It is found in southern Ukraine, where it parasitises the foliose lichen Cetraria aculeata growing on sand dunes.

The fungus was formally described as a new species in 2018 by Ave Suija, Valeriy Darmostuk, and Alexander Khodosovtsev.

The species epithet honours Estonian lichenologist and botanist Hans Trass,[1] Didymocyrtis trassii has pycnidial conidiomata of the Phoma-type.

[1] Didymocyrtis trassii is only known to occur in southern Ukraine, and it only parasitises Cetraria aculeata growing on sand.

The fungus grows on the lower branches of the thick cushions of the lichen, and does not appear to cause damage to the host.