Phylogeny and Taxonomy on Cryptic Species of Forked Ferns of Asia

Abstract

Cryptic species comprise two or more taxa that are grounded under a single name because they are more-or-less indistinguishable morphologically. These species are potentially important for detailed assessments of biodiversity, but there now appear to be many more cryptic species than previously estimated. One taxonomic group likely to contain many cryptic species is Dicranopteris, a genus of forked ferns that occurs commonly along roadsides in Asia. The genus has a complex taxonomical history, and D. linearis has been particularly challenging with many intra-specific taxa dubiously erected to accommodate morphological variation that lacks clear discontinuities. To resolve species boundaries within Dicranopteris, we applied a molecular phylogenetic approach as complementary to morphology. Specifically, we used five chloroplast gene regions (rbcL, atpB, rps4, matK, and trnL-trnF) to generate a well-resolved phylogeny based on 37 samples representing 13 taxa of Dicranopteris, spanning the major distributional area in Asia. The results showed that Dicranopteris consists of ten highly supported clades, and D. linearis is polyphyletic, suggesting cryptic diversity within the species. Further through morphological comparison, we certainly erected Dicranopteris austrosinensis Y.H. Yan & Z.Y. Wei sp. nov. and Dicranopteris baliensis Y.H. Yan & Z.Y. Wei sp. nov. as distinct species and proposed five new combinations. We also inferred that the extant diversity of the genus Dicranopteris may result from relatively recent diversification in the Miocene based on divergence time dating. Overall, our study not only provided additional insights on the Gleicheniaceae tree of life, but also served as a case of integrating molecular and morphological approaches to elucidate cryptic diversity in taxonomically difficult groups.

Chloroplast phylogenomics and the taxonomy of Saxifraga section Ciliatae (Saxifragaceae)

“…Among these PCGs, matK gene encodes the only mature enzyme related to chloroplast group II intron splicing in land plants. It is one of the most rapidly evolving genes and is widely used in phylogenetic reconstruction in angiosperms (Fan et al, 2022; Kim et al, 2019; Kuo et al, 2011; Wei et al, 2021). Ycf1 is a coding region containing long tandem repeats.…”

Prospecting for rare earth element (hyper)accumulators in the Paris Herbarium using X-ray fluorescence spectroscopy reveals new distributional and taxon discoveries

“…The XRF scanning results show that 147 specimens of B. orientalis and 56 specimens of D. linearis accumulate Y in their leaves up to concentrations of 1424 and 697 µg g −1 , respectively. The fern D. linearis is widely documented for its REE (hyper)accumulation capabilities in China, but is in fact polyphyletic, representing a species complex of cryptic species ( Wei et al , 2022 ; Vieira Lima et al , 2023 ). This study reveals that some specimens of D. linearis accumulating >1000 µg g −1 REEs in their fronds are from Indonesia and the Philippines, but these populations may well represent distinct species within the D. linearis complex.…”