Arctomia teretiuscula is a rare species of squamulose (scaly) lichen in the family Arctomiaceae.

The type specimen was collected by Walter Obermayer in Haigoulou glacier and forest park (Mount Gongga) at an altitude between 2,980 and 3,150 m (9,780 and 10,330 ft); here it was found growing on mossy rocks and soil.

Although at the time of publication the lichen was only known to occur at the type location, Jørgensen speculates that it may have a wider distribution in similar habitats in the Himalayas.

[1] The lichen forms dark brown squamulose rosettes up to 1 cm (0.4 in) in diameter.

Its ascospores, which number 8 per ascus, are spindle-shaped (fusiform) and often curved, divided by 6 to 8 septa, and measure 40–60 by 4–5 μm.