North American porcupine
"Polytolypa hystricis" is known only from the dung of the North American porcupine, "Erethizon dorsatum". Porcupine dens accumulate thick layers of nutrient-rich dung, hair and urine that are degraded by a succession of fungi. These fungi are disseminated by arthropods (such as insects) or by the porcupine themselves.