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Terrestrial animals in global wet-dry tropical ecosystems experience year-round high temperatures but concentrated summer rainfall. This highly seasonal precipitation is expected to have major evolutionary and ecological consequences for animals. We considered how strong seasonal patterns of rainfall might influence the environment and biological attributes of the world's largest predatory lizard, the Komodo dragon (Varanus komodoensis). We predicted that annual variation in rainfall or temperature may influence the seasonal phenology of vegetation, and in turn, the phenology of Komodo dragon reproduction and hatchling emergence. Similarly, seasonal environmental differences may affect Komodo dragon rates of somatic growth, body condition, survival and daily movement. Our results indicated evidence of strong seasonal variation in mean monthly rainfall and leaf area index for open deciduous forest and closed dense forest. These environmental variables were significantly correlated with female Komodo dragon nesting activity and hatchling emergence. Neither Komodo dragon somatic growth rate nor body condition exhibited seasonal differences. There was, however, increased daily movement rates of Komodo dragons during the dry season. This suggests dry season associated life-history activities or thermoregulatory efficiency might explain increased daily movement. Ultimately, the Komodo dragon showed differential sensitivities in its biology to seasonal environmental variation. [ABSTRACT FROM AUTHOR]

Geometric morphometrics is a powerful tool for the quantification, visualization and analysis of morphological variation and change. This approach is being applied more frequently in a phylogenetic comparative context to assess the relative influence of size, ecology, function, and developmental constraints on morphological evolution. Geometric morphometric methods rely on homologous landmarks as the source of shape data, and the level of detail and accuracy increases with the amount of information contained in a landmark configuration. It may be possible, however, to capture particular elements of shape variation by concentrating on different observation angles of a complex structure like the vertebrate cranium. Our study examines how observation view (dorsal, ventral and lateral) influences 2D geometric morphometric analysis of interspecific cranial shape variation in monitor lizards. We recover a strong phylogenetic signal in all three views and general concordance in patterns of size-corrected shape diversification within the genus. We also find subtle, but important differences, however, among views in analyses of evolutionary allometry and shape variation, which may reflect both landmark configuration design and adaptive functional trends of the study system. Our study shows that studies restricted to a 2D geometric morphometric analysis of a complex 3D biological structure can combine carefully designed 2D landmark configurations describing alternative planes to maximize shape coverage. [ABSTRACT FROM AUTHOR]

The bipedal posture (BP) and gait of humans are unique evolutionary hallmarks, but similar stances and forms of locomotion have had enormous influences on a range of phylogenetically diverse tetrapods, particularly dinosaurs and birds, and a range of mammalian lineages, including non-human apes. The complex movements involved in bipedalism appear to have modest evolutionary origins, and it is presumed that a stable and erect posture is a prerequisite for erect strides and other bipedal movements. Facultative bipedalism in several lineages of lizards is achieved by running... [ABSTRACT FROM AUTHOR]