Publication Date:
2023-10-28
Description:
Usnea species of the Neuropogon group are amongst the most widespread and abundant macrolichens in Antarctic regions. Four principal species, U. antarctica, U. aurantiaco-atra, U. sphacelata and U. subantarctica, have been described on morphological grounds. However, identification to species level is often difficult and atypical morphologies frequently arise. Over 400 specimens were collected on the Antarctic Peninsula and Falkland Islands. Both morphological and molecular characters (ITS and RPB1) were used to compare samples to clarify taxonomic relationships. Morphological characteristics used included presence of apothecia, apothecial rays, soredia, papillae, fibrils, pigmentation and the diameter of the central axis as a proportion of branch diameter. Results revealed a very close relationship between U. antarctica and U. aurantiaco-atra, suggesting that they might constitute a species pair or be conspecific. Usnea sphacelata was comprised of at least two genetically distinct groups with no clear differences in morphology. One group included the first reported fertile specimen of this species. Usnea subantarctica was phylogenetically distinct from the other main Antarctic Usnea species, but clustered with U. trachycarpa. Genetic variation was evident within all species although there was no clear correlation between geographic origin and genetic relatedness. Phylogenetic analyses indicated that species circumscription in the Neuropogon group needs revision, with the principal species being non-monophyletic. None of the morphological characters, or groups of characters, used in this study proved to be completely unambiguous markers for a single species. However, axis thickness was supported as being informative for the identification of monophyletic lineages within the group.
Keywords:
Antarctica; Antarctic Peninsula; Area/locality; Biological sample; BIOS; Carlini_Base_C1; Carlini/Jubany Station; Chimborazo_Area; Ecuador; Event label; Falkland Islands, East Falkland, East of Stanley; Jubany; Jubany_Station_C1; Lapataia_Bay; Latitude of event; Livingston_Island_Station; Longitude of event; Mars_Oasis; MULT; Multiple investigations; Potter Cove, King George Island, Antarctic Peninsula; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; Research station; Rothera_St; RS; Sampling date; SPP1158; Stanley_Area; Svalbard; Tierra del Fuego, South America; Usnea acromelana; Usnea antarctica; Usnea aurantiacoatra; Usnea sphacelata; Usnea spp.; Usnea subantarctica; Usnea trachycarpa
Type:
Dataset
Format:
text/tab-separated-values, 72 data points
Permalink
