Diversity and Distribution of the Saxicolous Lichens, Family Megasporaceae (Pertusariales, Ascomycota) in Southern Xinjiang, China

The Xinjiang Uygur Autonomous Region, also known as Xinjiang, China, is notable for its high diversity and abundance of lichens. The purpose of this study was to examine species diversity and the distribution patterns of saxicolous lichens, family Megasporaceae, which includes the genera Aspicilia, Circinaria and Lobothallia, in Xinjiang Province. Morphology, anatomy, chemical analysis and rDNA-ITS sequences for the species were employed for their identification. As a result, 34 crustose and strictly saxicolous species belonging to three genera were found, which included 22 species of the genus Aspicilia, two of which were new to Xinjiang (A. disjecta (Zahlbr.) J.C. Wei and A. pycnocarpa Q. Ren & Lin Liu), eight common species of Circinaria, as well as four species of Lobothallia, two of which (L. determinata (H. Magn.) T.B. Wheeler and L. pruinosa Kou & Q. Ren) are new provincial records. There was a unimodal pattern with respect to lichen species richness; all specimens of the Megasporaceae family were found between 1600 and 5100 m altitude. The 30 species were collected at altitudes between 2601 and 3100 m; only four species were recorded below 2150 m, and seven were found above 4600 m. As far as the type of rocks are concerned, 24 species were found on siliceous rocks and 10 species were found on calcareous rocks. The 24 lichen species contained seven different secondary metabolites; stictic acid, substictic acid and norstictic acid were more common, whereas aspicilin, constictic acid, lecanoric acid and connorstictic acid were found in only a few lichen species.