[1] This species is characterized its bright red, prominent to sessile growths on tree bark in the rainforests of Rondônia, Brazil.

What makes Pyrenula sanguinea unique are its trypethelioid ascomata—structures housing the reproductive spores—that are fused together, and its brown ascospores (spores) surrounded by a thick, gelatinous sheath with distinctive horn-like appendages.

The ascospores are initially transparent but soon turn brown, with three septa (divisions) and distinctive, gelatinous appendages at both ends that dissolve in a specific chemical solution.

These substances, responsible for the lichen's colouration, do not evaporate upon application of a potassium hydroxide solution (K+), showing a purple reaction.

[2] This species is found on the smooth bark of trees within the primary rainforest of the Cuniã rain forest reserve in Amazonian Rondônia, Brazil.