Dinosaur Evolution and Habitat Bottlenecks

蒙大拿州的圣玛丽河和柳溪组为研究来自上海岸平原环境的晚白垩世恐龙动物群提供了无与伦比的机会，特别是为分析栖息地瓶颈及其对大型陆地生物灭绝和辐射的影响提供了无与伦比的机会。1986年约翰霍普金斯大学医学院的研究表明，进一步的探索将产生重要的补充据我们对美国西部内陆晚白垩世生物群的了解，建议(1)用两个野外季节收集，圣玛丽河和柳树溪地层的测绘和详细的地层工作(包括1986年才进行侦察的地区)；(2)分析从圣玛丽河地层收集的三种或三种以上不同类型的蛋；(3)描述幼年和胚胎恐龙的遗骸(包括手头材料和预期发现的恐龙)；(4)描述成年恐龙和其他相关爬行动物；以及(5)从前面提到的关于圣玛丽河和柳溪恐龙进化的数据中得出什么结论，特别是它们与通过熊掌海退化而开放陆地栖息地的关系。

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.