ABSTRACT
Fungal pathogens of reptiles are commonly diagnosed, with Aphanoascella galapagosensis known to affect Galapagos giant tortoises (Chelonoidis spp.), although the implications of this fungus for the health and well-being of these unique species remain understudied. Therefore, the goal of this study was to explore health and environmental variables that may be associated with white shell lesion coverage associated with A. galapagosensis in free-living Galapagos tortoises. For 200 western Santa Cruz tortoises (Chelonoidis porteri) and 70 Alcedo tortoises (Chelonoidis vandenburghi), the percentage of fungal lesion coverage was calculated based on images taken from six different projections per individual, including the carapace and plastron. White lesion shell coverage was compared between species and correlated with hematology and blood chemistry parameters, season, elevation, shell integrity (i.e., scratches, lesions, and fractures), and land-use type. A higher percentage of carapacial fungal white lesion coverage was found in western Santa Cruz tortoises (3.3%) than Alcedo tortoises (0.055%). In both species, a positive correlation was found between fungal white lesion coverage and lymphocyte counts. In addition, tortoises sampled in more humid areas had a higher prevalence of fungal coverage. This study indicates that fungal coverage may be influenced by environmental factors and may affect the overall health status of critically endangered Galapagos giant tortoises.