Comparative development and ocular histology between epigean and subterranean salamanders () from central Texas.

The salamander clade from the karst regions of central Texas provides an ideal platform for comparing divergent nervous and sensory systems since some species exhibit extreme phenotypes thought to be associated with inhabiting a subterranean environment, including highly reduced eyes, while others retain an ancestral ocular phenotype appropriate for life above ground. We describe ocular morphology, comparing three salamander species representing two phenotypes-the surface-dwelling Barton Springs salamander () and San Marcos salamander () and the obligate subterranean Texas blind salamander () - in terms of structure and size of their eyes. Eyes were examined using confocal microscopy and measurements were made using ImageJ.