New species of Septobasidium from southern Costa Rica and the southeastern United States

Abstract

New species are described in Septobasidium, a genus of urediniomycete parasites on scale insects. One new species, S. gomezii, is described from Costa Rica, and another, S. meredithiae, is described from Louisiana. S. gomezii is most similar to S. septobasidioides, but macroscopic and microscopic differences support it being a distinct species. S. meredithiae is similar to S. alni and S. castaneum but differs from these species in several macroscopic and microscopic characters, especially when the species are observed on the same host tree and insect species. Another species collected only once in Costa Rica is listed with observations but it is not formally described here. This Septobasidium species shares some key characteristics with S. ramorum but combines a dense, compact, nearly black thallus and pigmented probasidia-like structures with spindle-shaped haustoria. Implications for taxonomy, morphological evolution and host specificity in Septobasidium are discussed.

• coccoidea
• gomezii
• Melanaspis
• meredithiae
• urediniomycetidae

I am grateful to Luis Diego Gomez and Meredith Blackwell for letting me use their names and for providing their helpful advice, guidance, enthusiasm and mycological expertise. I thank Rebecca Yahr, Carla Rydholm, Tim James, Jeri Parrent, Cindy Henk and two anonymous reviewers for helpful comments related to this manuscript; Cecile Gueidan for assistance in preparing sections and Bill Burk for help with herbarium material and literature. I also thank these people for their assistance and support of field collecting and culturing: Rytas Vilgalys, Shannon Henk, Juan Luis Mata, William Henk and Sung-Oui Suh. This research was supported by Andrew W. Mellon Foundation fellowships from the Organization for Tropical Studies and Duke University.