Terrestrial locomotion in monotremes (Mammalia: Monotremata)

Pridmore, Peter A.

doi:10.1111/j.1469-7998.1985.tb05613.x

Cited by 44 publications

(31 citation statements)

References 15 publications

(16 reference statements)

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“…We will discuss it in detail later. Here, it is worth noting that the gait description in this paper almost coincides with the previous description by Pridmore ().…”

Section: Introductionmentioning

confidence: 67%

“…Then, Pridmore () confirmed the conclusion of Jenkins Jr () as to the humeral and femoral motion by applying a similar cineradiographic method to another monotreme, the platypus Ornithorhynchus anatinus Shaw, 1799. Also, Pridmore () considered non‐X‐ray cinematographic records of walking platypus as well as of both tachyglossid genera. The walking speeds were not reported, and the gait was described but qualitatively.…”

Section: Introductionmentioning

confidence: 99%

“…All use diagonal or near‐diagonal patterns of limb support. However, the synchronization between diagonal limb pairs is inexact and any forelimb is always somewhat phase‐advanced with respect to the contralateral hindlimb’ (Pridmore, , p. 58). In other words, the walk was regarded as more or less trot‐like, although not the true trot.…”

Section: Introductionmentioning

confidence: 99%

“…One photo and one drawing of the platypus' track and two photos and one drawing of the short‐beaked echidna's track supplied with brief descriptions have been published by Triggs (). Contrary to Pridmore () and Fish et al . (), Triggs describes the monotreme walk as pacing.…”

Section: Introductionmentioning

confidence: 99%

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An evolutionary perspective on the walking gait of the long‐beaked echidna

Gambaryan

Kuznetsov

2013

Journal of Zoology

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The speed, gait and trackway of the long‐beaked echidna's walk are reported for the first time. The gait formula is devised. Despite its sprawling limb posture, echidna's walking technique shows fundamental differences from that of the classical sprawlers such as urodelans and lizards, which are: (1) the presence of the pace‐like lateral stages of support and even their prevalence over the diagonal ones; (2) the narrow, though sprawling, limb posture and, consequently, the narrow trackway; (3) rolling, skidding and yawing of the trunk from side to side; (4) forelimb in‐fingerness, which presumably provides the major thrust for these side‐to‐side movements. On the whole, the echidna's sprawling type is more upright than in urodelans and lizards and is closer to the parasagittal type of therians. Like therians, echidnas already employ dynamic equilibration instead of the static one. The question is posed of whether mammalian ancestors have ever walked in the manner of urodelans and lizards.

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“…We will discuss it in detail later. Here, it is worth noting that the gait description in this paper almost coincides with the previous description by Pridmore ().…”

Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An evolutionary perspective on the walking gait of the long‐beaked echidna

Gambaryan

Kuznetsov

2013

Journal of Zoology

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“…We have argued that through the cross-couplet linkage they provide a system of trunk support across diagonal feet during trotting locomotion (Reilly and White, 2003). Based on the appearance of epipubic bones in the fossil record, the lever system appeared in concert with the appearance of mammalian grade pelvis and the shift to an erect limb posture from the semi-upright posture of advanced cynodont ancestors (Jenkins, 1970;Pridmore, 1985). This also occurred in concert with the first evidence of a diaphragm (Jenkins, 1970;Crompton and Jenkins 1979) at a time when mammals are also thought to have shifted to expanded locomotor needs associated with higher metabolic rates (Crompton et al, 1978;Bennett and Ruben, 1979;Ruben et al, 1987).…”

Section: The Loss Of Epipubic Levers and The Basal Condition In Theriansmentioning

confidence: 99%

Abdominal muscle function in ventilation and locomotion in new world opossums and basal eutherians: Breathing and running with and without epipubic bones

Reilly

McElroy

White

2009

Journal of Morphology

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All tetrapods have the same four basic abdominal hypaxial muscle layers that wrap around the abdomen between the pelvis, ribcage, and spine. However, the marsupials and our immediate mammalian ancestors have epipubic bones extending anteriorly into the ventral hypaxial layers with two additional muscles connecting them to the ventral midline and femur. Studies of two marsupials have shown that all of the abdominal hypaxials play a part bilaterally in resting ventilation and during locomotion there is an asymmetrical pattern of activity as the hypaxial muscles form a cross-couplet linkage that uses the epipubic bone as a lever to provide long-axis support of the body between diagonal limb couplets during each step. The cross-couplet epipubic lever system defines the earliest mammals and is lost in placental mammals. To expand our understanding of the evolution of mammalian abdominal muscle function and loco-ventilatory integration we tested the generality of the cross-couplet system in marsupials and conducted the first formal studies of hypaxial abdominal motor patterns in generalized placental mammals focusing on a representative rodent and insectivore. These new data reveal 1) that continuous abdominal muscle tonus during resting ventilation and a 1:1 breath to step cycle during locomotion appear to be the basal condition for mammals, 2) that the loss of epipubic bones in eutherians is associated with a shift from the cross-couplet dominated motor pattern of marsupials to a shoulder-to-pelvis system with unilateral activation of abdominal muscles during locomotion and 3) that hypaxial function in generalized eutherians is more similar to marsupials than cursorial mammals.

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The Role of Cross‐Sectional Geometry, Curvature, and Limb Posture in Maintaining Equal Safety Factors: A Computed Tomography Study

Brassey

Kitchener

Withers

et al. 2013

The Anatomical Record

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The limb bones of an elephant are considered to experience similar peak locomotory stresses as a shrew. "Safety factors" are maintained across the entire range of body masses through a combination of robusticity of long bones, postural variation, and modification of gait. The relative contributions of these variables remain uncertain. To test the role of shape change, we undertook X-ray tomographic scans of the leg bones of 60 species of mammals and birds, and extracted geometric properties. The maximum resistible forces the bones could withstand before yield under compressive, bending, and torsional loads were calculated using standard engineering equations incorporating curvature. Positive allometric scaling of cross-sectional properties with body mass was insufficient to prevent negative allometry of bending (F b ) and torsional maximum force (F t ) (and hence decreasing safety factors) in mammalian (femur0.89 ) with the exception of avian femoral F b and F t . The minimum angle from horizontal a bone must be held while maintaining a given safety factor under combined compressive and bending loads increases with M b , with the exception of the avian femur. Postural erectness is shown as an effective means of achieving stress similarity in mammals. The scaling behavior of the avian femur is discussed in light of unusual posture and kinematics. Anat Rec, 296:395-413,

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Terrestrial locomotion in monotremes (Mammalia: Monotremata)

Cited by 44 publications

References 15 publications

An evolutionary perspective on the walking gait of the long‐beaked echidna

An evolutionary perspective on the walking gait of the long‐beaked echidna

Abdominal muscle function in ventilation and locomotion in new world opossums and basal eutherians: Breathing and running with and without epipubic bones

The Role of Cross‐Sectional Geometry, Curvature, and Limb Posture in Maintaining Equal Safety Factors: A Computed Tomography Study

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