Biodiversity of myxomycetes in subantarctic forests of Patagonia and Tierra del Fuego, Argentina

A biodiversity survey for myxomycetes was carried out in Patagonia and Tierra del Fuego (Argentina) in late January and early February 2005. Specimens were collected from six National Parks, located in five different provinces between 39° and 55°S latitude. Nothofagus forests represented the primary vegetation type investigated, but Valdivian temperate rainforests also were included in the survey, as were coniferous forests dominated by species of Araucaria, Astrocedrus and Fitzroya. More than four hundred (442) specimens of myxomycetes representing 67 different species in 23 genera were collected either in the field, or from moist chamber cultures prepared with samples of bark and litter obtained from the same collecting sites. The total species list generated from both the field and laboratory components of the survey includes six new records for South America and 13 new records for Argentina. Two species of the genus Diderma, D. gracile and D. robustum, described originally from Tierra del Fuego 35 years ago and not reported since, were among the more interesting collections. A third species of the genus, D. antarcticum, found only once since its description in 1887, was found for the third time in the world during the survey. These collections were compared to the type material deposited in La Plata, Argentina (LPS) and the first photographs of these species by LM and SEM are included. Ecological comments are made on how macroenvironmental factors as well as microhabitats, influence patterns of myxomycete distribution.