Two new species of Astrothelium from Sud Yungas in Bolivia and the first discovery of vegetative propagules in the family Trypetheliaceae (lichen-forming Dothideomycetes, Ascomycota)

Two new species of Astrothelium are described from the Yungas forest in Bolivian Andes. Astrothelium chulumanense is characterised by pseudostromata concolorous with the thallus, perithecia immersed for the most part, with the upper portion elevated above the thallus and covered, except the tops, with orange pigment, apical and fused ostioles, the absence of lichexanthone (but thallus UV+ orange-yellow), clear hamathecium, 8-spored asci and amyloid, large, muriform ascospores with median septa. Astrothelium isidiatum is known only in a sterile state and produces isidia that develop in groups on areoles, but easily break off to reveal a medulla that resembles soralia. Both species, according to the two-locus phylogeny, belong to Astrothelium s.str. The production of isidia is reported from the genus Astrothelium and the fam-ily Trypetheliaceae for the first time.

Automated summary

This article describes two new species of Astrothelium, namely Astrothelium chulumanense and Astrothelium isidiatum, which are found in the Yungas forest in the Bolivian Andes. Astrothelium chulumanense is characterized by concolorous pseudostromata, partially immersed perithecia with an elevated upper portion covered in orange pigment, fused ostioles, absence of lichexanthone (but thallus UV+ orange-yellow), clear hamathecium, 8-spored asci with amyloid, and large, muriform ascospores with median septa. Astrothelium isidiatum is only known in a sterile state, producing isidia that develop in groups on areoles and resemble soralia when broken off. Both species belong to the Astrothelium s.str. according to the phylogenetic analysis. The production of isidia is reported for the first time in Astrothelium and the family Trypetheliaceae.