Asterothyrium vezdae is a species of foliicolous (leaf-dwelling) lichen in the family Gomphillaceae. It is found in Bolivia, where it grows on the leaves of vascular plants in the Amazon rainforest. The lichen is distinguished from its closest relative, Asterothyrium octomerum, by the larger number of septa in its, and its and black apothecia.
Asterothyrium vezdae was described as a new species in 2008 by Adam Flakus and Robert Lücking. The type specimen was collected by the first author in Nuevos Reyes village (José Ballivián Province, Beni Department) at an altitude of 190m (620feet). The species epithet honours Czech lichenologist Antonín Vězda, "for his numerous and significant contributions to the study of foliicolous lichens world-wide".
The thallus of Asterothyrium vezdae is (growing on the upper leaf surface), forming rounded to irregular patches that are 1–2 mm in diameter, with a thickness of 20–30 μm. The entire thallus can measure 3–5 mm across and has a smooth, white surface comprising colourless, rectangular cells. Its is .
The apothecia are typically single on each thallus patch, and in form but with a outer margin. They are rounded and measure 0.3–0.6 mm in diameter and 100–180 μm in height. The is plane, with a yellow-brown to dark brown colour, while the margin is thick, strongly prominent, and divided into irregular lobes. The is, and the is colourless to pale brown. The hymenium is colorless, while the is yellow-brown. Asci have an ellipsoid to ovoid shape, while are oblong to, and have from 7 to 15 septa with slight constrictions at the septa. A. vezdae the first species in genus Asterothyrium known to have up to 15-septate spores. are and conical, with a triangular base, while are oblong-ellipsoid and lack septa.
Asterothyrium octomerum, found in tropical Africa, has spores similar to A. vezdae, but these spores only contain 7 septa that do not have constrictions. Additionally, A. octomerum has brownish-grey, rather than black apothecia.
At the time of publication, Asterothyrium vezdae was known only from the type locality in the lowland southwest Amazon forest of Bolivia, where it was found growing on the leaves of a vascular plant. The chemical composition of this species has not been tested.