Investigation of the dinosaur fauna of the Middle Jurassic Balabansai Formation of Kyrgyzstan and insights into the evolutionary radiation and biogeography of dinosaurs in central Asia

恐龙是有史以来最成功、分布最广的陆地脊椎动物之一。它们的化石遗骸也很常见，这使它们成为探索脊椎动物进化和分布模式的理想候选者。在1.74亿至1.63亿年前的中侏罗世，许多主要的恐龙种群进化或即将形成。不幸的是，中侏罗世的恐龙化石在世界范围内非常罕见，因此关于它们的进化的知识非常不完整。此外，来自东亚的恐龙动物群可能在中侏罗世开始独立于世界其他地区演化，最终导致恐龙动物群的孤立和特有。中亚国家吉尔吉斯斯坦的巴拉班赛组可能是解决中侏罗世恐龙演化和分布模式的关键：1)该组的年代被确定为中侏罗世，2)它以含有恐龙化石的沉积物而闻名，3)它的地理位置就像现在一样，位于欧亚大陆西部和东亚之间。最近发现的两个蜥脚类恐龙和兽脚类恐龙的部分骨骼进一步证实，在这些沉积物中可能会有重要的科学发现。这一初步项目的第一个目标是记录已经发现的恐龙化石，并为后续的更大规模的项目确定新的地点。由于世界范围内缺乏足够的中侏罗世化石，每一次新的发现都将显著增加对恐龙进化和关系的了解。如果化石发现的质量和密度的预期能够得到证实，则应在随后的项目中对化石进行挖掘和分析，并最终将巴拉班赛组的恐龙动物群与西亚和东亚各自的动物群进行定性和统计比较。因此，可以测试吉尔吉斯动物群是更类似于其中一个还是另一个动物群，或者它是否代表了一种混合。有了这些数据，最终有可能确定触发东亚恐龙特有的潜在地理屏障的位置和时间框架，或者如果整个假设实际上只是基于不完整的化石记录。除了科学目标，潜在的后续项目还打算支持合作伙伴--以Aizek Bakirov博士为代表的比什凯克地质研究所，使他们能够逐步建立吉尔吉斯斯坦的现代科学收藏和独立的古生物学研究能力。

Dinosaurs are among the most successful and widely distributed land vertebrates of all time. Their fossil remains are also commonly found making them ideal candidates exploring the evolution and distribution patterns of vertebrates. In the Middle Jurassic, between 174 and 163 million years ago, many of the main groups of dinosaurs evolved or were on the way to become established. Unfortunately, dinosaur fossils from the Middle Jurassic are rare worldwide, so that the knowledge about their evolution is highly incomplete. In addition, the dinosaur fauna from east Asia possibly starts to evolve independently from the rest of the world in the Middle Jurassic, which culminated in the postulated isolation and endemism of that dinosaur fauna.The Balabansai Formation in the central Asian country of Kyrgyzstan might be a key to solve questions about the evolution and distribution patterns of Middle Jurassic dinosaurs: 1) This formation is dated as being of Middle Jurassic in age, 2) it is well-known as comprising dinosaur fossil-bearing sediments, and 3) it is located geographically, then, as now, right between western Eurasia and east Asia. The recent discoveries of two partial skeletons of a sauropod and a theropod dinosaur furthermore confirms that scientifically important finds can be expected in these sediments.The first objective of this preliminary project is the documentation of already discovered dinosaur fossils and to identify new localities in the field for a larger-scaled subsequent project. Due to the scarcity of adequate fossils from the Middle Jurassic worldwide, every single new find will significantly increase the knowledge on the evolution and relationships of dinosaurs. In case the expectations on the quality and density of fossil finds can be confirmed, the fossils shall, in the subsequent project, be excavated and analyzed, and the dinosaur fauna of the Balabansai Formation shall finally be compared qualitatively and by means of statistical methods with the respective faunas of western Eurasia and east Asia. Thus, it can be tested whether the Kyrgyz fauna is more similar to one or the other fauna or whether it represents a mixture. With these data at hand, it might finally be possible to determine the location and time frame of a potential geographical barrier triggering the endemism of east Asian dinosaurs or if this whole hypothesis is actually only based on the incomplete fossil record.Beyond the scientific goals, it is additionally intended in the potential subsequent project to support the cooperating Kyrgyz partner, the Institute of Geology in Bishkek represented by Dr. Aizek Bakirov, enabling them to stepwise establish a modern scientific collection and independent paleontological research capabilities in Kyrgyzstan.