Cystinarius: phylogeny and species diversity in China

Cystinarius is a small genus belonging to the family Cortinariaceae, distinguished by its distinctive combination of small basidiospores and presence of both cheilo- and pleurocystidia, a combination that is rarely found in other genera within the Cortinariaceae. To date, this genus consists of only two subgenera and includes seven recognized species. Previously, only a single specimen of Cy. crassus was reported from China. Based on the analysis of 17 newly collected specimens, supported by morphological evidence and two-locus phylogenetic inference, five species, namely, Cy. fulvellus, Cy. longipes, Cy. shennongensis, Cy. crassus, and Cy. paurigarhwalensis, were recognized. Among them, the former three species are new to science, whereas the last one is new to China. This study provides comprehensive taxonomic descriptions and a detailed identification key to the Cystinarius species discovered in China.

丝膜菌属（Cystinarius）是隶属于丝膜菌科（Cortinariaceae）的小型类群，其鉴别特征为兼具小型担孢子（basidiospores）与缘囊体（cheilocystidia）、侧囊体（pleurocystidia）的独特组合——该特征组合在丝膜菌科的其他类群中极为罕见。迄今为止，该属仅包含2个亚属，已被正式认可的物种共计7种。此前，中国仅报道过厚边丝膜菌（Cy. crassus）的单份标本。本研究基于17份新采集标本的形态学证据与双基因座系统发育分析，确认了5个物种，分别为Cy. fulvellus、Cy. longipes、Cy. shennongensis、Cy. crassus与Cy. paurigarhwalensis。其中前3个物种为科学界新发现类群，最后1个为中国新记录物种。本研究为中国境内发现的丝膜菌属物种提供了全面的分类学描述与详细的鉴定检索表。