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Speckled rattlesnakes (Crotalus mitchellii) inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed...
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We analyzed lizard assemblage structure as a function of elevation in the Bonneville Basin region of the Great Basin Desert using data from visual surveys performed between 2000 and 2003. A total of 1221 lizard observations were recorded, representing eight of the nine species known to occur in the Bonneville Basin. Individual species response curves showed Gaussian and truncated Gaussian distributions for most taxa, and most species demonstrated a nonrandom dispersion of occurrences along the elevation gradient. Nonmetric multidimensional scaling (NMS) revealed hierarchical structuring of lizard species, and strong correlation of NMS axes with elevation provided evidence of uniform lizard community assembly with...
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