Patterns of hindlimb segment growth in various lizards and their relation to lizard ecology

BERGMANN, Philip J *; RUSSELL, Anthony P: Patterns of hindlimb segment growth in various lizards and their relation to lizard ecology.

Although numerous functional morphological studies have treated the lizard hindlimb as a unitary structure, correlating its length with numerous performance and ecological variables, a few more recent approaches have accommodated for the segmental nature of the limb. Here, growth of the thigh, crus, metatarsus, and fourth toe of the hindlimb of a number of lizard species with divergent locomotor patterns and ecological contexts is modeled using principal component analysis. Results are then compared to predicted positive allometry of the thigh, and to allometric patterns observed in other taxa. Growth rates varied between limb segments, with the general pattern of crus > thigh > fourth toe > metatarsus being demonstrated. The two most proximal segments of the hindlimb grow more rapidly than the distal most pair. The fossorial Scincus scincus was characterized by a faster growing thigh and slower growing fourth toe than other taxa, while the bipedal sand dwelling Callisaurus draconoides had a far slower growing thigh segment. The ways in which differential segmental hindlimb growth might influence our understanding of ecomorphology is discussed.

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