The pygmy ringtail possum (Pseudochirulus mayeri) is a species of marsupial in the family Pseudocheiridae. It is found in the montane forest regions of Papua New Guinea and West Papua, Indonesia. They are "widespread along the Central Cordillera" and live at elevations between 1,500 and 3,600 metres (4,900 and 11,800 ft) above sea level.”

Pygmy ringtails are herbivores or “arboreal folivores” that eat pollen, lichen, fungus and “epiphytic moss." P. mayeri also eat the bark of trees, which provides them with calcium and potassium. They have “large incisor” teeth which help with “clipping forage from plants” and have “selenodont molars” that help with “shredding ingested foliage." They have “an enlarged cecum that acts as a fermentation chamber” and allows “gut bacteria to breakdown [sic] plant tissue." The extra retention time allows the pygmy ringtail to obtain more nutrients from the ingested forage.