Varicellaria cacuminum (lichenized Ascomycota, Pertusariales), a new species of lichenized-fungi from Campbell Island/Motu Ihupuku, with notes on Varicellaria and other Pertusariales in New Zealand

The genus Varicellaria was originally erected for a single species that was similar to the species then included in Pertusaria, which all had simple ascospores, but differed in having 1-septate ascospores. However, a molecular analysis has shown that septate ascospores is not a genus-level trait in the group and that Varicellaria was better characterised by the thallus containing lecanoric acid, and several species lacking a septum have subsequently been transferred to Varicellaria from Pertusaria. Here, Varicellaria cacuminum is described as new to science from rocks on the summits of several mountains on Campbell Island/Motu Ihupuku, New Zealand. It is characterised by the thallus lacking soralia, the presence of lecanoric acid, and huge ascospores up to 315 mu m long. The new species is compared with other members of the genus and Pertusaria otagoana, a species with similar sized ascospores. Pertusaria otagoana, which has only been reported from its type locality near Dunedin, is also reported from Campbell Island and South Island, New Zealand. The status of the New Zealand species of Pertusaria transferred to Lepra is discussed and it is concluded that Pertusaria erubescens and P. muricata should be retained in Pertusaria, whereas it is not currently possible to determine the correct generic placement of the other three species.

Automated summary

The genus Varicellaria was originally established for a species with 1-septate ascospores, but later molecular analysis showed that septate ascospores are not a characteristic of the genus. Instead, the presence of lecanoric acid in the thallus is a better distinguishing feature. A new species, Varicellaria cacuminum, was discovered on rocks in Campbell Island, New Zealand, which lacks soralia, contains lecanoric acid, and has large ascospores. Pertusaria otagoana, previously only reported near Dunedin, was also found on Campbell Island and South Island, New Zealand.