Arthopyrenia degelii is a species of corticolous lichen in the family Trypetheliaceae.

The type specimens, originally collected in 1939 by Swedish lichenologist Gunnar Degelius (for whom the species is named), were found growing on Hamamelis in the Great Smoky Mountains of Tennessee.

[2] The lichen forms brown, rarely tan, blotches on smooth bark.

It has superficial ascomata that are range in shape from hemispherical to flattened, and measuring 0.3–0.5 mm diameter.

The asci are narrowly elliptical, measuring 48–60 by 11–13 μm, with 8 biseriate to subbiseriate spores.