Biology:Metamelanea
Metamelanea is a small genus of lichen-forming fungi in the family Lichinaceae.[1] It consists of three species of rock-dwelling lichens.[2]
Taxonomy
The genus was circumscribed by the German lichenologist Aino Henssen in 1989, with the newly described species M. umbonata assigned as the type, and a second included species, M. melambola.[3] A third species was added to the genus the following year.[4] The genus name alludes to the dark colouration of the thallus and fruiting bodies.[3]
Description
The thallus of Metamelanea appears blackish and has a cracked, [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] texture, meaning it is divided into small, island-like segments called [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]. The thallus is composed of densely packed rows of lichenised colonies containing a single-celled cyanobacterium (blue-green alga) as the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]. These colonies are surrounded by fungal hyphae. As the thallus grows, it tends to break up into vertical lobes. The photobiont belongs to the order Chroococcales and is characterised by a distinctive brown gelatinous sheath, which contributes to the lichen's dark appearance.[3]
The apothecia (fruiting bodies) of Metamelanea are darkly pigmented and can be either [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] in the thallus or sitting on its surface (adnate). The appearance of the apothecia varies between species. In M. umbonata, the apothecia protrude above the thallus surface and have a distinctive [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (having a rounded elevation in the centre) or [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (convoluted or wavy) shape. When moistened, the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of these apothecia appear strikingly black. In M. melambola, the apothecia remain immersed in the thallus and are difficult to observe when dry. Upon moistening, they become visible as flat, multidivided discs. These apothecia can grow quite large and may appear as clusters of smaller apothecia due to their divided nature.[3]
Unlike some other genera in the Lichinaceae, the apothecia in Metamelanea develop between the lobes rather than within them. This results in the absence of a true [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (a rim of thalline tissue surrounding the apothecium), despite earlier descriptions suggesting otherwise. Pycnidia, which are asexual reproductive structures, have been observed in M. umbonata. These are immersed in the thallus and contain oblong cells that produce small, rod-like conidia (asexual spores) at their tips.[3]
Species
- Metamelanea caesiella (Th.Fr.) Henssen (1990)
- Metamelanea melambola (Tuck.) Henssen (1989)
- Metamelanea umbonata Henssen (1989)
References
- ↑ "Metamelanea". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/62ZVK.
- ↑ 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 [180]. doi:10.5943/mycosphere/13/1/2. https://www.researchgate.net/publication/358798332.
- ↑ 3.0 3.1 3.2 3.3 3.4 Henssen, A. (1989). "Metamelanea and Stromatella, new genera of Lichinaceae". The Lichenologist 21 (2): 101–118. doi:10.1017/s002428298900023x.
- ↑ Henssen, Aino; Jørgensen, Per Magnus (1990). "New combinations and synonyms in the Lichinaceae". The Lichenologist 22 (2): 137–147. doi:10.1017/S0024282990000093.
Wikidata ☰ Q10582680 entry
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