Hindlimb morphology and locomotor performance in waders: an evolutionary approach

Locomotion performance (measured as stride frequency and stride length) was studied in 16 species of waders. Differences in hindlimb morphology (osteo logy? and myology) were analysed among species. Evolutionary changes in bot h locomotion and morphological variables were analysed using comparative me thods revealing the existence of some ecomorphological patterns relating th ese two sets of characters. Evolutionary changes in stride frequency were c orrelated with changes in the muscles M. iliotibialis cranialis, M. iliotib iales lateralis and hi, gastrocnemius, whereas changes in stride length sho wed correlated evolution with changes in the length of distal segments of t he leg. We identify two different evolutionary strategies in locomotion of waders. One is a change in distal leg segments (skeletal system), an adapti ve modification that increases stride length; the second is a change in the skeletal-muscular system, providing an increase in muscular performance (f orce or speed of contraction) in several muscles, and is an adaptation that increases stride frequency. (C) 1999 The Linnean Society of London.