Myth of the
            <i>QANTAS</i>
            leap: perspectives on the evolution of kangaroo locomotion

Janis, Christine M.; O'Driscoll, None Adrian M.; Kear, Benjamin P.

doi:10.1080/03115518.2023.2195895

Cited by 8 publications

(26 citation statements)

References 88 publications

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“…and Protemnodon viator) experienced high stresses across all hopping and striding simulations, with the implication that they either did not hop, or were not regular hoppers like extant large kangaroos. P. viator showed low stresses during the bounding simulation, supporting previous hypothesises of a more quadrupedal gait in large species of Protemnodon (seeJanis et al, 2023; Jones & Janis, under revision;Wagstaffe et al, 2022).The locomotion of the giant specimen of Macropus remains a mystery.Sthenurine kangaroos exhibit less overall astragalar stress than macropodines in these simulations, even in a simulated hopping gait, and show lower stress in the striding simulations (notably in the faster striding simulated for P. browneorum). The enlarged and strengthened medial trochlear ridge of the sthenurine astragalus appears to grant lower overall stress in this area under any simulated gait (although this is still the area of highest stress).…”

supporting

confidence: 83%

“…But MWAM in the hopping simulation is still lower than that of M. giganteus. As previously noted, P. browneorum was certainly not too big to hop, although its postcranial anatomy is not indicative of the specialized hopping of large extant kangaroos (Janis et al, 2014(Janis et al, , 2023, and it may have been performing both hopping and bipedal striding, perhaps at different speeds. Given the poorer F I G U R E 6 von Mises stress patterns for Notamacropus eugenii and Dendrolagus inustus.…”

Section: Macropus Giganteus and Procoptodon Browneorummentioning

confidence: 82%

“…The extinct (Pleistocene) medium-to-large macropodine Protemnodon viator (formerly P. brehus, see Kerr et al, 2024: this individual ~97 kg) is compared here with the similarly sized Late Miocene basal sthenurine, Hadronomas puckridgi (this individual ~73 kg). Protemnodon viator has long been considered to have similar locomotion to extant kangaroos, but its postcranial morphology is more indicative of quadrupedal bounding, although it was probably able to hop to some extent (Janis et al, 2023;Jones & Janis, under revision). Hadronomas puckridgi differs from the other sthenurines considered here in retaining the fifth pedal digit.…”

Section: Methodsmentioning

confidence: 99%

“…browneorum (Janis et al, 2023) indicates that it would have been poor at withstanding torque at the ankle with a crouched posture.…”

Section: Macropus Giganteus and Procoptodon Browneorummentioning

confidence: 99%

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Finite element analysis of kangaroo astragali: A new angle on the ankle

Murphy,

Rowe,

Rayfield

et al. 2024

Journal of Morphology

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Using finite element analysis on the astragali of five macropodine kangaroos (extant and extinct hoppers) and three sthenurine kangaroos (extinct proposed bipedal striders) we investigate how the stresses experienced by the ankle in similarly sized kangaroos of different hypothesized/known locomotor strategy compare under different simulation scenarios, intended to represent the moment of midstance at different gaits. These tests showed a clear difference between the performance of sthenurines and macropodines with the former group experiencing lower stress in simulated bipedal strides in all species compared with hopping simulations, supporting the hypothesis that sthenurines may have utilized this gait. The Pleistocene macropodine Protemnodon also performed differently from all other species studied, showing high stresses in all simulations except for bounding. This may support the hypothesis of Protemnodon being a quadrupedal bounder.

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supporting

confidence: 83%

Section: Macropus Giganteus and Procoptodon Browneorummentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

“…browneorum (Janis et al, 2023) indicates that it would have been poor at withstanding torque at the ankle with a crouched posture.…”

Section: Macropus Giganteus and Procoptodon Browneorummentioning

confidence: 99%

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Finite element analysis of kangaroo astragali: A new angle on the ankle

Murphy,

Rowe,

Rayfield

et al. 2024

Journal of Morphology

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“…This suggests that previous projections of tendon stress may have overestimated the body mass at which tendons reach their safety limit ('safety factor' of 1). Snelling et al (2017) estimated the maximum body mass to remain above this limit was approximately 160 kg, but even if we consider this is a conservative prediction, it is far lower than the projected mass of extinct macropodids (up to 240 kg (Helgen et al 2006, Janis et al 2023). Thus we expect there must be a body mass where postural changes shift from contributing to stress to mitigating it (Dick and Clemente 2017).…”

Section: Were Macropods Performance or Size Limited?mentioning

confidence: 73%

Unlocking the secrets of kangaroo locomotor energetics: Postural adaptations underpin increased tendon stress in hopping kangaroos

Thornton,

Dick,

Hutchinson

et al. 2024

Preprint

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Hopping kangaroos exhibit remarkably little change in their rate of metabolic energy expenditure with locomotor speed compared to other running animals. This phenomenon may be related to greater elastic energy savings due to increasing tendon stress; however, the mechanisms which enable the rise in stress remain poorly understood. In this study, we created a three-dimensional (3D) kangaroo musculoskeletal model, integrating 3D motion capture and force plate data, to analyse the kinematics and kinetics of hopping red and grey kangaroos. Using our model, we evaluated how body mass and speed influence (i) hindlimb posture, (ii) effective mechanical advantage (EMA), and (iii) the associated tendon stress in the ankle extensors and (iv) ankle work during hopping. We found that increasing ankle dorsiflexion and metatarsophalangeal plantarflexion likely played an important role in decreasing ankle EMA by altering both the muscle and external moment arms, which subsequently increased energy absorption and peak tendon stress at the ankle. Surprisingly, kangaroo hindlimb posture appeared to contribute to increased tendon stress, thereby elucidating a potential mechanism behind the increase in stress with speed. These posture-mediated increases in elastic energy savings could be a key factor enabling kangaroos to achieve energetic benefits at faster hopping speeds, but may limit the performance of large kangaroos due to the risk of tendon rupture.

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Proportional variation and scaling in the hindlimbs of hopping mammals, including convergent evolution in argyrolagids and jerboas

Jones,

Travouillon,

Janis

2024

J Mammal Evol

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Bipedal hopping is a mode of locomotion seen today in four rodent lineages and one clade of marsupials. The Argyrolagidae, marsupials from the Oligocene to Pliocene of South America, have also been considered to be hoppers. These lineages all convergently evolved similar general morphologies, with elongated hindlimbs, reduced forelimbs, and elongated tails, and their similarities and variations may be informative in understanding the evolution of hopping in mammals. This study uses principal components analysis and log-log regressions to investigate variation in the hindlimb proportions of these hopping mammals and how this relates to body mass. We find that the distribution of hopping mammal masses is bimodal, divided at roughly 500 g. These two domains among hopping mammals may reflect optimisation for different forms of hopping locomotion; species under 500 g tend to have more elongated metatarsals relative to the rest of their hindlimbs, perhaps to facilitate rapid vertical jumps for predator evasion, a behaviour not seen in larger hoppers. Despite this bimodal distribution in body mass, hindlimb proportions cluster more by clade than mass, with some similarities among clades being especially noteworthy. The jerboas (Dipodidae, Rodentia) and Argyrolagidae share a particularly extreme degree of metatarsal elongation. The drivers of this convergence are unclear, but we hypothesise that the elongation may be related to the reduction/fusion of metatarsals in these groups, or a greater reliance on bipedality at slow speeds, as jerboas are known to utilise multiple bipedal gaits in addition to hopping.

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Myth of the QANTAS leap: perspectives on the evolution of kangaroo locomotion

Cited by 8 publications

References 88 publications

Finite element analysis of kangaroo astragali: A new angle on the ankle

Finite element analysis of kangaroo astragali: A new angle on the ankle

Unlocking the secrets of kangaroo locomotor energetics: Postural adaptations underpin increased tendon stress in hopping kangaroos

Proportional variation and scaling in the hindlimbs of hopping mammals, including convergent evolution in argyrolagids and jerboas

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