ABSTRACT Dufrenoyia is a relevant ammonite genus for discussing the lower–upper Aptian boundary on a supraregional scale. We present the first comprehensive account on the genus from Germany, recording the two index species Dufrenoyia furcata and D. transitoria from the Ahaus area. This is based on a yet undescribed historical collection by the German nineteenth century palaeontologist Clemens Schluter. Our stratigraphic conclusions indicate that Dufrenoyia furcata Zone deposits are present in the poorly-known highest lower Aptian succession in Germany, indicating similarities to the well-known successions in England and France. An alleged dimorphism in Dufrenoyia furcata is discussed.

中文翻译：

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来自德国的 A (Ammonoidea, Deshayesitidae) 动物群：Aptian 上下边界带沉积的证据

摘要 Dufrenoyia 是一个相关的菊石属，用于在超区域尺度上讨论上下阿普蒂安边界。我们首次全面介绍了来自德国的该属，记录了来自阿豪斯地区的两个指标种 Dufrenoyia furcata 和 D. transtoria。这是基于德国 19 世纪古生物学家 Clemens Schluter 尚未描述的历史收藏。我们的地层结论表明 Dufrenoyia furcata 带矿床存在于德国鲜为人知的最高下 Aptian 层序中，表明与英国和法国众所周知的层序相似。讨论了 Dufrenoyia furcata 中所谓的二态性。