Late Cretaceous dinosaurs in eastern USA—A taphonomic and biogeographic model of occurrences.
Late Cretaceous dinosaurs in eastern USA—A taphonomic and biogeographic model of occurrences.
复制标题
美国东部白垩纪晚期的恐龙——事件的埋藏学和生物地理学模型。
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
D. Schwimmer
中科院分区：
文献类型：
--
作者：
D. Schwimmer
美国东部沿海平原包含一个晚白垩世恐龙组合，其类群多样性有限，但分布广泛，数量相当丰富。标本的年代从Santonian到Maastrichtian晚期。所有晚白垩世东部恐龙标本都产于陆缘或海相地层，因此所有这些化石都可能是异地的。新的材料和见解对这些海洋事件的埋藏学产生了影响，这表明河流运输的漂浮尸体，许多被鲨鱼清除，构成了东部海洋恐龙记录的大部分。几乎没有证据表明整个东部露头的动物区系是地方性的：各地的化石收集都以鸭嘴龙和未成熟的兽脚亚目为主，主要是鸭嘴龙科（参见图1）。阿尔伯特龙（英语：Dryptosaurus aquilunguis）所有其他分类群的遗骸都很罕见，有几个是从单一事件中发现的。东部鸭嘴龙类和鸭嘴龙科与西部的类群相似，这意味着它们的祖先在内陆海道的极端退化期间迁移。这种迁移的时间受到Santonian时间在美国东部存在的典型西方分支的限制，以及东部完全没有角龙。迁移必须开始或发生在Santonian期间，并且必须在中坎帕尼亚之后不可能。
The eastern Coastal Plains of the USA contain a Late Cretaceous dinosaur assemblage of limited taxic diversity, but with wide distribution and reasonably good abundance. The ages of specimens range from Santonian through late Maastrichtian. All Late Cretaceous eastern dinosaur specimens occur in pericontinental or marine strata, and therefore all such fossils are likely to be allochthonous. New materials and insights bear on the taphonomy of these marine occurrences, suggesting that fluvially-transported, floating carcasses, many scavenged by sharks, make up most of the eastern marine dinosaur record. There is little evidence of faunal provinciality across the entire eastern outcrop: fossil collections everywhere are dominated by hadrosaurines and immature theropods, mostly tyrannosaurids (cf. Albertosaurus) and Dryptosaurus aquilunguis. Remains of all other taxa are rare and several are known from single occurrences. Eastern hadrosaurines and tyrannosaurids appear generically similar to western taxa, implying migration by their ancestors during extreme regressions of the Interior seaway. The timing of such migrations is constrained by the presence of characteristically western clades in eastern USA by Santonian time, and by the complete absence of ceratopsians in the East. Migration must have begun or occurred during the Santonian, and must not have been possible after the middle Campanian.