Protoblastenia westbergii Pykälä & Myllys, 2025

Pykälä, Juha & Myllys, Leena, 2025, Unexpected species richness of the lichen genus Protoblastenia (Lecanorales, Psoraceae) in Finland, MycoKeys 124, pp. 193-226 : 193-226

Protoblastenia westbergii Pykälä & Myllys sp. nov.

Fig. 5 D

Diagnosis.

Differs from P. dolomitica in having slightly broader spores, darker orange apothecia and a thicker hypothecium.

Type.

Finland • Enontekiön Lappi, Enontekiö, Kilpisjärvi, Saana Nature Reserve, E-part , fell, steep SW-slope, on dolomite boulder, 910 m a. s. l., 69°02'N, 20°51'E, 13 August 2011, J. Pykälä 44316 ( H 9229821 – holotype, GenBank accession number: PV 766718 ) .

Description.

Thallus white to whitish-grey, rimose to areolate, areoles 0.15–0.8 mm, ca. 0.05–0.3 mm thick, K-, C-, UV- to UV + bluish-white, algal cells 4–8 μm, thallus often strongly invaded by cyanobacteria. Apothecia orange to dark brownish-orange, 0.2–1.1 mm, slightly convex to convex, 3 / 4 - immersed to superficial, in one specimen with pale margin ca. 30–50 μm thick; ca. 40–200 apothecia / cm 2. Epihymenium dirty yellow to orange-brown, 10–15 μm thick, K + violet. Hymenium 40–70 μm thick, often with oil droplets. Hypothecium red-brown to red-violet, ca. 60–150 μm thick. Paraphyses ca. 2–2.5 μm thick, apex not thickened to slightly thickened to 3 μm thick, some branched and anastomosing. Ascospores 0 - septate, (8.4 –) 10.5–12.0 – 13.6 (– 15.0) × (5.0 –) 5.4–6.1 – 6.9 (– 7.8) μm (n = 39).

Habitat and distribution.

Four specimens are known from the calcareous Saana and Toskalharji fells in NW Finland. On Saana, both specimens occurred close to each other on a steep SW-slope on a dolomite boulder. On Toskalharji, the species was found on a SE-facing slope on dolomite pebbles. The species may prefer dry, sun-exposed habitats. Companion species include Farnoldia jurana , Parmeliella thriptophylla (Ach.) Müll. Arg. , Thelidium auruntii and Verrucaria sp.

Etymology.

The name is in honour of Dr Martin Westberg ( Uppsala) for his important work on the taxonomy and biogeography of northern European lichens.

Notes.

The species is closely related to P. dolomitica (4 % difference in ITS). Protoblastenia dolomitica has, on average, smaller and paler, sometimes olive-yellow apothecia, narrower spores and a thinner hypothecium. However, P. westbergii often also has a thin hypothecium. Protoblastenia arupii has slightly broader spores, a thin hypothecium and possibly thinner thallus.

Other specimens examined.

Finland • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , fell, dolomite scree, gentle SE-slope, on dolomite pebbles, 715 m a. s. l., 69°11'N, 21°26'E, 2. 8. 2011, J. Pykälä 43196 ( H) ; • Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , fell, dolomite rock outcrop, SE-slope, on dolomite pebbles, 720 m a. s. l., 69°12'N, 21°26'E, 2. 8. 2011, J. Pykälä 43279 ( H) ; • Enontekiö, Kilpisjärvi, Saana Nature Reserve, E-part , fell, steep SW-slope, on dolomite boulder, 910 m a. s. l., 69°02'N, 20°51'E, 13. 8. 2011, J. Pykälä 44314 ( H) .

Figures

Figure 5. A. Protoblastenia saanaensis (holotype); B. P. timdalii (holotype); C. P. violacea (holotype); D. P. westbergii (holotype). Scale bars: 0.5 mm.