Thelidium toskalharjiense Pykaelae & Myllys, 2023

Pykaelae, Juha, Kantelinen, Annina & Myllys, Leena, 2023, Taxonomy of Thelidium auruntii and T. incavatum complexes (lichenized Ascomycota, Verrucariales) in Finland, MycoKeys 96, pp. 1-23 : 1

publication ID

https://dx.doi.org/10.3897/mycokeys.96.98738

persistent identifier

https://treatment.plazi.org/id/283BB1BF-30E6-583A-88D0-AAEB8BC08E65

treatment provided by

MycoKeys by Pensoft

scientific name

Thelidium toskalharjiense Pykaelae & Myllys
status

sp. nov.

Thelidium toskalharjiense Pykaelae & Myllys sp. nov.

Figs 2F View Figure 2 , 3A, C View Figure 3

Diagnosis.

Species morphologically rather similar to T. auruntii , but the spores are larger, and the involucrellum is, on average, shorter and thinner.

Type material.

Holotype. Finland, Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, fell, stony lake shore, on dolomite stones, 705 m a.s.l., 69°11'N, 21°26'E, 3 August 2011, J. Pykälä 43398 (H9206484, GenBank accession number: OP901882).

Description.

Prothallus not visible. Thallus grey to pale brownish grey, endolithic to thinly epilithic, rarely rimose, algal cells c. 5-8 μm, sometimes surrounded by dark lines. Perithecia 0.17-0.36 mm in diam., 1/2-3/4(-1)-immersed, leaving shallow to deep pits; c. 60-160 perithecia / cm2. Ostiole pale to dark, plane, c. 20-30(-60) μm wide. Involucrellum apical to covering half of the exciple, 20-50 μm thick, appressed to the exciple or strongly diverging from it. Exciple c. 0.15-0.24 mm, wall dark brown to black, c. 20-30 μm thick. Periphysoids c. 20-30 × 2-2.5 μm. Asci c. 73-83 × 23-29 μm, 8-spored. Ascospores 1-septate, (22.4-)26.8-29.1-31.3(-35.5) × (11.8-)12.5-13.4-14.2(-16.1) μm (n = 91).

Habitat and distribution.

The species occurs in the fell Toskalharji in northern Finland in Enontekiö within an area of three square kilometres and is divided into three subpopulations. It grows on dolomite boulders, stones and pebbles. Most specimens are from dolomite pebbles. It mostly grows on gentle slopes. The altitudinal range is 705-875 m a.s.l.

Etymology.

The species has been found only in the Toskalharji area.

Notes.

The species differs from T. auruntii by larger spores, but there is a considerable overlap in the spore size. The involucrellum is, on average, shorter and thinner, but few specimens of T. auruntii may have similar involucrellum to T. toskalharjiense . Nevertheless, based on ITS phylogeny, the species is not closely related to T. auruntii .

Other specimens examined.

Finland, Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji , Toskalpahta fell, SW-slope, scree, on dolomite pebbles, 790 m a.s.l, 69°11'N, 21°29'E, 1 August 2011, J. Pykälä 43090 (H); Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, fell, gentle SE-slope, on dolomite boulder, 715 m a.s.l, 69°11'N, 21°26'E, 2 August 2011, J. Pykälä 43211 (H); Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, fell, gentle SW-slope, dolomite rock outcrop, on dolomite pebbles, 715 m a.s.l, 69°11'N, 21°26'E, 3 August 2011, J. Pykälä 43364 (H); Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, close by lake shore, gentle NE-slope, alpine grassland on dolomite stone, 706 m a.s.l, 69°11'N, 21°26'E, 7 August 2011, J. Pykälä 43848 (H); Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, close by lake shore, alpine grassland, gentle SE-slope, dolomite rock outcrop, on dolomite pebbles, 706 m a.s.l, 69°11'N, 21°26'E, 7 August 2011, J. Pykälä 43861 (H) GoogleMaps .