Miniaturization, genome size, and biological size in a diverse clade of salamanders

Genome size (C-value) can affect organismal traits across levels of biological organization, from tissue complexity to metabolism. Neotropical salamanders show wide variation in genome and body sizes, including several clades with miniature species. Because miniaturization imposes strong constraints on morphology and development, and genome size is strongly correlated with cell size, we hypothesize that body size has played an important role in the evolution of genome size in bolitoglossine salamanders. If this hypothesis is correct, then genome size and body size should be correlated in this group. Using Feulgen Image Analysis Densitometry (FIAD), we estimated genome sizes for 60 species of neotropical salamanders. We also estimated the “biological size” of species by comparing genome size and physical body sizes in a phylogenetic context. We found a significant correlation between C-value and physical body size using optimal regression with an Ornstein-Uhlenbeck model, and report the...