Sthenurine kangaroos, extinct “giant kangaroos” known predominantly from the Plio-Pleistocene, have been proposed to have used bipedal striding as a mode of locomotion, based on the morphology of their hind limbs. However, sthenurine forelimb morphology has not been considered in this context, and has important bearing as to whether these kangaroos employed quadrupedal or pentapedal locomotion as a slow gait, as in extant kangaroos. Study of the correlation of morphology of the proximal humerus in a broad range of therian mammals shows that humeral morphology is indicative of the degree of weight-bearing on the forelimbs during locomotion, with terrestrial species being distinctly different from arboreal ones. Extant kangaroos have a proximal humeral morphology similar to extant scansorial (semi-arboreal) mammals, but sthenurine humeri resemble those of suspensory arboreal taxa, which rarely bear weight on their forelimbs, supporting the hypothesis that they used bipedal striding rather than quadrupedal locomotion at slow gaits. The humeral morphology of the enigmatic extinct “giant wallaby,” Protemnodon , may be indicative of a greater extent of quadrupedal locomotion than in extant kangaroos.

中文翻译：

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肱骨近端形态表明已灭绝的巨型袋鼠的不同运动模式

Sthenurine 袋鼠，主要从上新世已知的已灭绝的“巨型袋鼠”，已被提议使用双足跨步作为一种运动方式，基于其后肢的形态。然而，在这种情况下没有考虑 sthenurine 前肢形态，并且对于这些袋鼠是否采用四足或五足运动作为慢步态具有重要意义，就像现存的袋鼠一样。对广泛的therian哺乳动物肱骨近端形态相关性的研究表明，肱骨形态是运动过程中前肢承重程度的指标，陆生物种与树栖物种明显不同。现存袋鼠的肱骨近端形态类似于现存的扫描（半树栖）哺乳动物，但 sthenurine humeri 类似于悬吊树栖类群，它们很少用前肢承受重量，支持了他们在慢步态下使用​​双足跨步而不是四足移动的假设。神秘的灭绝“巨型袋鼠”Protemnodon 的肱骨形态可能表明四足运动的程度比现存袋鼠更大。