Fissurina nicobarensis

The lichen's body (thallus) is a yellowish-brown, glossy crust dotted with small warts. Rising from this surface are many branched, slit-like fruiting bodies called lirellae (a type of ascocarp); each lirella is 1–10 mm long, slightly emergent, and belongs to the globulifica-type, characterised by semi-emergent, often branched lirellae and a thin, pale, non-carbonised exciple that is overlaid by the thalline margin. The lirellae's wall (exciple) is thin, pale orange-brown and lacks the black carbonised layer found in some relatives.^[2]

Inside, a clear hymenium (the spore-producing layer) stands 62–87 micrometres (μm) tall. Each ascus contains eight colourless ascospores that are submuriform—divided by several cross-walls and one or two longitudinal walls, giving a brick-like appearance—and measure 10–15 μm long by 6–7 μm wide. Every spore is wrapped in a thin gelatinous halo. No lichen secondary metabolites were detected with standard spot tests or thin-layer chromatography.^[2]

The species is known to occur only on Great Nicobar Island in the southern Nicobar group (India). It inhabits humid lowland rainforest, growing on the bark of living trees in shaded, wet conditions.^[2]