Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC). Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Buenos Aires, Argentina.
Anat Rec (Hoboken). 2022 Nov;305(11):3243-3253. doi: 10.1002/ar.24891. Epub 2022 Feb 14.
Anseriformes is a diverse group of birds that comprises screamers, the Magpie Goose, and swans ducks and geese, with a relatively rich fossil record. Waterfowl live in close relation to water bodies, but show a diversity of locomotory habits, being typically categorized as walkers, dabblers, and divers. Owing to its functional significance and high preservation potential, the tarsometatarsus has been considered to be a "key" element upon which to base ecomorphological inferences in fossil waterfowl. For instance, based on features of the tarsometatarsus the Miocene flightless duck Cayaoa bruneti and the Oligocene-Miocene large waterfowl Paranyroca have been inferred as divers. Herein, we use a geometric morphometric approach and comparative methods to assess the phylogenetic and ecomorphological signals in the shape and size of waterfowl tarsometatarsi in relation to their locomotory habits. We also apply phylogenetic flexible discriminant analysis (pFDA) to test the inferred diving habits in the extinct waterfowl Cayaoa and Paranyroca. Extant waterfowl species are largely distributed according to their locomotory habit along the main axis of variation in the shape space, a pattern mirrored by the phylogenetic generalized least squares model, which shows that a third of the shape variation is significantly explained by the habit. The pFDA reclassifies correctly almost all extant species and classified with high posterior probabilities the fossil Cayaoa and Paranyroca as a diver and as a dabbler, respectively. Our quantitative multivariate approach confirms the tarsometatarsus as a useful source of data upon which reliably assesses locomotory habits of fossil waterfowl.
雁形目是一个多样化的鸟类群体，包括鸣禽、鹊鹅和天鹅、鸭和鹅，具有相对丰富的化石记录。水禽生活在水体附近，但表现出多种运动习性，通常被归类为步行者、涉禽和潜水者。由于其功能意义和高保存潜力，跗跖骨被认为是基于化石水禽进行生态形态学推论的“关键”元素。例如，基于跗跖骨的特征，中新世的不会飞的鸭子 Cayaoa bruneti 和渐新世-中新世的大型水禽 Paranyroca 被推断为潜水者。在此，我们使用几何形态测量方法和比较方法来评估水禽跗跖骨的形状和大小与运动习性之间的系统发育和生态形态学信号。我们还应用系统发育灵活判别分析（pFDA）来测试已灭绝的水禽 Cayaoa 和 Paranyroca 的推断潜水习性。现生水禽物种主要根据其运动习性分布在形状空间的主轴线附近，这一模式反映在系统发育广义最小二乘模型中，该模型表明，三分之一的形状变异可以通过习性得到很好的解释。pFDA 几乎正确地重新分类了所有现生水禽物种，并以高后验概率将化石 Cayaoa 和 Paranyroca 分别归类为潜水者和涉禽。我们的定量多变量方法证实跗跖骨是一种有用的数据源，可以可靠地评估化石水禽的运动习性。
