The taxonomy of the calcareous nannofossil Arkhangelskiella is revised using the results of a biometric analysis performed on 599 specimens from various stratigraphic levels throughout the upper Campanian-Maastrichtian of the Stevns-1 borehole, Denmark. Combined qualitative labelling and biometric measurements suggest that this genus comprises at least three distinct morphogroups in this stratigraphic interval, with possibly one additional morphotype. The results show that the descriptions formerly used for the erection of these groups as distinct species do not fit to their observed range in the coccolith length and in the rim width, and that the central opening is an important additional parameter allowing distinction between the different morphogroups. Biometric analysis shows, however, that the morphogroups are strongly overlapping on all measured parameters. Therefore, the three distinct variants of Arkhangelskiella cymbiformis (var. NT, var. N and var. W) formerly described by Varol are reintroduced and emended rather than using distinct species. In addition, a fourth variant is described, A. cymbiformis var. SW. Using observed relationships between the parameters as well as stratigraphic ranges of these groups throughout the latest Cretaceous, evolutionary trends are outlined.

中文翻译：

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丹麦 Stevns-1 钻孔上坎帕阶-马斯特里赫特阶中 Arkhangelskiella 群的生物特征分析：分类学意义和进化趋势

钙质纳米化石 Arkhangelskiella 的分类学使用对丹麦 Stevns-1 钻孔的上坎帕阶-马斯特里赫特阶不同地层水平的 599 个标本进行的生物特征分析的结果进行了修订。结合定性标记和生物特征测量表明，该属在这个地层间隔中至少包含三个不同的形态群，可能还有一个额外的形态类型。结果表明，以前用于将这些组作为不同物种竖立起来的描述不符合它们在球石长度和边缘宽度方面的观察范围，并且中央开口是一个重要的附加参数，可以区分不同的形态组. 然而，生物特征分析表明，形态群在所有测量参数上强烈重叠。因此，以前由 Varol 描述的三种不同的 Arkhangelskiella cymbiformis（变种 NT、变种 N 和变种 W）被重新引入和修正，而不是使用不同的物种。此外，还描述了第四个变种，A. cymbiformis var. 西南。使用这些群体在整个最新白垩纪期间观察到的参数和地层范围之间的关系，概述了进化趋势。