Biology:Austroplaca
Austroplaca is a genus of lichen-forming fungi in the family Teloschistaceae.[1] It comprises 13 species. These lichens are found primarily in the coldest regions of the Southern Hemisphere, including Antarctica, sub-Antarctic islands, and the southern tips of South America. Most species grow on rocks in harsh, windswept environments.
Taxonomy
The genus was circumscribed in 2013 by Ulrik Søchting, Patrik Frödén, and Ulf Arup, with Austroplaca ambitiosa assigned as the type species. The generic name means "southern disc". Molecular and morphological evidence indicate that Austroplaca is monophyletic; that is, its species form a single evolutionary lineage. It appears most closely related to two other Southern Hemisphere genera, Gondwania and Cerothallia. Gondwania chiefly shows a southern circumpolar distribution, in contrast to the Antarctic–Subantarctic–Patagonian range typical of Austroplaca, but the three genera otherwise span similar morphological and anatomical variation. Cerothallia differs in having spores with a short internal cross-wall (septum) and a poorly developed, grey, crustose thallus. [2]
Across analyses, these taxa do not consistently form a single, well-supported clade, and they cannot be united without also absorbing Xanthopeltis, Caloplaca altoandina, and several undescribed species. The authors considered that option but judged it would erase useful information carried by current genus names: for example, that Cerothallia comprises species with short-septate spores and weakly developed thalli, whereas Xanthopeltis sensu stricto has an [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] thallus (attached at one central point), [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] apothecia (sunken fruiting bodies), and narrow, one-septate, S-shaped spores. They therefore preferred to retain at least four genera rather than collapse them into one.[2]
Description
Most species of Austroplaca form low, circular rosettes with somewhat lobed edges. A minority are [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]: minute, shrubby thalli with tiny upright bumps (papillae), as in A. erecta. Others are crustose with a radiating, lobed outline ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), or break into small, shield-like plates (peltate [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) that often grow on moss or plant debris, for example A. darbishirei. The upper surface (thallus [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) commonly shows pseudocyphellae—fine pores or cracks that appear as pale specks and promote gas exchange. Only a few species produce soredia, the powdery propagules used for vegetative reproduction; examples include A. darbishirei and the high-latitude, bipolar A. soropelta (occurring in both polar regions).[2]
The fruiting bodies are apothecia of the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] type: small [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] edged by a margin formed from both the lichen thallus and the inner apothecial wall. The ascospores are typically two-celled, separated by a medium to broad cross-wall (septum). Chemically, species fall into [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] A or A3, indicating a characteristic, genus-typical suite of secondary metabolites used in Teloschistaceae classification.[2]
Species
As of September 2025[update], Species Fungorum (in the Catalogue of Life) accept 11 species of Austroplaca.[1]
- Austroplaca ambitiosa (Darb.) Søchting, Frödén & Arup (2013)
- Austroplaca cirrochrooides (Vain.) Søchting, Frödén & Arup (2013)
- Austroplaca darbishirei (C.W.Dodge & G.E.Baker) Søchting, Frödén & Arup (2013)
- Austroplaca erecta (Arup & H.Mayrhofer) Søchting, Frödén & Arup (2013)
- Austroplaca frigida Søchting & Garrido-Ben. (2014)[3] – Antarctica
- Austroplaca hookeri (C.W.Dodge) Søchting, Frödén & Arup (2013)
- Austroplaca imperialis Søchting, Sancho & Arup (2023)[4]
- Austroplaca johnstonii (C.W.Dodge) Søchting, Frödén & Arup (2013)
- Austroplaca lucens (Nyl.) Søchting, Frödén & Arup (2013)
- Austroplaca millegrana (Müll.Arg.) Søchting, Frödén & Arup (2013)
- Austroplaca sibirica (H.Magn.) Søchting & Arup (2021)[5]
- Austroplaca soropelta (E.S.Hansen, Poelt & Søchting) Søchting, Frödén & Arup (2013)
- Austroplaca thisbe Søchting, Sancho & Arup (2023)[6] – Argentina
References
- ↑ 1.0 1.1 "Austroplaca". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/36G9.
- ↑ 2.0 2.1 2.2 2.3 Arup, Ulf; Søchting, Ulrik; Frödén, Patrik (2013). "A new taxonomy of the family Teloschistaceae". Nordic Journal of Botany 31 (1): 16–83. doi:10.1111/j.1756-1051.2013.00062.x. Bibcode: 2013NorJB..31...16A.
- ↑ Søchting, Ulrik; Garrido-Benavent, Isaac; Seppelt, Rod; Castello, Miris; Pérez-Ortega, Sergio; De Los Ríos Murillo, Asunción; Sancho, Leopoldo Garcia; Frödén, Patrik et al. (2014). "Charcotiana and Amundsenia, two new genera in Teloschistaceae (lichenized Ascomycota, subfamily Xanthorioideae) hosting two new species from continental Antarctica, and Austroplaca frigida, a new name for a continental Antarctic species". The Lichenologist 46 (6): 763–782. doi:10.1017/S0024282914000395. Bibcode: 2014ThLic..46..763S.
- ↑ Søchting, Ulrik; Sancho, Leo Garcia; Arup, Ulf (2023). "The lichen genera Gondwania and Transdrakea gen. nov. (Teloschistaceae) – speciation in three southern continents". Plant and Fungal Systematics 68 (2): 304–319. doi:10.35535/pfsyst-2023-0015.
- ↑ Søchting, U.; Arup, U. (2021). "Austroplaca sibirica (lichenized Ascomycota, Teloschistaceae) – a bipolar lichen with an austral origin documented by molecular data". Graphis Scripta 33 (1): 12–16.
- ↑ Søchting, Ulrik; Sancho, Leo G.; Arup, Ulf (2023). "Marchantiana pyramus, M. ramulicola and Austroplaca thisbe (Teloschistaceae, lichenized Ascomycota) – three new twig lichens from southern Patagonia". The Lichenologist 55 (5): 377–387. doi:10.1017/S0024282923000361. Bibcode: 2023ThLic..55..377S.
Wikidata ☰ Q25412675 entry
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