Humeri have been useful bones in taxonomic determinations of extinct penguins. In the context of neontological taxonomic studies, however, their potential remains unsatisfactorily explored. Here, the variation of the overall closed-outline shape of 60 humeri, assignable to five genera of extant penguins, was investigated. A set of normalized outlines was quantified via elliptical Fourier analysis and subjected to linear discriminant analysis on principal component scores extracted from harmonic coefficients. These geometric representations proved to be a source of easily extractable genus-level taxonomic information. The constructed model provided meaningful discrimination between taxa: the first two linear discriminants captured almost 90% of between-group variance. A cross-validation method based on jackknifing yielded 93% correct identifications, and statistically significant differences between group centroids were also detected (multivariate analysis of variance, p < 0.05). Predictions of genus membership for the intentionally noisy test data (20 outlines) were accurate in 80% of cases.

中文翻译：

---

企鹅肱骨的轮廓形状分析：一种稳健的分类方法

Humeri 一直是已灭绝企鹅分类学确定的有用骨骼。然而，在新生儿分类学研究的背景下，它们的潜力仍未得到令人满意的探索。在这里，研究了 60 个肱骨的整体闭合轮廓形状的变化，可分配给现存的五个企鹅属。通过椭圆傅里叶分析量化一组归一化轮廓，并对从谐波系数中提取的主成分分数进行线性判别分析。这些几何表示被证明是易于提取的属级分类信息的来源。构建的模型提供了分类群之间有意义的区分：前两个线性区分项捕获了近 90% 的组间方差。基于 jackknifing 的交叉验证方法产生了 93% 的正确识别，并且还检测到组质心之间的统计显着差异（多变量方差分析，p < 0.05）。在 80% 的情况下，对故意嘈杂的测试数据（20 个大纲）的属成员关系的预测是准确的。