Thamnolecania yunusii (Ramalinaceae) – A new species of lichenised fungus from Horseshoe Island (Antarctic Peninsula)

The new terricolous lichen species Thamnolecania yunusii Halıcı, Güllü, Bölükbaşı & Kahraman, which is characterised by its cream to greyish brown granulose-crustose thallus without vegetative propagules, is described from Horseshoe Island in the South-West Antarctic Peninsula region. All Thamnolecania species are known only from the Antarctic. The only species of the genus with a crustose thallus is T. racovitzae, but it differs from T. yunusii by growing on rocks, having an effuse to subeffigurate thallus that is sometimes isidiate and with shorter and narrower ascospores (c. 15 × 3.5 µm vs. 15.5–19.5 × 3.5–5.5 µm). The nrITS, mtSSU and RPB1 gene regions of the new species were studied and the phylogenetic position of the species was shown to be in the same clade as Thamnolecania gerlachei, T. brialmontii and T. racovitzae, but occurs on a different branch from these species. As T. yunusii is an Antarctic endemic, like the other Thamnolecania species, and most of the morphological characters fit well with this genus, we describe this new species under the genus Thamnolecania.