Coniarthonia haematodea

The body (thallus) is a thin, whitish crust that develops within the uppermost layers of the bark. The green algal partner (photobiont) is sparse and consists of Trentepohlia cells (about 15–25 × 8–10 μm) arranged in long chains.^[2]

The fruiting bodies (ascomata) are scattered and partly protruding from the bark (erumpent), usually roundish and spot-like (sometimes slightly elongated and aligned with the bark fibres), about 0.48–2.6 mm across and 130–180 μm thick in cross-section. They are convex and densely frosted with dark red pigment (pruinose); a distinct outer wall (excipuloid layers) is not evident. The uppermost tissue layer (epithecium) is water-repellent (hydrophobic) and densely packed with crimson to violet pigment crystals (without a colorless fraction), and the spore-bearing layer (hymenium) also contains abundant crimson crystals. The asci are nearly spherical (subglobose), stalked, and each contains eight ascospores. The ascospores are persistently colorless (hyaline), smooth, divided into 6 cells (5-septate), and measure about 27–36 × 10–13 μm.^[2]

Chemically, the reddish pigments dissolve in K (K+ orange-red), and Grube reported a violet pigment (Hae1) along with several purplish pigment fractions (Hae2, Pyr1–Pyr3) and an additional trace pigment based on thin-layer chromatography.^[2]

Coniarthonia haematodea is a lichen-forming fungus species that occurs on bast (inner bark tissues). Grube noted that, based on the type specimen, it appears to be poorly lichenized, consistent with the very sparse photobiont.^[2]

The species is known only from the type locality in Bahia, Brazil. It is similar to C. pyrrhula in ascospore characters, but differs by having larger, spot-like ascomata and fewer ascospore septa.^[2] As of 2025, it had not been reported elsewhere in Brazil.^[3]