Lecanora immersocalcarea Aptroot, M.F. Souza & Spielmann, sp. nov.
Index Fungorum number: IF 900069; MycoBank number: MB 900069; Facesoffungi: FoF 13390; Fig. 1
Saxicolous Lecanora on limestone with thallus 0.5–0.8(- 2.0) mm thick, very pale ochraceous white, apothecia immersed in the thallus, black, immature.
Etymology – Named for the immersed apothecia and the calcareous habitat.
Holotype – Aptroot 77822.
Thallus crustose, superficial, covering areas up to 10 cm diam., dull, cretaceous, very pale ochraceous white, regularly cracked with the areoles angular, slightly convex and c. 0.5–0.9 mm diam., c. 0.5–0.8 mm thick but in some places with lobate superficial outgrowths of up to 2 mm thick, not surrounded by a prothallus, but margin thick and raised, sharply delimited, not lobed or fissured. Isidia and soredia absent. Ascomata immature apothecia, several per areole, flush with the thallus, rounded, 0.2–0.4 mm
diam.; disc black, margin thin, black. Epihymenium grey, without crystals. Excipulum without crystals. Hypothecium hyaline. Mature ascospores not observed. Pycnidia not observed.
Chemistry – Thallus UV–, C–, P+yellow, K +yellow. TLC: atranorin.
Distribution – On exposed limestone outcrop in Atlantic rain forest biome; only known from Brazil.
Material examined – Brazil. Mato Grosso do Sul: Serra da Bodoquena, Bodoquena, Dente de Cão, summit, alt. 450 m, 20° 47ʹ 05″ S, 56° 45ʹ 03″ W, on exposed limestone in an Atlantic rain forest biome, 7 November 2018, Aptroot 77822 (holotype, CGMC).
GenBank number – MW322682 (ITS)
Notes – This species is locally abundant. Fully fertile material was not found, but the type specimen was sequenced and clustered inside Lecanora Ach. in the current sense. Morphologically it would belong to the Lecanora marginata (Schaer.) Hertel & Rambold group, in which indeed calciferous species or at least specimens are known. Only one described species seems close, however, viz. Lecanora oreinodes (Körb.) Hertel & Rambold (Rambold 1989), which differs by the flatter, flush areoles and the somewhat fractured/lobate thallus margin, and which is not known to occur on pure limestone. Phylogenetically, it clusters deep inside Lecanora, where it clusters with several species with usnic acid instead of atranorin, but with low support (Fig. 2). Sequences of other species of the L. marginata group are not available. This species is described from the same locality as Buellia pruinocalcarea (for details see under Buellia pruinocalcarea).
Figure 1 – Lecanora immersocalcarea (Aptroot 77822, holotype). Habitat. Scale bar=23 mm
Figure 2 – Phylogram generated from maximum likelihood analysis based on ITS. Bootstrap support values for ML≥80% and Bayesian posterior probabilities≥0.95 are given near nodes respectively. The tree is rooted in Tephromela atra (L1489). Ex-type strains are in bold. The newly generated sequences are indicated in bold blue