title: Ontogenetic scaling of the hindlimb muscles of the greater rhea (Rhea americana).
abstract: The greater rhea (Rhea americana) is the largest South American bird. It is a cursorial, flightless species with long powerful legs and reduced forelimbs. The goal of this study was to explore how hindlimb muscles scale with body mass during postnatal growth and to analyze whether the specialized locomotion of this species affects the growth of muscle masses. The mass of 19 muscles and body mass were weighed in 21 specimens ranging from 1-month-old individuals to adults. Seventeen muscles scaled with positive allometry with respect to body mass, whereas two muscles scaled isometrically. The predominance of positive allometric growth in hindlimb muscles results in a limb with massive and powerful muscles specialized to support a large body mass and to attain relatively high running speeds. Analysis of muscle mass scaling is a simple and useful way to compare possible differences between locomotor styles, and it is valuable in studies that reconstruct the paleobiology of extinct taxa.
authors.affiliation: División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo-Universidad Nacional de La Plata, Paseo del Bosque s/n, La Plata, B1900FWA, Buenos Aires, Argentina.|CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas.
authors.forename: M B J
authors.initials: MB
authors.lastname: Picasso
mesh_terms: D000818:Animals; D004210:Dissection / Q000662:veterinary*; D006614:Hindlimb / Q000033:anatomy & histology* / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology; D020311:Rheiformes / Q000033:anatomy & histology*; D012420:Running / Q000502:physiology*; D013020:South America