[2] The genus was circumscribed in 1950 by the Norwegian lichenologist Eilif Dahl, with Thallinocarpon pulvinatum assigned as the type, and at the time, only species.

This lichen plays a role in the Thallinocarpo nigritelli-Anemum tumidulae association, where it achieves considerable coverage of up to 10%.

Its presence is not limited to Ukraine, as it has also been observed in similar communities in the Czech Republic, indicating a broader geographical distribution.

T. nigritellum grows in the dry, rocky areas just above the normal water level along riverbanks, often in association with other lichen species such as Anema tumidulum, A. nodulosum, and Staurothele frustulenta.

The occurrence of T. nigritellum serves as a key differentiating factor for its namesake association, and is an indicator species for these specific limestone cliff habitats in Eastern Europe.