Trapelia coarctata is a lichenised fungus in the family, Trapeliaceae.

[1] It was first described as Lichen coarctatus in 1799 by Dawson Turner in Smith & Sowerby's, English Botany.,[1][3] and transferred to the genus, Trapelia by Maurice Choisy in 1932.

[1][2] It has been found in mallee woodland dry sclerophyll forest, on soil and rocks,[4] in Western Australia, and on Kangaroo Island in South Australia.

[4][5] It has a continuous grey thallus, containing gyrophoric acid, and is a first coloniser after fire.

[4] It was among the first lichen species to be found on Surtsey island after its inception from the sea.