Protoblastenia remota Pykälä & Myllys sp. nov.

Fig. 4 C

Diagnosis.

Differs from P. borealis and P. pseudocompressa by often smaller more convex apothecia and a smaller thallus.

Type.

Finland • Varsinais-Suomi, Perniö, Lupaja, Alhonmäki, abandoned lime quarry, on W-slope, 9 August 1991, J. Pykälä 8547 (H 9250943 – holotype, GenBank accession number: PV 766698) .

Description.

Thallus white to grey, endolithic to sparse small areoles, 0.2–0.5 mm wide, ca. 0–0.15 mm thick, K-, C-, UV- to UV + bluish-white. Apothecia orange, 0.2–0.6 mm, convex to strongly convex, 1 / 2 - immersed to mainly superficial; ca. 15–80 apothecia / cm 2. Epihymenium yellow-brown to dark orange, 12–20 μm thick, K + violet. Hymenium 50–80 μm thick. Hypothecium colourless to pale yellow, ca. 100–200 μm thick. Paraphyses ca. 2–2.5 μm thick, apex not thickened to thickened to ca. 3–5 μm thick. Ascospores 0 - septate, (8.4 –) 9.8–11.4 – 12.9 (– 14.4) × (4.8 –) 5.0–5.6 – 6.1 (– 7.1) μm (n = 36).

Habitat and distribution.

Two specimens of this species are known: one from a lime quarry in SW Fnland and one from a calciferous schistose cliff in NE Finland. Companion species include Lathagrium fuscovirens, Mycobilimbia tetramera (De Not.) Vitik., Ahti, Kuusinen, Lommi & T. Ulvinen ex Hafellner & Türk and Verrucaria deversa . Furthermore, two closely-related specimens from North America and previously identified as Protoblastenia aff. rupestris (MZ 922194, MZ 922195) (Munger et al. 2022) may belong to P. remota (Fig. 1).

Etymology.

The name refers to the large difference in ITS of the species compared to other Protoblastenia species (differs by ca. 15–18 % from other species).

Notes.

Based on ITS sequences, this species is not closely related to any sequenced Protoblastenia species. The species is morphologically a typical Protoblastenia and very difficult to distinguish from several species, particularly from P. borealis and P. pseudocompressa . However, these two species have, on average, less convex apothecia, a thinner hypothecium and often a better developed thallus, but there is a wide overlap. In addition, Protoblastenia borealis often has larger apothecia (up to 1 mm).

Other specimens examined.

Finland • Koillismaa, Kuusamo, Oulanka National Park, Päähkänänkallio, high cliff, calciferous (dolomite) schistose rock outcrop, on SE-facing wall, st pc, 195 m a. s. l., 66°16'N, 29°31'E, 7. 8. 2010, J. Pykälä 39455 (H) .