Arthothelium

Arthothelium
Arthothelium spectabile
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Arthoniomycetes
Order: Arthoniales
Family: Arthoniaceae
Genus: Arthothelium
A.Massal. (1852)
Type species
Arthothelium tremellosum
(Eschw.) A.Massal. (1852)
Synonyms[1]

Arthothelium is a genus of lichen-forming fungi in the family Arthoniaceae.[2]

Description

[edit]

Arthothelium is a genus of crustose lichens, which can either be immersed (embedded within the substrate) or superficial (growing on the surface). The thallus may spread freely or be confined to specific areas. The lichen's photobiont (the algae or cyanobacteria involved in its symbiosis) can vary, including types from the genus Trentpohlia, the family Chlorococcaceae, or may be absent altogether.[3]

The reproductive structures resemble apothecia, a common form of lichen fruiting body, and come in various shapes, from flat to convex, and may be elongated or star-like. These structures, known as the disc, range in colour from red-brown to black, and can sometimes have a frosted, powdery appearance (pruinose). A thalline margin, which in some lichens surrounds the fruiting body, is absent in Arthothelium. The exciple, a rim of tissue found in some lichen fruiting bodies, is also absent.[3]

The uppermost layer of the apothecium, the epithecium, can be colourless, red-brown, or dark brown. Below this, the hymenium, where the spores develop, often turns blue when tested with iodine (I+). The hypothecium, the supportive tissue beneath the hymenium, is variable in thickness and ranges from dark red-brown to dark brown in colour. The hymenium contains filaments called paraphysoids, which are sparsely to densely branched and often have swollen, red-brown tips.[3]

The asci (spore-producing cells) are usually clavate (club-shaped) or ellipsoidal, containing eight spores. They are semi-fissitunicate, meaning they have two wall layers that split during spore release, and feature a large apical dome with a distinct ocular chamber. The ascospores are obovoid to ellipsoidal, colourless, and muriform, meaning they are divided by multiple internal walls, creating a brick-like pattern. This is a key distinguishing feature from similar genera like Arthonia, where the spores are only divided by transverse walls.[3]

Conidiomata (structures producing asexual spores) resemble those found in Arthonia. The genus generally lacks lichen products (secondary metabolites), in species found in Britain and Ireland, but elsewhere, species may contain xanthones or anthraquinones.[3]

Arthothelium typically grows on smooth bark in humid, undisturbed habitats, although it is rarely found on rock. The genus includes around 50 species and has a cosmopolitan distribution, with most species occurring in tropical regions. It is considered polyphyletic, meaning the genus likely includes species that do not share a common evolutionary ancestor, and further study is needed on its type species, Arthothelium tremellosum.[3]

Species

[edit]

As of October 2024, Species Fungorum (in the Catalogue of Life) accept 26 species of Arthothelium:[4]

Arthonia interveniens
Photograph of an ascus from A. spectabile taken through a compound microscope (x1000), showing a ballon-shaped ascus containing eight, hyaline, muriform spores.

References

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  1. ^ "Synonymy. Current Name: Arthothelium A. Massal., Ric. auton. lich. crost. (Verona): 54 (1852)". Species Fungorum. Retrieved 9 November 2022.
  2. ^ Wijayawardene, N.N.; Hyde, K.D.; Dai, D.Q.; Sánchez-García, M.; Goto, B.T.; Saxena, R.K.; et al. (2022). "Outline of Fungi and fungus-like taxa – 2021". Mycosphere. 13 (1): 53–453. doi:10.5943/mycosphere/13/1/2. hdl:10481/76378.
  3. ^ a b c d e f Cannon, P.; Ertz, D.; Frisch, A.; Aptroot, A.; Chambers, S.; Coppins, B.; Sanderson, N.; Simkin, J.; Wolselsey, P. (2020). Arthoniales: Arthoniaceae, including the genera Arthonia, Arthothelium, Briancoppinsia, Bryostigma, Coniocarpon, Diarthonis, Inoderma, Naevia, Pachnolepia, Reichlingia, Snippocia, Sporodophoron, Synarthonia and Tylophoron. Revisions of British and Irish Lichens. Vol. 1. p. 27. doi:10.34885/173.
  4. ^ "Arthothelium". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 23 October 2024.
  5. ^ a b Müller, J. (1894). "Conspectus systematicus lichenum Novae Zelandiae" [Systematic synopsis of the lichens of New Zealand]. Bulletin de l'Herbier Boissier. 2 (App. 1): 1–114.
  6. ^ a b c d Van den Broeck, D.; Tehler, A.; Razafindrahaja, T.; Ertz, D. (2017). "Four new species of Arthothelium (Arthoniales, Ascomycetes) from Africa and Socotra". Phytotaxa. 331 (1): 51–64. doi:10.11646/phytotaxa.331.1.3.
  7. ^ a b c d Kantvilas, G. (2021). "A synopsis of the genus Arthothelium (Arthoniales) in Tasmania". The Lichenologist. 53 (6): 415–431. doi:10.1017/S0024282921000402.
  8. ^ a b c Zahlbruckner, A. (1922). Catalogus Lichenum Universalis [Universal Catalogue of Lichens] (in Latin). Vol. 2. pp. 163–642.
  9. ^ Aptroot, A.; Wirth, V. (2006). "A new saxicolous Arthothelium from the Namibia desert". The Lichenologist. 38 (2): 123–126. doi:10.1017/S0024282906005585.
  10. ^ Coppins, B.J. (1989). "Notes on the Arthoniaceae in the British Isles". The Lichenologist. 21 (3): 195–216. doi:10.1017/S0024282989000435.
  11. ^ Fryday, A.M. (2002). "New combinations and records of lichenized-fungi from southern South America". Mycotaxon. 82: 421–428.
  12. ^ Øvstedal, D.O.; Gremmen, N.J.M. (2001). "The lichens of Marion and Prince Edward Islands". South African Journal of Botany. 67 (4): 552–572. doi:10.1016/S0254-6299(15)31187-X.
  13. ^ Seaward, M.R.D.; Aptroot, A. (2004). "Four Seychelles lichens new to science". The Lichenologist. 36 (2): 119–124. doi:10.1017/S002428290401401X.
  14. ^ Ertz, D.; Fryday, A.M. (2017). "A remarkable endohymenial species of Arthothelium (Arthoniales) from Campbell Island, New Zealand". The Lichenologist. 49 (1): 93–97. doi:10.1017/S0024282916000554.
  15. ^ Etayo, J.; Aptroot, A. (2017). "New and interesting lichens from Panama". The Bryologist. 120 (4): 501–510. doi:10.1639/0007-2745-120.4.501.
  16. ^ Harada, H.; Okamoto, T.; Yoshimura, I. (2004). "A Checklist of Lichens and Lichen-allies of Japan". Lichenology. 2 (2): 47–166.
  17. ^ Coppins, B.J.; James, P.W. (1979). "New or interesting British lichens III". The Lichenologist. 11 (1): 27–45. doi:10.1017/S0024282979000049.
  18. ^ Ahti, T.; Brodo, I.M.; Noble, W.J. (1987). "Contributions to the lichen flora of British Columbia, Canada". Mycotaxon. 28 (1): 91.
  19. ^ a b Massalongo, A.B. (1852). Ricerche sull'autonomia dei licheni crostosi [Research on the autonomy of crustose lichens]. pp. 1–221.
  20. ^ a b Müller, J. (1895). "Sertum Australiense s. species novae Australienses Thelotremearum, Graphidearum et Pyrenocarpearum" [Australian collection of new Australian species of Thelotremeae, Graphideae and Pyrenocarpeae]. Bulletin de l'Herbier Boissier. 3: 313–327.
  21. ^ Coppins, B.J.; Tønsberg, T. (1984). "A new species of Arthothelium from Norway". Nordic Journal of Botany. 4 (1): 75–77. doi:10.1111/j.1756-1051.1984.tb01976.x.
  22. ^ Hasse, H.E. (1913). The lichen flora of southern California. Contributions from the United States National Herbarium. Vol. 17. pp. 1–132.
  23. ^ a b Müller, J. (1893). "Lichenes Wilsoniani, s. lichenes a cl. Rev. F.R.M.Wilson in Australiae prov. Victoria lecti" [Wilson's lichens, or lichens collected by Rev. F.R.M. Wilson in Victoria Province, Australia]. Bulletin de l'Herbier Boissier. 1: 33–65.
  24. ^ Park, J.S.; Park, S.Y.; Park, C.H.; Jang, S.H.; Hur, J.S. (2017). "Arthothelium punctatum (Arthoniaceae, Arthoniales), a new lichen species from South Korea". Mycobiology. 45 (4): 255–262. doi:10.5941/MYCO.2017.45.4.255.
  25. ^ Körber, G.W. (1861). Parerga lichenologica. Ergänzungen zum Systema lichenum Germaniae [Lichenological supplements. Additions to the system of German lichens] (in German). Vol. 3. pp. 193–288.
  26. ^ Fries, T.M. (1865). "Bidrag till Skandinaviens Laf-flora" [Contribution to Scandinavia's lichen flora]. Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar. 21: 269.
  27. ^ Kantvilas, G.; Vězda, A. (1992). "Additions to the lichen flora of Tasmania". Telopea. 4 (4): 661–670. doi:10.7751/telopea19814953.
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