The Hindlimb Muscles of <i>Rhea americana</i> (Aves, Palaeognathae, Rheidae)

Picasso, Mariana Beatriz Julieta

doi:10.1111/j.1439-0264.2010.01017.x

Cited by 35 publications

(86 citation statements)

References 20 publications

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“…This is consistent with the findings of Tambussi (1997), who demonstrated through an analysis of athletic capacity rates that some phorusrhacids had the same cursorial capacities as an ostrich. Cursoriality in large-sized birds is achieved with long strides through more elongated hind limbs, whilst smaller sized cursorial birds have shorter hind limbs, but a higher stride frequency (Storer 1971;Gatesy & Biewener 1991;Abourachid & Renous 2000;Picasso 2010). This shows that there is a limitation between size and, secondarily, leg length.…”

Section: Discussionmentioning

confidence: 99%

“…Meanwhile, Patagornithinae and Mesembriornithinae are associated with Rheidae and Casuariidae, which are terrestrial birds with clearly cursorial capacities (e.g., Picasso 2010).…”

Section: Pca and Discriminant Analysismentioning

confidence: 99%

“…This combination is unique to these birds and clearly separates them from aquatic birds (such as Podicipedidae and Gaviidae), which also have a long postacetabular region. Postacetabular extension in phorusrhacids is related to a greater development of the hip extensor muscles (Degrange 2012), which is a feature of birds with cursorial capabilities (Picasso 2010). …”

Section: Pelvis Morphometricsmentioning

confidence: 99%

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Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Degrange¹

2015

Earth and Environmental Science Transactions of the Royal Socie

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The hind limbs of birds have long been considered a key feature in the conquest of different environments. However, the high level of morphological diversity encountered complicates the foundation of a good theoretical correlation between morphology, locomotor habits and substrate preference and this, in turn, complicates palaeobiological interpretations. Phorusrhacids (Aves, Cariamiformes) are a good example, since they have been unequivocally categorised as terrestrial birds due to their reduced forelimbs; and as apex predators with the ability to pursue prey based only on their hind limb morphology. Multivariate techniques (PCA and discriminant analysis), based on traditional metrics and geomorphometrics of the hind limb and pelvis, were applied in order to explore terrestriality and cursoriality in phorusrhacids. Although several groups of birds could be identified, when looking solely at hind limb metrics, some phorusrhacids appear to be associated with walking birds, while others are associated with cursorial birds. However, the pelvis separates cursorial birds and phorusrhacids from walking and wading birds. This scenario is complicated further by a lack of clear definition of the different locomotor modes and substrate preferences in extant birds, and this makes it difficult to confirm phorusrhacid cursoriality based solely on morphometrics. However, some qualitative features of the pelvis and foot make the picture a little clearer. To study limb adaptations in fossil birds, a more holistic study, with an emphasis on qualitative features of the whole posterior locomotor module, is necessary, since morphometrics leaves some issues unresolved. A comparison with the wings is also needed, in order to make a more complete analysis of locomotor behaviour.

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Section: Discussionmentioning

confidence: 99%

“…Meanwhile, Patagornithinae and Mesembriornithinae are associated with Rheidae and Casuariidae, which are terrestrial birds with clearly cursorial capacities (e.g., Picasso 2010).…”

Section: Pca and Discriminant Analysismentioning

confidence: 99%

Section: Pelvis Morphometricsmentioning

confidence: 99%

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Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Degrange¹

2015

Earth and Environmental Science Transactions of the Royal Socie

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“…Given that the flexors and extensors of the intertarsal joint and digits are concentrated on the thigh and shanks segments [72-74], the pedal segments are comprised of predominantly bone, tendon, and integument. In some species, digital extensors are weakly developed [75], and in these taxa these muscles might make minor – though significant – contributions to pedal mass.…”

Section: Discussionmentioning

confidence: 99%

Scale effects and morphological diversification in hindlimb segment mass proportions in neognath birds

Kilbourne

2014

Front Zool

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IntroductionIn spite of considerable work on the linear proportions of limbs in amniotes, it remains unknown whether differences in scale effects between proximal and distal limb segments has the potential to influence locomotor costs in amniote lineages and how changes in the mass proportions of limbs have factored into amniote diversification. To broaden our understanding of how the mass proportions of limbs vary within amniote lineages, I collected data on hindlimb segment masses – thigh, shank, pes, tarsometatarsal segment, and digits – from 38 species of neognath birds, one of the most speciose amniote clades. I scaled each of these traits against measures of body size (body mass) and hindlimb size (hindlimb length) to test for departures from isometry. Additionally, I applied two parameters of trait evolution (Pagel’s λ and δ) to understand patterns of diversification in hindlimb segment mass in neognaths.ResultsAll segment masses are positively allometric with body mass. Segment masses are isometric with hindlimb length. When examining scale effects in the neognath subclade Land Birds, segment masses were again positively allometric with body mass; however, shank, pedal, and tarsometatarsal segment masses were also positively allometric with hindlimb length. Methods of branch length scaling to detect phylogenetic signal (i.e., Pagel’s λ) and increasing or decreasing rates of trait change over time (i.e., Pagel’s δ) suffer from wide confidence intervals, likely due to small sample size and deep divergence times.ConclusionsThe scaling of segment masses appears to be more strongly related to the scaling of limb bone mass as opposed to length, and the scaling of hindlimb mass distribution is more a function of scale effects in limb posture than proximo-distal differences in the scaling of limb segment mass. Though negative allometry of segment masses appears to be precluded by the need for mechanically sound limbs, the positive allometry of segment masses relative to body mass may underlie scale effects in stride frequency and length between smaller and larger neognaths. While variation in linear proportions of limbs appear to be governed by developmental mechanisms, variation in mass proportions does not appear to be constrained so.

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“…obs. ; McGowan, ; Gangl et al ; Picasso, ). This muscle, m. obturatorius medialis, functions as an active tension chord opposing the abdominal muscles.…”

Section: Discussionmentioning

confidence: 99%

The functional role of the ischiopubic membrane for the mechanical loading of the pubis in the domestic fowl (Gallus gallus)

et al. 2012

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Soft tissues other than muscles are supposed to be of mechanical importance, yet they are rarely integrated into finite element models. Here, we investigate the functional role of the ischiopubic membrane for the loading of the pubis of the domestic fowl using 2D finite element analysis. For this purpose, a specimen of the domestic fowl was dissected and soft tissues attaching to the pubis were studied in great detail. Muscles were removed and measurements taken. For the 2D finite element model, the outline was taken from the dissected specimen. Two 2D finite element models were generated: one without and one with ischiopubic membrane. The same muscular loading based on own measurements and electromyographic data was applied to both models. The model without ischiopubic membrane shows anteroventral bending deformation of the scapus pubis, resulting in high compressive and tensile principal stresses at the level of ultimate bone stress values. The model with ischiopubic membrane shows low compressive principal stresses in the pubis consistent with the levels of steady state remodelling of bone. Based on these results, the ischiopubic membrane of the domestic fowl potentially establishes a physiological loading of the pubis and therefore might be of great mechanical significance for the loading of the bone.

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The Hindlimb Muscles of Rhea americana (Aves, Palaeognathae, Rheidae)

Cited by 35 publications

References 20 publications

Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Scale effects and morphological diversification in hindlimb segment mass proportions in neognath birds

The functional role of the ischiopubic membrane for the mechanical loading of the pubis in the domestic fowl (Gallus gallus)

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