Trypethelium astroideum
Trypethelium astroideum is a species of corticolous, crustose lichen in the family Trypetheliaceae. It was described as new to science by Adam Flakus and André Aptroot from material collected in lowland Bolivia.
Taxonomy
The species was described from a type specimen collected in 2009 in Noel Kempff Mercado National Park, Santa Cruz Department, Bolivia, where it grew on trees in Moxos Savanna. Its name refers to the star-like appearance of its, created by the arrangement of the fruiting bodies. Trypethelium astroideum is most similar to T. subeluteriae but differs by having pseudostromata containing parietin, an additional rust-red anthraquinone on the outside, partly fused ostioles, and larger, more septate ascospores.Description
The thallus is, with a cortex 40–80 μm thick. It is smooth to somewhat swollen, continuous, somewhat shiny, olive-green, up to 7 cm across, and about 0.5 mm thick. It induces swellings of the host bark but is not surrounded by a black.The are raised, irregular to star-like in outline, 1.0–1.5 × 1–3 mm and about 0.8 mm high, with sloping sides. Their surfaces are similar to or slightly paler than the thallus, bordered paler, and contain black ostiolar areas overlaid with rust-red pigment. Internally they contain orange granular pigment and parietin, embedded in bark tissue. The ascomata are pear-shaped, 0.3–0.6 mm in diameter, aggregated within the pseudostromata. Their walls are fully, not layered, and up to 100 μm wide. Ostioles are mostly fused, eccentric to apical, convex, and black, each surrounded by a rust-red pigmented spot that often forms a star-shaped pattern. The is clear. The asci contain eight spores each. The ascospores are colorless, spindle-shaped, with rounded ends, divided by 12–22 septa, and measure 65–100 × 11–14 μm. They have rounded and no gelatinous sheath. Pycnidia have not been observed.
The thallus surface is UV− and K−, and the medulla is K−. The pseudostromata surface is UV−, while the rust-red pigment near the ostioles reacts K+ purple. Inside the pseudostromata, the granular orange pigment reacts K+ carmine red. Thin-layer chromatography detected parietin and an additional unidentified anthraquinone.