Hansford James P, Turvey Samuel T
Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.
Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
R Soc Open Sci. 2018 Sep 26;5(9):181295. doi: 10.1098/rsos.181295. eCollection 2018 Sep.
Madagascar's now-extinct radiation of large-bodied ratites, the elephant birds (Aepyornithidae), has been subject to little modern research compared to the island's mammalian megafauna and other Late Quaternary giant birds. The family's convoluted and conflicting taxonomic history has hindered accurate interpretation of morphological diversity and has restricted modern research into their evolutionary history, biogeography and ecology. We present a new quantitative analysis of patterns of morphological diversity of aepyornithid skeletal elements, including material from all major global collections of aepyornithid skeletal remains, and constituting the first taxonomic reassessment of the family for over 50 years. Linear morphometric data collected from appendicular limb elements, and including nearly all type specimens, were examined using multivariate cluster analysis and the Bayesian information criterion, and with estimation of missing data using multiple imputation and expectation maximization algorithms. These analyses recover three distinct skeletal morphotypes within the Aepyornithidae. Two of these morphotypes are associated with the type specimens of the existing genera and , and represent small-bodied and medium-bodied aepyornithids, respectively. contains two distinct morphometric subgroups, which are identified as the largely allopatric species and The third morphotype, which has not previously been recognized as a distinct genus, is described as the novel taxon . represents the largest-bodied aepyornithid and is the world's largest bird, with a mean body mass of almost 650 kg. This new taxonomic framework for the Aepyornithidae provides an important new baseline for future studies of avian evolution and the Quaternary ecology of Madagascar.
马达加斯加现已灭绝的大型平胸鸟类——象鸟科（Aepyornithidae），与该岛的哺乳动物巨型动物群以及其他晚更新世巨型鸟类相比，受到的现代研究较少。该科复杂且相互矛盾的分类历史阻碍了对其形态多样性的准确解读，并限制了对其进化历史、生物地理学和生态学的现代研究。我们对象鸟骨骼元素的形态多样性模式进行了一项新的定量分析，其中包括来自全球所有主要象鸟骨骼遗骸收藏的材料，这是该科50多年来的首次分类重新评估。从附肢骨骼元素收集的线性形态测量数据，包括几乎所有的模式标本，使用多元聚类分析和贝叶斯信息准则进行了检验，并使用多重插补和期望最大化算法估计缺失数据。这些分析在象鸟科中发现了三种不同的骨骼形态类型。其中两种形态类型与现有属的模式标本相关，分别代表小型和中型象鸟。包含两个不同的形态测量亚组，被确定为主要异域分布的物种和。第三种形态类型，以前未被确认为一个独特的属，被描述为新分类单元。代表体型最大的象鸟，是世界上最大的鸟类，平均体重近650千克。这个象鸟科的新分类框架为未来鸟类进化和马达加斯加第四纪生态学研究提供了一个重要的新基线。
