Inaccessible Biodiversity on Limestone Cliffs: Aster tianmenshanensis (Asteraceae), a New Critically Endangered Species from China

Abstract

Aster tianmenshanensis G. J. Zhang & T. G. Gao, a new species of Asteraceae from southern China is described and illustrated based on evidence from morphology, micromorphology and molecular phylogeny. The new species is superficially similar to Aster salwinensis Onno in having rosettes of spatulate leaves and a solitary, terminal capitulum, but it differs by its glabrous leaf margins, unequal disc floret lobes and 1-seriate pappus. The molecular phylogenetic analysis, based on nuclear sequences ITS, ETS and chloroplast sequence trnL-F, showed that the new species was nested within the genus Aster and formed a well supported clade with Aster verticillatus (Reinw.) Brouillet et al. The new species differs from the latter in having unbranched stems, much larger capitula, unequal disc floret lobes, beakless achenes and persistent pappus. In particular, A. tianmenshanensis has very short stigmatic lines, only ca. 0.18 mm long and less than 1/3 of the length of sterile style tip appendages, remarkably different from its congeners. This type of stigmatic line, as far as we know, has not been found in any other species of Aster. The very short stigmatic lines plus the unequal disc floret lobes imply that the new species may have a very specialized pollination system, which may be a consequence of habitat specialization. The new species grows only on the limestone cliffs of Mt. Tianmen, Hunan Province, at the elevation of 1400 m. It could only be accessed when a plank walkway was built across the cliffs for tourists. As it is known only from an area estimated at less than 10 km2 and a walkway passes through this location, its habitat could be easily disturbed. This species should best be treated as Critically Endangered based on the International Union for Conservation of Nature Red List Categories and Criteria B2a.

Aster saxicola sp. nov. (Asteraceae, Astereae), a new species from Guizhou, China: evidence from morphological, molecular and cytological studies

“…nrDNA ITS, ETS and cpDNA trnL-F have become the most frequently used molecular markers for phylogenetic studies of the tribe Astereae (Markos and Baldwin 2001, Fiz et al 2002, Li et al 2012, Jafari et al 2015, Zhang et al 2015, Xiao et al 2019. Our phylogenetic results showed that two samples of the new taxon formed a monophyletic group (ML = 100, PP = 1.00 in Fig.…”

“…The sequences of the nrDNA ITS, ETS and plastid DNA trnL-F were used in phylogenetic analyses and their boundaries were determined according to Li et al (2012). Our combined data set contained a total 183 DNA sequences; most of these were downloaded from GenBank (Li et al 2012, 2017, Zhang et al 2015, Xiao et al 2019), but 13 accessions were newly sequenced for this study. The sequences were initially aligned using Clustal X ver.…”

Peer Review #1 of "Convergent origin of the narrowly lanceolate leaf in the genus Aster—with special reference to an unexpected discovery of a new Aster species from East China (v0.1)"

“…The ITS, ETS and trnL-F sequences were selected as molecular markers to generate the datasets. According to previous studies (Li et al, 2012;Zhang et al, 2015), the systematic position of shrub and alpine Aster groups are distinct from the core Aster (sensu Zhang et al, 2015; including the type of genus, Aster amellus) and may represent separate genera.…”

“…Five samples of the potential new taxon and six of the superficially similar Aster dolichophyllus were added in this study. The taxonomic treatment in the Flora of China and the definitions of Aster and "core Aster" in our previous study (Zhang et al, 2015) were followed. In the phylogenetic analysis, PeerJ reviewing PDF | (2018:08:30777:1:1:NEW 6 Dec 2018)…”

“…Manuscript to be reviewed Chrysanthemum indicum L. was designated as outgroup as in previous studies (Li et al, 2012;Zhang et al, 2015). The ITS, ETS and trnL-F sequences were selected as molecular markers to generate the datasets.…”