Placopsis antarctica

Placopsis antarctica
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Baeomycetales
Family:	Trapeliaceae
Genus:	Placopsis
Species:	P. antarctica
Binomial name
Placopsis antarctica D.J.Galloway, R.I.L.Sm. & Quilhot (2005)

Placopsis antarctica is a species of crustose lichen in the family Trapeliaceae.^[1] It is found only in Antarctica, where it forms pale-coloured, circular patches on rock surfaces, typically 1–3 cm (3⁄8–1+3⁄16 in) across, with distinctive finger-like projections that break down into powdery structures. The lichen contains both green algae and blue-green algae (cyanobacteria) as partners, allowing it to both photosynthesise and convert nitrogen from the air into a form that can be used by other organisms. These circular patches can occasionally grow up to 6 cm (2+3⁄8 in) in diameter, with edges that show neat, fan-like folds and can appear either swollen or slightly flattened.

First described by scientists in 2005, P. antarctica grows on rocks in ice-free areas of the South Orkney Islands, South Shetland Islands, and Antarctic Peninsula, from near sea level up to 550 m (1,800 ft) in elevation. It is one of the first organisms to colonise areas newly exposed by retreating glaciers, helping to establish conditions that allow other species to grow. Studies have shown that the species is sensitive to warming temperatures, suggesting it may be vulnerable to climate change. The species shows particular success on rock surfaces, where it commonly grows alongside other lichens such as Lendemeriella exsecuta, Lepraria neglecta, and Pannaria hookeri.