Ontogenetic Scaling of the Humerus in Sea Turtles and Its Implications for Locomotion

Nishizawa, Hideaki; Asahara, Masakazu; Kamezaki, Naoki

doi:10.2108/zsj.30.211

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…Carrier & Leon () hypothesized that ectothermic animals show isometric or positive allometric growth of limb bone thickness vs. body mass due to their slower bone structural changes during growth. Later studies found the midshaft diameter, circumference and cross‐sectional mechanical properties of limb bone scale isometrically or positively against body mass/limb bone length in extant crocodylians and lizards, but isometrically or negatively in turtles (Meers, ; Kilbourne & Makovicky, ; Nishizawa, Asahara & Kamezaki, ). Our results showed that femur circumference of C. yacare grows with marginally negative allometry against the presacral length (body size proxy) and differs from the positive allometry of A. mississippiensis (Fig.…”

Section: Discussionmentioning

confidence: 99%

Allometric growth of limb and body proportions in crocodylians

Iijima

Kubo

2019

Journal of Zoology

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Crocodylia is the sole extant remnant of quadrupedal archosaurs playing a pivotal role in understanding the evolution of growth allometry in the archosaur locomotor apparatus. However, among crocodylians, the postnatal growth of the postcranial skeleton has almost exclusively been examined in Alligator mississippiensis, and whether other species share the same growth pattern is unknown. Here, we tested whether the following allometric trends are conserved across Crocodylia: (1) forelimb length grows isometrically relative to hindlimb length; (2) fore‐ and hindlimb lengths become relatively shorter with increasing body size; and (3) long bone cross‐sectional geometry becomes more robust relative to body size. We examined the relationships of limb lengths, stylopodial circumferences and presacral length (body size proxy) in extant crocodylians using reduced major axis regressions and compared the slopes among species. The result revealed non‐uniform growth patterns of limb architecture among living crocodylians. Generally, the hindlimb grows with negative allometry against the forelimb in non‐gavialid crocodylians, whereas two gavialids (Gavialis gangeticus and Tomistoma schlegelii) showed isometry in hind‐ vs. forelimb length scaling, potentially reflecting their unique locomotor ecology. Femur circumference scales negatively against humerus circumference in most of the species examined, which may be related to the anterior shift of the center of mass during growth. Stylopodial circumferences scale variously against stylopodial lengths and presacral length in crocodylians, lending little support to hypotheses that these allometries correlate with adult body size or metabolism (i.e. ectothermic or endothermic) in tetrapods.

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Section: Discussionmentioning

confidence: 99%

Allometric growth of limb and body proportions in crocodylians

Iijima

Kubo

2019

Journal of Zoology

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Design and Control of Turtle Locomotion-Inspired Robots Actuated By Antagonistic Shape Memory Alloy Springs

Huang

2022

IEEE/ASME Trans. Mechatron.

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Wading through water: effects of water depth and speed on the drag and kinematics of walking Chilean flamingos, Phoenicopterus chilensis

Palecek

Novak

Blob

2021

Journal of Experimental Biology

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Wading behaviours, in which an animal walks while partially submerged in water, are present in a variety of taxa including amphibians, reptiles, mammals, and birds. Despite the ubiquity of wading behaviours, few data are available to evaluate how animals adjust their locomotion to accommodate changes in water depth. Because drag from water might impose additional locomotor costs, wading animals might be expected to raise their feet above the water up to a certain point until such behaviours lead to awkward steps and are abandoned. To test for such mechanisms, we measured drag on models of the limbs of Chilean flamingos (Phoenicopterus chilensis) and measured their limb and body kinematics as they walked and waded through increasing depths of water in a zoo enclosure. Substantial drag was incurred by models of both open- and closed-toed feet, suggesting that flamingos could avoid some locomotor costs by stepping over water, rather than through it, during wading. Step height was highest while wading through intermediate water depths and while wading at a faster speed. Stride length increased with increasing water depth and velocity, and the limb joints generally flexed more while moving through intermediate water depths. However, movements of the head and neck were not strongly correlated with water depth or velocity. Our results show a wide range of kinematic changes that occur to allow wading birds to walk through different water depths, and have implications for better understanding the locomotor strategies employed by semi-aquatic species.

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Ontogenetic Scaling of the Humerus in Sea Turtles and Its Implications for Locomotion

Cited by 3 publications

References 33 publications

Allometric growth of limb and body proportions in crocodylians

Allometric growth of limb and body proportions in crocodylians

Design and Control of Turtle Locomotion-Inspired Robots Actuated By Antagonistic Shape Memory Alloy Springs

Wading through water: effects of water depth and speed on the drag and kinematics of walking Chilean flamingos, Phoenicopterus chilensis

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