Two new species of Perichaena (Myxomycetes) from arid areas of Russia and Kazakhstan

Abstract

Two new myxomycete species from dry steppe and desert communities of the Caspian Lowland (Russia) and central Kazakhstan are described and illustrated. They are placed tentatively within genus Perichaena, which does include species with a reduced capillitium and single-layered peridium. Both species were found repeatedly in moist chamber cultures; P. heterospinispora appeared on leaf litter and twigs, whereas P. polygonospora occurred on leaf litter and weathered dung of rodents. Both species have spore ornamentation that is unique for members of genera Licea and Perichaena. The spore ornamentation of the first species includes scattered large, pyramid-like spines 0.9–1.2 μ m high that sometimes have enlarged ends. Among these spines the spore surface is covered by evenly and densely distributed warts that are visible only by SEM. The second species is characterized by angular spores with a coarse network of rounded ridges. The areas among these ridges bear scattered composite warts 0.3–0.5 μ m high that sometimes coalesce to form clusters but more often are distributed evenly and densely and are visible only by SEM. The stability of the taxonomic characters of both species was confirmed by several collections from different regions obtained in 2 y. The morphology of the fructifications of the two myxomycetes was examined with both scanning electron and light microscopy, and micrographs of all relevant features are presented.

• deserts
• moist chamber culture
• Mycetozoans
• slime molds
• steppe
• taxonomy

We are grateful for SEM support provided by Ludmila A. Kartzeva, St Petersburg (Komarov Botanical Institute RAS), as well as advice on the classification of vegetation by I.N. Safronova (Komarov Botanical Institute RAS) and A.V. Popov (State Pedagogical Volgograd University). We are very grateful for the Latin diagnosis by Dr A. Borodina. Expeditions to the Caspian Lowland and laboratory studies were supported financially in part by the Planetary Biodiversity Inventory Project (Global Biodiversity of Eumycetozoans, grant DEB-0316284 from the U.S. National Science Foundation) and the Russian Foundation for Basic Research (grant 07–04–00353-a) and “Bioraznoobrazie” from the Russian Academy of Science.