Schaereria serenior

Schaereria serenior
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Schaereriales
Family:	Schaereriaceae
Genus:	Schaereria
Species:	S. serenior
Binomial name
Schaereria serenior (Vain.) Vitik. (2004)
Synonyms [1]
Lecidea tenebrosa var. sereniorVain. (1890) Lecidea serenior(Vain.) Hue (1913) Caloplaca serenior(Vain.) Zahlbr. (1931) Schaereria serenior(Vain.) Vitik., Ahti, Kuusinen, Lommi & T.Ulvinen (1997)

Schaereria serenior is a little-known species of saxicolous (bark-dwelling), crustose lichen in the family Schaereriaceae. ^[2] It is found in Finland. It has been listed as data deficient in the Finnish Regional Red List since 2000. ^[3] It also occurs in Lycksele, Sweden. ^[4]

Taxonomy

The lichen was first formally described as a new species by the Finnish lichenologist Edvard August Vainio, who classified it as a variety of the species Lecidea tenebrosa . In his original description published in 1883, Vainio named it Lecidea tenebrosa var. serenior and noted its distinctive features, including a thallus that turns slightly violet with iodine, initially innate apothecia (fruiting bodies) that become elevated, brownish-black colouration, and a "beautifully" blue-violet epithecium . He documented its habitat on granitic rock in Lake Inari in the pine forest region of Lapland. Vainio also provided several measurements to document microscopic characteristics of the lichen. ^[5]

Auguste-Marie Hue promoted the taxon to distinct species status in 1913 as Lecidea serenior. ^[6] Alexander Zahlbruckner proposed to transfer it to the genus Caloplaca in 1931. ^[7] Most recently, Orvo Vitikainen transferred it to Schaereria in 2004, ^[8] a few years after that genus had been resurrected from a long period of disuse. ^[9] It is one of two species of Schaereria found in Finland; the other is S. parasemella . ^[10]

Description

Schaereria serenior is a crustose lichen with several typical physical characteristics. The thallus (the main body of the lichen) is moderately thick to relatively thick, with a warty or warty- areolate surface texture. These warts are typically 0.4–0.5 mm wide (though they can range from 0.2–0.7 mm), and appear either well-defined or somewhat flattened and convex. The warts have a smooth surface, appearing ash-colored, and are scattered over a black hypothallus (the underlying layer). These warts tend to be either dispersed or somewhat contiguous, and notably lack soredia (powdery reproductive structures). ^[11]

The apothecia (reproductive structures) are initially embedded within the thallus warts for some time, eventually emerging with lecideine characteristics. They measure 0.5–1 mm in width, with a flat, black, naked, opaque disc . The apothecia have a permanent, black, naked, thin margin that often protrudes slightly and remains intact. ^[11]

Internally, the lichen has a colourless to pale hypothecium (the tissue beneath the spore-producing layer) with erect hyphae. The epithecium (the upper layer of the spore-producing structure) is violet-brown to sooty coloured. The paraphyses (sterile filaments between spore-producing cells) are loosely connected. The asci (spore-producing cells) are cylindrical to cylindrical-club shaped. Each ascus produces eight ascospores arranged in two rows. The spores are ellipsoid to somewhat spherical, measuring 7–12 μm in length and 5–8 μm in thickness. ^[11]

References

1. "GSD Species Synonymy. Current Name: Schaereria serenior (Vain.) Vitik., in Santesson, Moberg, Nordin, Tønsberg & Vitikainen, Lichen-Forming and Lichenicolous Fungi of Fennoscandia: 304 (2004)". Species Fungorum . Retrieved 7 January 2024.
2. "Schaereria serenior (Vain.) Vitik". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 7 January 2024.
3. "Schaereria serenior". Suomen Lajitietokeskus (in Finnish). Finnish Biodiversity Info Facility. 1 January 1980. Retrieved 2 April 2025.
4. Westberg, Martin; Moberg, R.; Myrdal, M.; Nordin, A.; Ekman, S. (2021). Santesson's Checklist of Fennoscandian Lichen-Forming and Lichenicolous Fungi. Uppsala: Evolutionsmuseet. p. 523. ISBN   978-91-519-9881-7.
5. Vainio, E.A. (1883). "Adjumenta ad lichenographiam Lapponiae Fennicae atque Fenniae borealis. II". Meddelanden af Societas pro Fauna et Flora Fennica (in Latin). 10: 89–88.
6. Hue, A. (1913). "Lichenes morphologice et anatomice disposuit". Nouvelles Archives du Museum d'Histoire Naturelle (in French). 3: 133–198.
7. Zahlbruckner, A. (1931). Catalogus Lichenum Universalis (in Latin). Vol. 7. Leipzig: Verlag von Gebrüder Borntraeger. p. 182.
8. Santesson, R.; Moberg, R.; Nordin, A.; Tønsberg, T.; Vitikainen, O. (2004). Lichen-forming and lichenicolous fungi of Fennoscandia. Svenska Botaniska Föreningen. Museum of Evolution, Uppsala University. p. 304. ISBN   91-972863-6-2.
9. Poelt, Josef; Vězda, Antonín (1977). Bestimmungsschlüssel europäischer Flechten. Ergänzungsheft 1. Bibliotheca Lichenologica (in German). Vol. 9. J. Cramer. pp. 1–258. ISBN   978-3-7682-1162-8.
10. Pykälä, Juha; Lommi, Sampsa (2021). "Lichen flora of Finland – short history of Finnish lichenology and updated species statistics". Memoranda Soc. Fauna Flora Fennica. 97: 73–88.
11. Vainio, Edvard August (1934). "Lichenographia Fennica IV. Lecideales 2" (PDF). Acta Societatis Pro Fauna et Flora Fennica (in Latin). 57 (2): 249–250.