Macrauchenia patachonica Owen, 1838 was among the last and largest litopterns, an extinct order of South American native ungulates. Macrauchenia patachonica had anatomical peculiarities as extremely retracted nasals, enlarged cervical vertebrae, and limb bones proportions without good living analogs that lead to asking about its paleobiology. To quantitatively assess the strange combination of limb bone features in M. patachonica, we constructed an indicator of differences in anatomical adaptations for efficient running between forelimb and hind limb (IDFH). We also made a multivariate analysis using data on osteological ratios of living mammals and two other litopterns. We discuss several biomechanical and paleobiological implications of the striking differences between hind limb and forelimb design in M. patachonica. Our main suggestion is that M. patachonica, during fast locomotion, probably used a posture with the neck in a horizontal position.

Macrauchenia patachonica Owen, 1838 是最后的也是最大的近足类动物之一，是南美本土有蹄类动物的一个灭绝目。Macrauchenia patachonica具有解剖学特征，如极度内缩的鼻腔、增大的颈椎和四肢骨骼比例，没有良好的活体类似物，这导致询问其古生物学。定量评估木耳四肢骨特征的奇怪组合，我们构建了一个指标，表明前肢和后肢 (IDFH) 之间有效运行的解剖适应性差异。我们还使用活体哺乳动物和其他两种短鳍动物的骨学比率数据进行了多变量分析。我们讨论了M. patachonica后肢和前肢设计之间显着差异的几个生物力学和古生物学意义。我们的主要建议是M. patachonica在快速运动时可能使用颈部处于水平位置的姿势。