Its apothecia (fruiting bodies) are circular, up to 4.5 mm in diameter, with the disc evolving from concave to slightly convex and coloured from orange-brown to red-brown, surrounded by a thick, prominent margin.

The lichen was described as new to science in 2011 by the lichenologists Helge Thorsten Lumbsch, Alifereti Naikatini, and Robert Lücking.

The type specimen was collected in Fiji, specifically along the access road to the summit of Devo Peak on Taveuni.

Individual ascospores of Megalospora austropacifica are clear and two-celled, with a slight curve reminiscent of the sulphurata-type spores.

Initially, Megalospora sulphurata was broadly defined by Sipman in 1983, but subsequent studies by Ludmilla Untari in 2006[3] led to the differentiation of additional species within this complex.

[1] At the time of its original publication, Megalospora austropacifica had been identified exclusively on the Fijian islands of Taveuni and Viti Levu.

In these locations, it typically grows in montane forests, both relict and secondary, where it is found on tree bark.