Protoblastenia dolomitica 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 dolomitica Pykälä & Myllys sp. nov.

Fig. 2 D

Diagnosis.

Differs from P. siebenhaariana in having more densely occurring apothecia and from P. arupii in having a rimose to areolate thallus and often olive-yellow apothecia.

Type.

Finland • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , fell, brook, W-shore, dolomite rock outcrop, on N-slope, 710 m a. s. l., 69°11'N, 21°26'E, 3 August 2011, J. Pykälä 43466 ( H 9235018 – holotype, GenBank accession number: PV 766671 ) .

Description.

Thallus white to whitish-grey, rarely pale brown, rimose to areolate, areoles 0.2–0.9 mm, ca. 0.03–0.25 mm thick, K-, C-, UV-, one specimen UV + bluish-white, algal cells 4–8 (– 12) μm. Apothecia yellow to dirty orange-yellow, sometimes olive-yellow, 0.15–0.7 mm, plane, slightly convex to convex, 1 / 2 - immersed in thallus; ca. 40–160 apothecia / cm 2. Epihymenium dirty olive-yellow to orange-brown, 12–20 μm thick, K + violet. Hymenium 50–70 μm thick. Hypothecium dark brown, reddish-brown or usually violet, ca. 40–100 μm thick. Paraphyses ca. 1.5–2 μm thick, apex not thickened to slightly thickened, branching. Ascospores 0 - septate, (7.6 –) 11.0–12.8 – 14.7 (– 19.4) × (4.4 –) 4.8–5.4 – 5.9 (– 7.4) μm (n = 117).

Habitat and distribution.

This species has been found only in the parishes of Salla (in the biogeographical Province Ks) and Enontekiö (biogeographical Province EnL) in N Finland. It grows on dolomite rock outcrops, once collected from dolomite stones and pebbles. The species may prefer sun-exposed and half-shady sites on fells and in gorges. Companion species include, for example, Acarospora glaucocarpa , Hymenelia rhodopis (Sommerf.) Lutzoni , Opegrapha dolomitica (Arnold) Clauzade & Cl. Roux ex Torrente & Egea , Polyblastia spp. , Protoblastenia fennoarctica , Synalissa ramulosa (Bernh.) Körb. , Thelidium auruntii (A. Massal.) Kremp. and T. declivum Pykälä & Myllys.

Etymology.

The species grows on dolomite rocks.

Notes.

Protoblastenia dolomitica is closely related to P. westbergii , which has slightly larger apothecia, broader spores and sometimes a thicker hypothecium. The specimens have been previously identified as P. siebenhaariana in Finland. However, this species has only 1–10 apothecia / cm 2 ( Kainz and Rambold 2004) and the Finnish specimens are not closely related to a GenBank specimen of P. siebenhaariana . Protoblastenia dolomitica is characterised by rather small, often dirty olive-yellow apothecia and a thin hypothecium. Protoblastenia arupii , based on the inspection of only one known specimen, has orange apothecia, on average, broader spores and an only slightly thinner rimose thallus. More material from the morphologically related species is needed to determine whether P. dolomitica can be identified by morphology only.

Other specimens examined.

Finland • Koillismaa, Salla, Oulanka National Park, Pikkuköngäs, bank of River Oulankajoki , high cliff, calciferous (dolomite) schistose rock, on overhanging SW-facing wall, 180 m a. s. l., 66°25'N, 29°09'E, 10. 8. 2009, J. Pykälä 36072 ( H) ; • Salla, Oulanka National Park, Pikkuköngäs, bank of River Oulankajoki , high cliff, calciferous (dolomite) schistose rock outcrop, on SE-facing wall, 182 m a. s. l., 66°25'N, 29°08'E, 4. 8. 2010, J. Pykälä 39217 ( H) ; • Salla, Oulanka National Park, Pikkuköngäs, bank of River Oulankajoki , high cliff, calciferous (dolomite) schistose rock outcrop, beneath SW-facing wall, on pebble, 180 m a. s. l., 66°25'N, 29°08'E, 13. 8. 2010, J. Pykälä 39851 ( H) ; • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , fell, dolomite rock outcrop, gentle SE-slope, on dolomite pebbles, 730 m a. s. l., 69°12'N, 21°26'E, 2. 8. 2011, J. Pykälä 43340 ( H) ; • Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N , lake shore, dolomite scree, on dolomite stones, 705 m a. s. l., 69°11'N, 21°26'E, 7. 8. 2011, J. Pykälä 43855 ( 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 44115 ( H) .

Figures

Figure 2. A. Protoblastenia arupii (holotype); B. P. borealis (holotype); C. P. compressa (holotype); D. P. dolomitica (holotype). Scale bars: 0.5 mm.