The Genus Coscinodon (Bryopsida, Grimmiaceae) in South America, including a New Species

Abstract

Three species of the moss genus Coscinodon (Grimmiaceae) are recognized from South America. Coscinodon pseudocribrosus is here described as new. All three species are en- demic to the Andes. Coscinodon trinervis is retained in Coscinodon. In 1903, R. S. Williams described Grimmia tri- nervis based on specimens that he had collected near Juliaca, Peru while on an expedition to study the upper reaches of the Amazon in Bolivia. In 1916, Brotherus (in Herzog 1916) transferred this species to the genus Coscinodon and reported sev- eral additional collecting sites in Bolivia. Further, he described a second species, Coscinodon bolivi- anus, at that same time. The type locality of C. bolivianus is near Huaillattanisee, Bolivia. These were the first records of this genus in South Amer- ica. Subsequently no further species of Coscinodon have been described from the continent. Few col- lections have been made of the genus and most re- search has focused on transferring species from Coscinodon to Grimmia (Deguchi 1987; Hermann 1976) or synonymizing these species with other more common Coscinodon species (Churchill 1981). During the course of a revisionary study of the genus Coscinodon, I investigated these South American specimens. The purpose of this paper is to clarify the concepts of the species that are found in South America by providing descriptions of the two known species and one species described new here. Further, there has been confusion of species concepts due to the unfortunate coincidence of hav- ing a number of species, including superficially similar members of the genus Grimmia, in the type packages of at least one of the Coscinodon species. This has led to mistakes about the relationships of the species.