Phylogenetic Relationships of Grammitid Fern Diversity of Gunung Tama Abu (Sarawak)

Abstract. The forests of Borneo are famous for their plant diversity, but this diversity is seriously threatened. Despite remarkable progress, the taxonomic status and geographic distribution of many species have not been clarified. Here, we explore the use of DNA barcoding to improve not only the recording of local species diversity, but also our understanding of the fern Tree-of-Life. We focused specifically on grammitid ferns collected at Gunung Tama Abu in Sarawak. The four new samples comprised three species of which two were studied using molecular phylogenetics for the first time. These three species were found to be nested in clades corresponding to the established generic taxonomy. The two sampled accessions of Acrosorus streptophyllus formed a sister clade to A. friderici-et-pauli. By increasing the inclusion of Acrosorus species from one to two in the assembled phylogenetic hypothesis, our results provide support to the monophyly of this genus based on DNA sequence data for the first time. The newly sampled Borneo accession of Scleroglossum pyxidatum was sister to a clade comprising accessions of S. sulcatum, whereas the sample of Prosaptia alata formed a clade together with other accessions of this species. In conclusion, DNA barcoding of samples obtained during fieldwork in remote but species rich places enhance the recording of the Tree-of-Life and enable the establishment of reliable DNA barcodes for species rich lineages.