Pyrenula rubroanomala
Pyrenula rubroanomala is a bark-dwelling crustose lichen from the Pyrenulaceae family. It was described in 2008 by Aptroot and Lucking from specimens collected in Palo Verde National Park, Costa Rica. The thallus is thick and pale ochraceous yellowish-gray, often with a dusty white coating, and can form patches up to about 2 cm across. The fruiting bodies (perithecia) are small black bumps on the surface; several of these fuse into irregular clusters about 1–2 mm wide, giving a dark, melanothecioid look. The clusters are covered by a thin red pigment, which turns purple in potassium hydroxide.
Under the microscope, the hamathecium is clear and the asci contain eight gray-brown ascospores that are distoseptate and about 15–17 by 5–6 μm. The thallus is UV–, while the red pigment reacts to KOH (K+ turns it purple), indicating an anthraquinone pigment.
The lichen grows on tree bark on lower trunks in moist, secondary forest and open secondary vegetation at around 10 m elevation. It’s notable as the first strongly melanothecioid Pyrenula with a red pigment. It resembles Pyrenula anomala in spore and perithecial structure, and its pigment is similar to Pyrenula cruenta/cruentata. In Costa Rica, it has been found alongside other bark-dwelling lichens such as Pyrenula anomala, Trypethelium ochroleucum, and Glyphis substriatula. The holotype is kept at the Field Museum's herbarium.
This page was last edited on 3 February 2026, at 17:09 (CET).