个方面，但对各种脊椎动物分类群的更大、更详细的研究已经开始。最近，Nessov、PI和Kielan-Jaworowska(1997)发表了第一份关于Dzharakuduk脊椎动物的专题研究报告，其中包括系统发育分析。这是对“zhelestids”的阿尔法级别分类的专题研究，以及对这些胎盘哺乳动物的系统发育分析，表明它们与它们的姊妹分类群Unulata(各种外生分类群加上现存的有蹄类、亚蹄类和鲸鱼)的关系，直到Dzharakuduk“zhelestids”大约2000万年后，才出现在K/T边界附近。根据来自Dzharakuduk的这些“zhelestids”，PI能够命名和描述哺乳动物的一个新的超级分类群--Unultom forma。拟议的拨款将允许从Dzharakuduk恢复和研究其他脊椎动物，这些脊椎动物肯定会对系统发育研究产生同样的兴趣。

9804771ArchibaldMain objectives of this proposed work are: 1) to continue extensive collecting at Dzharakuduk (Late Cretaceous, Turonian? - Campanian), Kyzylkum Desert, Uzbekistan, 2) to place these important collection in a global biostratigraphic, paleoecologic, and biogeographic context, 3) and to continue the description and phylogenetic analyses of extensive collections already recovered.Field studies at Dzharakuduk, central Kyzylkum Desert, Uzbekistan were begun in the late 1970's by the late Russian paleontologist Lev A. Nessov and students, continued by the Nessov and the PI in 1994, and by a crew of 11 persons including the PI and co-Pi in 1997. These studies, and the publications that are beginning to result from them, demonstrate that this area is the taxonomically richest (over 130+ species have been reported) and arguably one of the most important Late Cretaceous vertebrate faunas in all of Eurasia. The slightly younger sites (Late Cretaceous, Campanian) in the world-famous Gobi Desert produce more complete material, but the more fragmentary material from Dzharakuduk is often exquisite, preserving considerable anatomical detail or even whole cranial and limb elements that are almost unknown from Late Cretaceous sites in North America. The extensive surface collecting that had been conducted in the past at Dzharakuduk was also done in 1997, but key producing intervals were flagged and intensively dry screened in the last three days of the field season. Almost as many specimens of vertebrates (e.g., mammals) were recovered in two and one-half days of screening and sorting (10 mammals recovered) compared all of the previous three weeks of surface colecting (15 mammals recovered). Thus, extensive dry screening at certain Dzharakuduk sites will be of key importance during the next three field seasons.The Dzharakuduk escarpment includes about 200 meters of sediment. Nessov argued that the vertebrate-bearing sites at Dzharakuduk were a combination of fluvial and brackish-water environments, underlain and overlain by marine rocks. The underlying rocks were argued to be Turonian in age, while those above in the escarpment were thought to be uppermost Cretaceous and Paleogene. The discover during our reconnaissance in 1994 of an ammonite (later identified as Santonian in age) at the top of the escarpment demonstrated that no Paleogene sediments were exposed there. During our more extended work in 1997 it was shown that the Dzharakuduk sites are all fluvial in origin and are bracketed by a series of peneplanation events of long, but undetermined age. The underlying sediments are definitely marginal marine, but establishing an age remains elusive. The overlying sediments range from marginal marine to fully marine, and have yielded a very rich fauna of marine invertebrates (80+ species) near the top of the exposure. A slightly lower invertebrate fauna also yielded thousands of shark teeth (12-15 species). Both faunas require detailed study, but are suggestive of an age as old as Santonian to as young as early Campanian. This very preliminary analysis suggesests the earlier assessment of a Coniacian age for the continental vertebrate sites at Dzharakuduk may be correct, or a slightly younger Santonian age is possible. Samples of sediments yielding various microfossils were made, but we await funding for preparation and study of these as well as the macroinvertebrates. The fluvial sites representing low coastal plains at Dzharakuduk are very paleoecologically similar to Late Cretaceous sites in North America, but are very unlike those in the Gobi, which are much more upland, dry, and aeolian dominated. The abundance of fishes including sharks, amphibians, and aquatic turtles at both Dzharakuduk and in the Late Cretaceous of North America stronly suggest this paleoecological similarity, but more thorough comparisons will only be possible if funds are secred to permit complete sorting, curation, and faunal analyses.In addition to faunal analysis and paleoecological interpretations of the vertebrates and invertebrates , a very important component of this proposed work is phylogenetic analysis of selected taxa. A variety of shorter papers and larger, mostly synoptic catalogies have appeared (mostly) in Russian by Nessov and his students on various aspects of the vertebrate fauna, but larger, more detailed studies have begun on various vertebrate taxa. The first monographic treatment of vertebrates from Dzharakuduk including a phylogenetic analysis was recently published by Nessov, the PI, and Kielan-Jaworowska (1997). This a monographic study of the alpha-level taxonomy of "zhelestids" as well as a phylogenetic analysis of these placental mammals showing their relationships to their sister taxon Ungulata (a variety of extict taxa plus the extant ungulates, sub-ungulates, and whales), which do not appear until near the K/T boundary some 20 million years after the Dzharakuduk "zhelestids". Based on these "zhelestids" from Dzharakuduk the PI was able to name and describe a new superordinal taxon of mammals, the Ungulatomorpha. The proposed grant will permit the recovery and study of other vertebrates from Dzharakuduk that will surely be of equal interest for phylogenetic studies.