Phylogenetic and morphological analysis of Antarctic lichen-forming Usnea species in the group Neuropogon

摘要: Usnea species of the Neuropogon group are amongst most widespread and abundant macrolichens in Antarctic regions. Four principal species, U. antarctica, aurantiaco-atra, sphacelata subantarctica, have been described on morphological grounds. However, identification to level is often difficult atypical morphologies frequently arise. Over 400 specimens were collected Peninsula Falkland Islands. Both molecular characters (ITS RPB1) used compare samples clarify taxonomic relationships. Morphological characteristics included presence apothecia, apothecial rays, soredia, papillae, fibrils, pigmentation diameter central axis as a proportion branch diameter. Results revealed very close relationship between antarctica suggesting that they might constitute pair or be conspecific. was comprised at least two genetically distinct groups with no clear differences morphology. One first reported fertile specimen this species. subantarctica phylogenetically from other main but clustered trachycarpa. Genetic variation evident within all although there correlation geographic origin genetic relatedness. Phylogenetic analyses indicated circumscription needs revision, being non-monophyletic. None characters, study proved completely unambiguous markers for single thickness supported informative monophyletic lineages group.