Tephromela superba

Tephromela superba forms a thin thallus (the main body of the lichen) that is creamy white, sometimes with a slight yellowish or pinkish tinge. This thallus is typically up to 0.5 mm thick and spreads across the substrate with a thin, blackish prothallus (an advancing edge of fungal hyphae) at its margin. The surface appears cracked into small, flat, smooth areas called areoles that measure about 0.5–1.2 mm across. The thallus lacks a true cortex (protective outer layer) and has minute mineral inclusions in its medulla (inner layer).^[2]

The reproductive structures (apothecia) are quite distinctive in T. superba. They are initially attached to the thallus but become slightly raised as they mature. These apothecia are blue-black in colour, circular, and notably large (1.2–5.0 mm in diameter). The disc-shaped surface of each apothecium is slightly convex to almost hemispherical and often irregularly cracked. Young apothecia may have a thin thalline margin (a rim of tissue containing algal cells), but this becomes excluded in mature specimens.^[2]

Microscopically, T. superba has a tall hymenium (spore-producing layer) measuring 120–250 μm, with septate paraphyses (sterile filaments) that have a gelatinous sheath and are not or only slightly swollen at the tips. The hymenium contains purple pigment (described as "atra-red" in technical literature). The hypothecium (tissue beneath the hymenium) is distinctive with a golden brown lower section and a hyaline (colourless and transparent) upper layer that is unusually wide (50–80 μm). The spores are simple, colourless, thin-walled, and measure 12–13 by 8–10 μm.^[2]

Chemically, the lichen contains atranorin and α-collatolic acid, sometimes with alectoronic acid and traces of physodic acid.^[2]

Tephromela superba has a distribution that encircles the polar regions of the Southern Hemisphere, occurring in multiple landmasses surrounding Antarctica. This circumsubpolar pattern means the species is found in various locations that form a rough ring around the Antarctic continent, including southern South America (Tierra del Fuego, Argentina, southern Chile), the Falkland Islands, Campbell Island in the New Zealand Subantarctic Islands, and parts of Antarctica itself.^[2]

The species seems to prefer rocky substrates in exposed, cold environments. Collection sites include mountain summits, alpine regions, and feldmark landscapes (a vegetation type characterized by scattered cushion plants, lichens, and mosses growing in harsh, windswept terrain). Specimens have been found at elevations ranging from sea level to around 640 m (2,100 ft).^[2]