Ctenomyces serratus is a keratinophilic fungal soil saprotroph classified by the German mycologist, Michael Emil Eduard Eidam in 1880, who found it growing on an old decayed feather. Many accounts have shown that it has a global distribution, having been isolated in select soils as well as on feathers and other substrates with high keratin content. It has also been found in indoor dust of hospitals and houses in Kanpur, Northern India and as a common keratinophilic soil fungus in urban Berlin. This species has been associated with nail infections in humans as well as skin lesions and slower hair growth in guinea pigs.