Dinosaur Evolution and Habitat Bottlenecks

蒙大拿州的圣玛丽河和杨柳溪地层 为晚白垩世的研究提供了前所未有的机遇 来自沿海平原环境的恐龙动物群， 特别是分析生境瓶颈及其 大型陆栖生物消光和辐射效应 约翰霍普金斯大学医学院在1986年 它确信，进一步的探索将产生重要的补充， 我们对西部晚白垩世生物群的了解 建议（1）将两个领域 收集、绘图和详细地层工作的季节 圣玛丽河和杨柳溪地层（包括 1986年才勘探）;（2）分析三个或更多 从圣玛丽河采集的不同种类的卵 形成;（3）描述幼年和胚胎恐龙 （4）现有材料和预期发现物; 描述成年恐龙和其他相关的爬行动物;以及 (5)从先前的研究中得出合理的结论， 提到了关于圣玛丽河演变的数据， 杨柳溪恐龙，特别提到他们的 与开放陆地生境的关系 熊爪海的回归

The St. Mary River and Willow Creek Formations of Montana offer unequalled opportunities for the study of Late Cretaceous dinosaur faunas from upper coastal plains environments and particularly for the analysis of habitat bottlenecks and their effect on extinction and radiation of large bodied terrestrial from the Johns Hopkins University School of Medicine in 1986 make it certain that further exploration will yield important additions to our knowledge of the Late Cretaceous biota of the western interior of the U.S. It is proposed (1) to devote two field seasons to collecting, mapping, and detailed stratigraphic work in the St. Mary River and Willow Creek Formations (including areas only reconnoitered in 1986); (2) to analyze the three or more distinct types of eggs collected from the St. Mary River Formation; (3) to describe the juvenile and embryonic dinosaur remains (both material in hand and expected finds); (4) to describe the adult dinosaurs and other associated reptiles; and (5) to draw what conclusions are justified from the previously mentioned data about the evolution of the St. Mary River and Willow Creek dinosaurs, with special reference to their relationship to the opening of terrestrial habitats through the regression of the Bearpaw Sea.