Endemism in the genus Pertusaria (Pertusariales, lichenized Ascomycota) from the Galapagos Islands

Abstract

This revision of Pertusaria in the Galapagos Islands documents twenty-four species, twenty-two being new to the archipelago. Secondary chemistry correlates well with morphology and anatomy and is particularly useful in distinguishing these taxa. Eight species are described as new to science, and seven are known only from the Galapagos: Pertusaria albineoides, P. cerroazulensis, P. darwiniana, P. medullamarilla, P. stictica, P. thioisidiata and P. xanthoisidiata. Pertusaria lueckingii is new, but it also occurs in Central America (El Salvador). Three new endemic varieties are described based on their chemistry: Pertusaria thioisidiata var. isidiogyrophorica, P. tejocotensis var. stictica and P. xantholeucoides var. thamnolica. In contrast with previous studies on other genera where rates of endemism of 8–10% were observed, in Pertusaria 30–37% of all species and 41–46% of all taxa are considered endemic.