Masonhalea

Masonhalea is a genus of two species of lichenized fungi in the family Parmeliaceae.^[1]

Masonhalea
Masonhalea richardsonii
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Lecanorales
Family:	Parmeliaceae
Genus:	Masonhalea Kärnefelt (1977)
Type species
Masonhalea richardsonii (Hook.) Kärnefelt (1977)
Species
M. inermis M. richardsonii

Taxonomy

The genus was circumscribed by Swedish lichenologist Ingvar Kärnefelt in 1977, with Masonhalea richardsonii as the type, and at that time, only species. The genus name honours American lichenologist Mason Hale.^[2] The unusual morphology of this species – a vagrant lichen – attracted interest from several lichenologists, resulting in its placement in several genera, including Cornicularia, Evernia, Everniopsis, Platysma and Parmelia.^[3] Masonhalea inermis (formerly Cetraria crispa f. inermis) was added to the genus in 2011;^[4] a close genetic relationship between these two species was confirmed with molecular phylogenetics.^[3]

In 2017, Divakar and colleagues used a recently developed "temporal phylogenetic" approach to identify temporal bands for specific taxonomic ranks in the family Parmeliaceae, suggesting that groups of species that diverged within the time window of 29.45–32.55 million years ago represent genera. They proposed to synonymize Masonhalea with Nephromopsis, along with several other Parmelioid genera, so that all the genera within the Parmeliaceae are about the same age.^[5] Although some of their proposed taxonomic changes were accepted, the synonymization of the Parmelioid genera with Nephromopsis was not accepted in a recent analysis.^[6]

Description

Both Masonhalea species feature lateral apothecia, pycnidia on the thallus margin, a layer of cortical tissue beneath the wall of the pycnidia, and bacillariform (short cylindrical) conidia.^[3]

Species

• Masonhalea inermis (Nyl.) Lumbsch, Nelsen & A.Thell (2011)
• Masonhalea richardsonii (Hook.) Kärnefelt (1977)

References

1. Lücking, Robert; Hodkinson, Brendan P.; Leavitt, Steven D. (2017). "The 2016 classification of lichenized fungi in the Ascomycota and Basidiomycota–Approaching one thousand genera". The Bryologist. 119 (4): 361–416. doi:10.1639/0007-2745-119.4.361. S2CID 90258634.
2. Kärnefelt, Ingvar (1977). "Masonhalea, a new lichen genus in the Parmeliaceae". Botaniska Notiser. 130: 101–107.
3. Nelsen, Matthew P.; Thell, Arne; Leavitt, Steven D.; Hampton-Miller, Celia J.; Lumbsch, H. Thorsten (2013). "A reappraisal of Masonhalea (Parmeliaceae, Lecanorales) based on molecular and morphological data". The Lichenologist. 45 (6): 729–738. doi:10.1017/S0024282913000509. S2CID 84502429.
4. Thell, Arne; Moberg, Roland (2011). Nordic Lichen Flora. Vol. 4. Svenska Botaniska Föreningen. p. 67. ISBN 9789185221240.
5. Divakar, Pradeep K.; Crespo, Ana; Kraichak, Ekaphan; Leavitt, Steven D.; Singh, Garima; Schmitt, Imke; Lumbsch, H. Thorsten (2017). "Using a temporal phylogenetic method to harmonize family- and genus-level classification in the largest clade of lichen-forming fungi". Fungal Diversity. 84: 101–117. doi:10.1007/s13225-017-0379-z. S2CID 40674310.
6. Lücking, Robert (2019). "Stop the Abuse of Time! Strict Temporal Banding is not the Future of Rank-Based Classifications in Fungi (Including Lichens) and Other Organisms". Critical Reviews in Plant Sciences. 38 (3): 199–253. doi:10.1080/07352689.2019.1650517. S2CID 202859785.