Neoprotoparmelia australisidiata

The lichen forms a crust of almost touching, flat to slightly convex areoles up to about 0.7 mm across and 0.1 mm thick. Surfaces are somewhat shiny and vary from pale brown to dark brown, occasionally showing olive-green or olive-grey tints; at the margins a thin black prothallus may be present but is often inconspicuous. Each areole carries clusters of minute, cylindrical isidia that remain 0.07–0.10 mm wide along their length and may reach 0.9 mm tall. These propagation bodies are frequently once, and sometimes repeatedly, branched and can appear knobbly; they share the thallus colour and do not develop darkened tips.^[1]

Fruiting bodies are rare and only immature apothecia have been seen: they are sessile, round, 0.4–0.6 mm in diameter, with a glossy orange-brown disc that is level to slightly concave. The narrow margin stands is slightly raised above the disc and has the same glossy brown colour. Internally, the spore-bearing layer (hymenium) is colourless and up to 50 μm high, while the supporting tissues are likewise hyaline; paraphyses are branched and slender, and mature asci and ascospores have yet to be observed. Chemical spot tests give KC+ (pink) and UV+ (greenish-white) reactions, indicating the presence of alectoronic acid (major), with dehydro- and β-alectoronic acids in minor to trace amounts, a profile typical for several members of the genus.^[1]

The species is corticolous, growing on the bark of hardwood trees in open or closed forest. Confirmed records are restricted to Australia, with collections from the Top End of the Northern Territory and from far-south coastal New South Wales.^[1] Field notes suggest it tolerates both seasonally dry tropical woodland and temperate sclerophyll forest, provided the substrate remains intermittently moist and exposed to filtered light.^[1]