Protoblastenia fennoarctica 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 fennoarctica Pykälä & Myllys sp. nov.

Fig. 3 B

Diagnosis.

Differs from P. calvella in having thinner hymenium, from P. minuta in having rimose to areolate thallus and from P. rikkinenii in usually having more densely occurring apothecia.

Type.

Finland • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, 1.2 km NE of Toskaljärvi , fell, SW-slope, scree, on dolomite boulder, 875 m a. s. l., 69°12'N, 21°28'E, 5 August 2011, J. Pykälä 43656 ( H 9220129 – holotype, GenBank accession number: PV 766677 ) .

Description.

Thallus white to pale greyish-brown, rimose to areolate, areoles 0.15–1.0 mm, ca. 0.03–0.25 mm thick, K-, C-, UV-, algal cells 5–10 μm. Apothecia yellow, orange-yellow to orange, 0.3–0.9 mm, plane to strongly convex, immersed in thallus to superficial; ca. 20–110 apothecia / cm 2. Epihymenium orange-yellow to brown, 12–20 μm thick, K + violet. Hymenium 50–80 μm thick. Hypothecium colourless to yellow, base sometimes patchily reddish-brown, ca. 60–280 μm thick. Paraphyses ca. 2–3 μm thick, cells 5–8 μm long, apex not thickened to slightly thickened, sparingly branched and anastomosing. Ascospores 0 - septate, (6.6 –) 8.7–10.0 – 11.3 (– 12.5) × (4.2 –) 4.8–5.3 – 5.9 (– 7.2) μm (n = 93).

Habitat and distribution.

This species has been found only in the Parish Enontekiö (biogeographical Province EnL in NW Finland). It grows on fells on dolomite rock outcrops, boulders and pebbles. Companion species include Enchylium polycarpon , Farnoldia jurana , Physcia caesia (Hoffm.) Fürnr. , Polyblastia spp. , Protoblastenia dolomitica and Verrucaria vacillans Pykälä & Myllys.

Etymology.

The species occurs in the most northern, almost arctic (oroarctic) sites in Finland (Fennia).

Notes.

Protoblastenia fennoarctica morphologically resembles P. calvella , P. minuta , P. remota and P. rikkinenii in having a pale hypothecium and small spores. In the ITS phylogeny, the species is most closely related to P. rikkinenii (Fig. 1 ). Protoblastenia rikkinenii differs in having more sparsely occurring apothecia, but more material is needed to confirm whether the two species can be identified by morphology. Protoblastenia calvella has a thicker hymenium (80–100 μm thick). Protoblastenia minuta and P. remota have an endolithic to thin thallus and P. minuta has smaller spores compared to P. fennoarctica , while P. remota may have slightly larger spores.

Other specimens examined.

Finland • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskalpahta fell, SW-slope, scree, on dolomite pebbles, 795 m a. s. l., 69°11'N, 21°29'E, 1. 8. 2011, J. Pykälä 43105 ( H) ; • Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , fell, dolomite scree, gentle SE-slope, on dolomite boulder, 715 m a. s. l., 69°11'N, 21°26'E, 2. 8. 2011, J. Pykälä 43194 ( H) ; • Enontekiö, Kilpisjärvi, Saana , fell, steep NE-slope, dolomite rock outcrop, on NE-facing wall, 820 m a. s. l., 69°02'N, 20°51'E, 11. 8. 2011, J. Pykälä 44116 ( H) .

Figures

Figure 1. Phylogenetic relationships of the studied Protoblastenia species, based on a Maximum Likelihood (ML) analysis of the ITS dataset. Maximum likelihood bootstrap values > 50 % are shown at nodes. Thickened lines indicate bootstrap values > 70 %. New species described in this study are indicated with shadowed boxes. GenBank accession numbers for sequences downloaded from GenBank and collection numbers for the specimens sequenced for this study are shown after the taxon names. Holotype specimens of the new species are shown in bold.

Figure 3. A. Protoblastenia ekmanii (holotype); B. P. fennoarctica (holotype); C. P. minuta (holotype); D. P. oulankaensis (holotype). Scale bars: 0.5 mm.