An integrative approach to species delimitation sinks three Chinese limestone karst Elatostema (Urticaceae) species

By

Xin, Zibing
Monro, Alexandre
Wang, Ren-Fen
Fu, Long-Fei

Type

Article

Date of Publication

2023

Original Publication

PhytoKeys

Volume

236

Pages

83--96

Subjects

DNA barcoding , integrative taxonomy , phylogenetically informative morphological charact , Phylogeny , point-endemics

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers [2010]-

Identifiers

DOI: https://doi.org/10.3897/phytokeys.236.114837

 

Abstract

Elatostema is recognized as a taxonomically difficult group due to the reduced nature of the tiny flowers and inflorescences, also the large number of species (ca 650 to 700). Different opinions on morphological species delimitation have resulted in instability, which is problematic in such a speciose group. In this paper, the taxonomic status of three putative species, E. robustipes, E. scaposum, E. conduplicatum and their hypothetical closest relatives, was revised using morphological and molecular observations. Morphological comparison suggested high similarity between E. robustipes & E. retrohirtum, E. scaposum & E. oblongifolium, E. conduplicatum & E. coriaceifolium, respectively. Phylogenetic analyses of four universal DNA barcodes (ITS, trnH-psbA, matK and rbcL) suggested that each species pair represents a single evolutionary lineage. Taking these two findings together, we propose E. robustipes to be a synonym of E. retrohirtum, E. scaposum a synonym of E. oblongifolium, and E. conduplicatum a synonym of E. coriaceifolium. Our results recover the number, shape and size of the bracts and bracteoles to be relatively stable characters, and the disposition of the male inflorescences on modified stems to be an unstable character, unsuitable for species delimitation in Elatostema.