LAUSR

Abstract The genus Paracladopus was established based on the type species P.chiangmaiensis in 2006. The two Paracladopus species are distributed in Thailand and Laos; however, neither of them has been documented in China to date. During our field work in 2020, we collected a river-weed in Wuzhi Mountain, Hainan Province of China. After checking the morphological characters, it was identified as P.chiangmaiensis. Then, we assembled and annotated its chloroplast genome based on the genome skimming data. The results showed that the complete chloroplast genome was 133,748 bp with 35% GC content, consisting of 76 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. A maximum-likelihood tree constructed based on the matk genes showed that WuMS109 was clustered with P.chiangmaiensis (AB537420, AB698348) without base difference and together with the remains of Paracladopus formed a sister clade to Cladopus. This is the first report of P.chiangmaiensis that represents a new generic record for China. The discovery of this river-weed could lay the foundation for investigating their biogeographical patterns and species evolution in further studies.