Premise of research. Fossil fruit and seed floras are valuable because of the wealth of taxonomic characters that they can provide, but they are rare in the Cenozoic of North America. Here, we document a fossil fruit and seed flora from the Paleocene Denver Formation of the Denver Basin, Littleton, Colorado, representing the first account of an early Paleocene carpoflora in North America. This locality has previously yielded a rich and well-studied therian and sauropsid fauna confirming a Puercan age. In conjunction with these vertebrate records, the Littleton flora serves as an ecological snapshot of a transitional time in both angiosperm and vertebrate lineages following the K-T mass extinction event. Methodology. Disseminules were studied with reflected light and X-ray micro–computed tomography. Pivotal results. The flora contains at least 15 different morphotypes, including four members of the Cornales (Amersinia littletonensis sp. n., Langtonia parva sp. n., Mastixicarpum hoodii sp. n., and Portnallia alexanderi sp. n.). The occurrence of Kingsboroughia rostellata (Lesquereux) comb. n., a close relative of Meliosma (Sabiaceae), is among the earliest records for this genus in North America. Although the morphology of the Littleton fruits and seeds is consistent with animal dispersal and in agreement with dietary preferences suggested by mammalian dentition, wear from predation is not evident in any of these specimens. Conclusions. The fruits and seeds reveal components of the early Paleocene Denver Basin flora that were not known from prior investigations of leaf assemblages. However, modern-day relatives of the Littleton taxa may occupy environments similar to those inferred for other Paleocene floras in the Denver Basin. Although the Littleton disseminules were found to have larger fruits and a wider range of sizes than other Paleocene floras, they fit into previously recognized trends of increasing seed size from the late Cretaceous through the early Tertiary.

中文翻译：

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来自美国科罗拉多州丹佛盆地的早古新世 Carpoflora 及其对动植物相互作用和果实大小进化的影响

研究的前提。化石果实和种子植物群很有价值，因为它们可以提供丰富的分类特征，但它们在北美新生代中很少见。在这里，我们记录了来自科罗拉多州利特尔顿丹佛盆地古新世丹佛组的化石水果和种子植物群，代表了北美早期古新世果树植物群的第一个记载。该地区以前曾产生丰富且经过充分研究的兽类和蜥脚类动物群，证实了普尔坎时代。结合这些脊椎动物记录，Littleton 植物群作为 KT 大灭绝事件后被子植物和脊椎动物谱系过渡时期的生态快照。方法。使用反射光和 X 射线显微计算机断层扫描研究散布。关键结果。植物群包含至少 15 种不同的形态类型，包括 Cornales 的四个成员（Amersinia littletonensis sp. n.、Langtonia parva sp. n.、Mastixicarpum hoodii sp. n. 和 Portnallia alexanderi sp. n.）。Kingsboroughia rostellata (Lesquereux) 梳子的发生。n. 是 Meliosma (Sabiaceae) 的近亲，是北美对该属最早的记录之一。尽管利特尔顿果实和种子的形态与动物分布一致，并且与哺乳动物牙列建议的饮食偏好一致，但在这些标本中，捕食造成的磨损并不明显。结论。果实和种子揭示了早期古新世丹佛盆地植物群的成分，这些成分在之前对叶组合的调查中是未知的。然而，利特尔顿分类群的现代近亲可能居住在与推测的丹佛盆地其他古新世植物群相似的环境中。尽管发现 Littleton 散播植物比其他古新世植物群具有更大的果实和更广泛的大小范围，但它们符合先前公认的从白垩纪晚期到第三纪早期种子大小增加的趋势。