A survey of Desmids (Zygnematophyceae, Charophyta) in Lake Sentarum National Park, West Kalimantan, Indonesia: new records, rediscovered endemics, and a nomenclatural note

This study presents a comprehensive survey of desmids (Zygnematophyceae) from Lake Sentarum National Park (LSNP), West Kalimantan, Indonesia, representing the first dedicated assessment of this group in the area since the mid-20th century. A total of 62 taxa of Desmidiales were documented, comprising 15 genera within the families Closteriaceae, Desmidiaceae, and Mesotaeniaceae. Of these, 34 taxa (54.8%) constitute new distribution records, including 21 species newly recorded for Indonesia and 13 for Kalimantan. One new form, Euastrum longicolle f. oenpelliense Adam & Prabowo, is proposed to replace an illegitimate later homonym. The study also confirms the persistence of two Indonesian endemic taxa, Micrasterias anomala var. kalimantana and M. quadridentata var. indonensiensis, originally described from the region over six decades ago. These findings significantly expand current knowledge of desmid diversity and distribution in Indonesia and highlight LSNP as an important centre of freshwater microalgal biodiversity within tropical peat swamp ecosystems.