CRUSTIFILUM (COLEOFASCICULALES): A NEWLY RECORDED GENUS OF DESERT CRUST CYANOBACTERIA IN CHINA AND TAXONOMIC INSIGHTS INTO RELATED GENERA

To advance the development of a monophyletic toxonomy system for modern cyanobacteria, two strains of filamentous cyanobacteria, CHAB7530 and CHAB7535, were isolated and purified from soil crust samples in Shapotou Nature Ecological Reserve, Ningxia Hui Autonomous Region, China. These strains exhibited morphologically similarities to the Coleofasciculus-like and Microcoleus-like species. Analysis based on 16S rRNA gene sequences identified CHAB7530 and CHAB7535 as belonging to Crustifilum hispaliculae Moreira-Fernandes, Giraldo-Silva, D. oush & Garcia-Pichel 2021, with 99.7%—99.9% similarity in their sequences. Phylogenetic analyses showed that they clustered within Crustifilum and formed a well-supported evolutionary clade. Additionally, supplementary ITS secondary structure data for this species were provided. The integration of molecular, morphological, and ecological data using a polyphasic approach indicates that CHAB7530 and CHAB7535 were C. hispaliculae, which were represent new records for China. The article also discusses taxonomic revisions and proposals for certain genera previously separated from the Microcoleus steenstrupii complex (e.g. Parifilum) based on the results of phylogenetic analyses.