Teeth from the Family Bovidae that are associated with our early humans ancestors are important for reconstructing paleoenvironments. However, age, degree of attrition, and taphonomic factors often make fossil identification difficult. A recent technique for classifying these teeth uses the size-and-shape of the occlusal surface as a summary of the surface, deriving features from this, and then using these features in machine learning classification algorithms. Bovid teeth have previously been classified using this method with features derived from coefficients of elliptical Fourier analysis (EFA). This study assesses the utility of using other shape representations for feature generation, specifically elastics shape analysis. Features were derived using this frame work for both shape only and size-and-shape (i.e. size is not considered a nuisance parameter), and those features were used as input for machine learning algorithms. We demonstrate that features derived elastic shape analysis generally outperform features derived from EFA in terms of cross validation classification accuracy. Finally, an application of the classification methods studied here was applied to fossils recovered from the deroofed Gladysvale External deposit (GVED), Gauteng Province, South Africa. Previous analyses of GVED identified a group of bovids as medium sized alcelaphines (Lacruz et al., 2002). Specifically, this study reclassified 32 unbroken, medium sized alcelaphines looking at shape and size-and-shape. The reclassifications increased the number of individuals and diversity of bovids recovered from the site. The results were used to generate a more precise paleoenvironmental reconstruction.

中文翻译：

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使用弹性形状分析对南非格拉迪斯维尔的牛科化石进行分类

与我们早期人类祖先相关的牛科牙齿对于重建古环境非常重要。然而，年龄、磨损程度和埋藏学因素常常使化石鉴定变得困难。最近对这些牙齿进行分类的技术使用咬合面的大小和形状作为表面的摘要，从中导出特征，然后在机器学习分类算法中使用这些特征。牛科动物的牙齿之前已使用这种方法进行分类，其特征源自椭圆傅里叶分析（EFA）的系数。本研究评估了使用其他形状表示进行特征生成的实用性，特别是弹性形状分析。使用该框架导出仅形状和大小和形状的特征（即大小不被视为有害参数），并且这些特征被用作机器学习算法的输入。我们证明，在交叉验证分类准确性方面，弹性形状分析派生的特征通常优于 EFA 派生的特征。最后，本文研究的分类方法被应用于从南非豪登省格拉迪斯维尔外部矿床（GVED）中回收的化石。先前对 GVED 的分析确定了一组牛科动物为中等体型的牛科动物（Lacruz 等，2002）。具体来说，这项研究根据形状以及大小和形状对 32 个完整的中型阿尔塞拉芬进行了重新分类。重新分类增加了从该地点恢复的牛科动物的个体数量和多样性。结果用于生成更精确的古环境重建。