Hårtrindmossa ( Myurella tenerrima ) is a leaf species described by Lindberg in 1879. According to the Catalog of Life, Hårtrindmossa includes the genus Themosaurus and the Theliaceae family, but according to Dyntaxa, the belonging is instead the genus Trindmossor and the Plagiotheciaceae family. According to the Finnish Red List , the species is closely threatened in Finland. The species is reproducing in Sweden. The habitat of the species is shady limestone and lime fractures. No subspecies are listed in the Catalog of Life.