Juliomys ossitenuis is a species of rodent in the family Cricetidae native to South America.

They are found in the Phylum Chordata, Class Mammalia, and Order Rodentia.

[3] They can survive in habitats that accumulate heavy amounts of rain.

[2] Three types of hair are present in the dorsal region of this species' fur: aristiform, setiform and villiform.

[3] The ventral coat is maize yellow, paws in dorsal view are light orange (apricot yellow and dark orange), tail is smooth and intensely bi-colored dorsoventrally, presence and absence of tufts of hair at the tip of the tail, and ventral coat banding pattern, with a gray base corresponding to approximately half and one third of the coat length.