MycoKeys 96: 1-23 (2023) er-reviewed open-access journal

doi: 10.3897/mycokeys.96.98738 < Mycokeys

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Taxonomy of Thelidium auruntii and T. incavatum complexes (lichenized Ascomycota, Verrucariales) in Finland

Juha Pykala', Annina Kantelinen?, Leena Myllys?

| Nature solutions, Finnish Environment Institute, Latokartanonkaari 11, 00790, Helsinki, Finland 2 Bota- ny Unit, Finnish Museum of Natural History, RO. Box 7, FI-00014, University of Helsinki, Helsinki, Finland

Corresponding author: Juha Pykala (juha.pykala@syke.fi)

Academic editor: T. Lumbsch | Received 12 December 2022 | Accepted 26 January 2023 | Published 8 March 2023

Citation: Pykala J, Kantelinen A, Myllys L (2023) Taxonomy of Thelidium auruntii and T: incavatum complexes (lichenized Ascomycota, Verrucariales) in Finland. MycoKeys 96: 1-23. https://doi.org/10.3897/mycokeys.96.98738

Abstract

The taxonomy of lichen species morphologically similar to Thelidium auruntii and T. incavatum in Fin- land is being revised. Based on ITS and morphology, ten species occur in Finland. All species are re- stricted to calcareous rocks. The Thelidium auruntii morphocomplex includes six species: T’ auruntii, T. huuskonenii sp. nov., T’ pseudoauruntii sp. nov., T: sallaense sp. nov, T: toskalharjiense sp. nov. and T. sp. 1. In the ITS phylogeny, 7’ auruntii, T! pseudoauruntii and T. sallaense group together, but the remaining species are placed outside of this clade. All the species have northern distribution in Finland, occurring on fells in NW Finland and/or in gorges in the Oulanka area in NE Finland. The Thelidium in- cavatum morphocomplex includes four species: 7’ declivum sp. nov., T. incavatum, T: mendax sp. nov. and I. sp. 2. This morphogroup is not resolved as monophyletic in the ITS phylogeny, with only 7° declivum and 7’ mendax forming a strongly supported group. Thelidium incavatum is rather common in SW Fin- land, with one separate locality in eastern Finland. Thelidium declivum occurs only in the Oulanka area. Thelidium mendax occurs in the Oulanka area, but one locality is known from eastern central Finland. Thelidium sp. 2 is known from one locality in SW Lapland.

Keywords Calcareous rocks, DNA barcoding, ITS, lichenized fungi, new species, phylogeny

Copyright Juha Pykald et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

2 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Introduction

Recently, many new species of Verrucaria, Polyblastia and related genera have been described from calcareous rocks of Europe (Savic and Tibell 2008, 2012; Breuss and Berger 2012; Orange 2014, 2020; Tibell and Tibell 2015; Pykala and Myllys 2016; Pykala et al. 2017a, b, 2018, 2019, 2020). However, during that time, only one new species of Thelidium has been described from Europe (Ceynowa-Gieldon 2007). Thiis and Nascimbene (2008) revised the taxonomy of the Central European freshwater spe- cies of Thelidium. No recent study exists on the taxonomy of any species complexes of Thelidium on calcareous rocks.

Thelidium A. Massal. is a polyphyletic genus widely dispersed within the Verrucari- aceae (Gueidan et al. 2007, 2009). The core of the species belongs to the so-called The- lium group, which also includes several species included in Polyblastia and Verrucaria.

In a previous study, we investigated the taxonomy of species of Verrucaria belong- ing to the Thelidium group and producing perithecia that leave pits on rocks in Finland (Pykala et al. 2020). Here, we continue the study on the taxonomy of the Thelidium group, focussing on the species morphologically similar to Thelidium auruntii (A. Mas- sal.) Kremp. and 7° incavatum Nyl. & Mudd. They are referred to here as 77 auruntii and 7. incavatum morphocomplexes. The Thelidium auruntii complex is characterised by 1-septate spores, an involucrellum (predominantly short), pale, thin or endolithic thallus and medium-sized perithecia. The Thelidium incavatum complex is character- ised by 3-septate spores, perithecia leaving pits, medium-sized exciple (0.2—-0.4 mm) and usually an endolithic pale thallus. Species belonging to the two complexes have similar habitat requirements and are restricted to calcareous rocks. Another species on calcareous rocks with 3-septate spores and perithecia leaving pits, 7’ fontigenum A. Massal., differs in its usually partly K+ violet thallus, smaller exciple (0.15—0.25 mm) and thin involucrellum.

Methods

This study is based on the material collected by the first author during the lichen inven- tory of calcareous rocks and lime quarries in Finland in 2003-2011, supplemented by one specimen collected in 2018. The sampling was most extensive in southern Finland (over 50% of all calcareous rocks and lime quarries studied) (Pykala et al. 2017a, b). The type material of putatively morphologically similar 7helidium species from her-

baria B, H, H-NYL, M, PRM, S, UPS, VER were studied for comparison.

Morphology

Perithecia and thalli were handsectioned with razor blades. The sections were ex- amined and measured in tap water. Asci and ascospores were also studied in squash

Taxonomy of Thelidium auruntii and T. incavatum complexes 3

preparations of perithecia mounted in water. Sections and squash preparations of old herbarium specimens were studied using potassium hydroxide (KOH). Additionally, involucrellum characters and exciple colour and diameter were examined by cutting perithecia into two pieces and studying the pieces using a binocular microscope.

The range of spore size is indicated as arithmetic mean and standard deviation. Minimum and maximum values are given in parentheses. ‘The size of the perithecia (in diameter) is given in surface view. The colour of the wall of the exciple was assessed from the basal parts.

DNA extraction and sequencing

Total genomic DNA was extracted from perithecia (1-3) of two- to ten-year-old her- barium specimens. The samples were placed in 96-well microplates and sent to the Canadian Centre for DNA Barcoding (CCDB). CCDB’s standard protocols (docu- mentation available at https://ccdb.ca/resources) were used for extraction, PCR and se- quencing. Primers ITS1 and ITS4 (White et al. 1990) were used both for PCR and se- quencing of the nuclear ribosomal ITS regions. The barcode sequences, their trace files along with all relevant collection data and photographs of the voucher specimens were uploaded to the Barcode of Life Data Systems (BOLD, https://www.boldsystems.org)

database. The sequences are available in GenBank (see Table 1 for accession numbers).

Phylogenetic analyses

We searched for the closest relatives of the new Thelidium species by using the BLAST search facility in Genbank (https://blast.ncbi.nlm.nih.gov/Blast.cgi). Based on BLAST, all species belong to the Thelidium group, but most of them do not have close relatives in GenBank. We used the following criteria for including GenBank sequences in our phylogeny: two sequences per species were selected if they have more than 95% simi- larity to any of our study species. Additionally, one sequence per species bearing more than 90% similarity to any study species was selected if they were among the 100 most similar sequences according to BLAST.

Based on this search, six ITS sequences of Polyblastia, six sequences of Thelidium and 17 sequences of Verrucaria in GenBank were selected to reconstruct a putative phy- logeny of the species (Table 1). Polyblastia albida Arnold and P fuscoargillacea Anzi were used as outgroups based on the studies of Gueidan et al. (2009) and Pykala et al. (2020).

A total of 76 ITS sequences were aligned with MUSCLE v.3.8.31 (Edgar 2004) us- ing EMBL-EBI’s web service (https://www.ebi.ac.uk/Tools/msa/muscle/). The aligned data set was subjected to maximum likelihood analysis (ML). The analysis was per- formed with RAxML v.8.1.3 (Stamatakis 2014) located at CSC — IT Center for Sci- ence (https://www.csc.fi/english). The ITS region was partitioned into ITS1, 5.8S and ITS2. The GTRGAMMA model was used for all partitions. Node support was esti- mated with 1000 bootstrap replications using the rapid bootstrap algorithm.

4 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Table |. Specimens used in the phylogenetic analyses. New sequences are in bold.

Species Country Voucher GenBank accession numbers Polyblastia abscondita Sweden Tibell 23641 (UPS) EU553507 P albida Sweden Savic 3021 (UPS) EU553492 P clandestina Sweden Nordin 5466 (UPS) EU559740 P lutosa Sweden Savic 3163 (UPS) EU559734 P moravica Sweden Savic 3154 (UPS) EW553522 P fuscoargillacea Sweden Palice 7666 (hb. Palice) EU553498 P. sp. Sweden Tibell 23635 (UPS) EU553503

Sweden Savic 3164 (UPS) EU553519 Thelidium auruntii Finland Pykala 36339 (H) OP901843 Finland Pykala 43414 (H) OP901844 Finland Pykala 43446 (H OP901845 Finland Pykala 43470 (H) OP901846 Finland Pykala 43829 (H) OP901847 Finland Pykala 43905 (H) OP901848 Finland Pykala 45171 (H) OP901849 T. declivum Finland Pykala 35996 (H) OP901850 Finland Pykala 36334 (H) OP901851 Finland Pykala 39640 (H) OP901852 Finland Pykala 39780b (H) OP901853 Finland Pykala 39997 (H) OP901854 Finland Pykaiki 40037 (H) OP901855 Finland Pykala 40047 (H) OP901856 Finland Pykala 44554 (H) OP901857 Finland Pykala 45123 (H) OP901858 T. huuskonenii Finland Pykala 31576 (H) OP901859 Finland Pykala 43243 (H) OP901860 Finland Pykala 43246 (H) OP901861 Finland Pykala 44167 (H) OP901862 T. incavatum Finland Pykala 34722 (H) OP901863 Finland Pykala 35282 (H) OP901864 Finland Pykala 36857 (H) OP901865 Finland Pykala 36867 (H) OP901866 Finland Pykala 37971 (H) OP901867 Finland Pykala 38227 (H) OP901868 Finland Pykala 38399 (H) OP901869 Finland Pykala 42871 (H) OP901870 Finland Pykala 46459 (H) OP901871 T. mendax Finland Pykala 39179 (H) OP901872 Finland Pykala 40152 (H) OP901873 Finland Pykala 42502 (H) OP901874 Finland Pykala 42503 (H) OP901875 T. methorium Austria Orange 21167 (NMW) MT 127220 UK Orange 16554 (NMW) FJ645267 T. papulare UK Orange 16531 (NMW) MT127197 T. pertusatii Italy Nascimbene JN1990 EU249471 T. pseudoauruntii Finland Pykala 45371 (H) OP901876 Finland Pykala 45374 (H) OP901877 T. pyrenophorum Sweden Tibell 23649 (UPS) EU553500 T: sallaense Finland Pykala 44902 (H) OP901878

Taxonomy of Thelidium auruntii and T. incavatum complexes 5

Species Country Voucher GenBank accession numbers T. toskalharjiense Finland Pykala 43090 (H) OP901879 Finland Pykala 43211 (H) OP901880 Finland Pykala 43364 (H) OP901881 Finland Pykala 43398 (H) OP901882 Finland Pykala 43848 (H) OP901883 Finland Pykala 43861 (H) OP901884 T. umbilicatum Sweden Tibell 23525 (UPS) EUS59/37, T. sp. 1 Finland Pykala 43208 (H) OP901885 T. sp. 2 Finland Pykala 52038 (H) OP901886 Verrucaria aethiobola Norway Orange 18946 (NMW) MT127203 V, anziana Norway Orange 17221 (NMW) FJ664835 V. bifurcata Finland Pykala 36722 (H) MT229720 °'V, calkinsiana” Canada McMullin (OAC) KT695332 V. cavernarum Finland Pykala 37975 (H) MT229724 V. devergens Finland Pykala 45367 (H) MT229741 °'V, deversa” Sweden Savic 3063 (UPS) EU553496 V. difficilis Finland Pykala 39060 (H) MT229743 V, karelica Finland Pykala 40325 (H) M1229762 V. kuusamoensis Finland Pykala 44694 (H) M1T229774 V. latebrosa UK Orange 16309 (NMW) FJ664864 V. pallidomurina UK Orange 22835 (NMW) MT127221 V. subdevergens Finland Pykala 44550 (H) MT229782 V. subtilis Finland Pykala 37329 (H) MT229810 V. tephromela UK Orange 19135 (NMW) MT127212 V. vacillans Finland Pykala 43272 (H) M1T229831 V. sp. Norway Orange 18952 (NMW) MT127205 Results

We generated 44 new ITS sequences for this study (Table 1). The alignment con- sisted of 526 sites of which sites 1-193 belonged to the ITS1 rDNA regions, sites 194-345 to the 5,8S rDNA gene and sites 346-526 to the ITS2 rDNA regions. The alignment is available in the Suppl. material 1. In the ITS phylogeny, eight new lineages are observed (Fig. 1). The lineages, when represented by multiple samples, received high support values (99—100%). We describe six of these as new species: 1) 7. huuskonenii sp. nov., represented by four specimens, 2) 7’ pseudoauruntii sp. nov. with two specimens, 3) 7! sallaense sp. nov., with one specimen 4) 7. toskalhar- jiense sp. nov., including six specimens, 5) 7’ declivum sp. nov., with nine specimens and 6) 7’ mendax sp. nov., with four specimens. Based on morphological charac- ters, the first four species belong to the 7) auruntii complex, while T’ declivum and I) mendax are members of the 7’ incavatum complex. The two remaining lineages, both represented by only one specimen, are named here as Thelidium sp. 1 and Thelidium sp. 2. Thelidium sp. 1 resembles 7! auruntii, whereas Thelidium sp. 2 is morphologically similar to 7’ incavatum. Both lineages most likely represent new species, although more specimens with similar morphology are needed before their status can be discussed further.

6 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Based on the ITS phylogeny, the study species belong to the Thelidium group in the sense of Gueidan et al. (2009). Neither of the two morphocomplexes is resolved monophyletic. Instead, the ingroup is divided into three main subclades. ‘The first subclade is strongly supported (93%) and includes 7’ methorium, T: pertusatii and L. pyrenophorum in addition to the three species of the 7’ auruntii morphocomplex, i.e., [. auruntii, 1. pseudoauruntii sp. nov. and T. sallaense sp. nov. An unnamed lineage Thelidium sp. | belongs to this clade as well. Thelidium auruntii and T. pseudoauruntii form a strongly supported group (89%) and T° sallaense is resolved as basal to them, although with low support (59%).

The second subclade remains unsupported and includes nine species in addition to one unnamed Verrucaria obtained from Genbank. Thelidium declivum sp. nov. and 7’ mendax sp. nov., both belonging to the 7’ incavatum morphocomplex, form a strongly supported clade within this group. The second group also includes two new species, 7’ huuskonenii and T. toskalharjiense, which morphologically resemble 7) au- runtii and its allies.

The remaining two lineages of the 7’ incavatum morphocomplex, i.e., T’ incavatum and Thelidium sp. 2, are clustered in the third subclade. The subclade remains unsup- ported and includes also four Polyblastia, two unidentified Polyblastia, two Thelidium and nine Verrucaria species, all retrieved from GenBank.

The results show low infraspecific variation in the ITS sequences of the study spe- cies. All specimens of 7’ declivum (n = 9), I) huuskonenii (n = 4), T’ mendax (n = 4) and LT. pseudoauruntii (n = 2) have identical ITS sequences. Low variation (> 99% simi- larity) between all specimens is also found in other species with the exception of one specimen of T° incavatum, which has only 98.5% similarity with the other specimens belonging to the same species.

Most of the species are restricted to calcareous rocks of northern Finland. Thelidium huuskonenii, T. toskalharjiense and T.: sp. 1 have been found only from the calcareous fells of Enontekié in NE Finland; 7 declivum, T’ pseudoauruntii and T. sallaense only from the Oulanka area (parishes Kuusamo and/or Salla) in NE Finland. Thelidium mendax occurs in the Oulanka area with one locality in eastern central Finland. Thelidium auruntii occurs both in Enonteki6é and the Kuusamo-Salla area. Thelidium sp. 2 has been found from one locality in SW Lapland. Thelidium incavatum is the only species with southern distribution in Finland, occurring widely in SW Finland. One separate locality is in central eastern Finland.

Discussion

The dominance of northern distribution within the study species may explain why most of them have remained undescribed. Only a few Thelidium species have been described from northern Europe and none from the calcareous fells. Particularly the crustose lichen flora of calcareous rocks in the fells of northern Finland is rather poorly known (Pykala 2010a). Pyrenocarpous lichens in the calcareous fells of Sweden and

Taxonomy of Thelidium auruntii and T. incavatum complexes 7

Norway are also poorly collected (Magnusson 1952). It remains to be studied wheth- er our new species occur more widely in the Scandinavian Mountains and in other northern mountains.

Species restricted to calcareous fells and/or the Oulanka area may be particularly sensitive to climate change. Northern lichen species may not be directly limited by temperatures but may be poor competitors, sensitive to the increase of other species benefitting from increased temperatures, particularly vascular plants (Alatalo et al. 2017; Greiser et al. 2021). For such species, retarding the dispersal of more southern species to the north is needed as a conservation measure of northern species against climate change (Pykala 2017).

A considerable number of new species in the study group are congruent with the previous studies of Verrucariales in Finland (Pykala and Myllys 2016; Pykala et al. 2019, 2020). This study and earlier studies suggest that the number of species in Verrucariales in northern Europe is much higher than is presently known. We could find previously published names for only two of the species. This suggests that Fennoscandian and Central European species composition of the group under study differs greatly from each other. Similar results have been obtained among other previously studied groups of Verrucariales (e.g., Savi¢é and Tibell 2012; Pykala et al. 2017 a,b; 20195-2020).

Taxonomy

The species descriptions are based on the sequenced specimens collected in Finland.

Thelidium auruntii (A. Massal.) Kremp., Denkschr. Kgl. Bayer. Bot. Ges. 2(4): 248 (1861).

Verrucaria auruntii A. Massal., Symmict. Lich. 77. (1855). Basionym.

Type. [Italy] ad saxa dolomitica in opp. Auronzo (Col della Favola) (VER)).

Description. Prothallus not visible. Thallus pale brownish grey to pale greyish brown, rarely medium brown, continuous to rimose, rarely areolate, up to 0.2 mm thick, in one specimen surrounded by one dark line, algal cells c. 6-11 pm. Perithecia 0.21—0.38 mm in diam., 1/2—3/4-immersed, not leaving pits to leaving shallow pits; c. 60-160 perithecia / cm’. Ostiole dark, plane to depressed, c. 20-50 um wide, ostiolar depression up to 120 pm wide. Involucrellum apical, exceeding half of the exciple to rarely to the exciple base level, 30-80 um thick, appressed to the exciple or to clearly diverging from it. Exciple 0.16—0.29 mm, wall pale to dark brown (usually brown), c. 17-20 pm thick. Periphysoids c. 20-40(—50) x 1.5—2 um. Asci c. 62-72 x 26-32 um, 8-spored. Ascospores 0—1-septate, (20.3—)24.5—26.9-29.2(—32.1) x (9.2-)10.6-11.5- 12.4(-13.3) um (n = 86).

8 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Habitat and distribution. The species occurs in northern Finland in Enontekié, Kuusamo and Salla parishes on dolomite rock outcrops, boulders, stones and peb- bles. Several collections come from the calcareous fells of Saana and Toskalharji in Enontekio. In the biogeographical province Koillismaa, the species is very rare, and it has been confirmed only from two localities (one in Kuusamo and one in Salla). The species grows mostly on dry sun-exposed calcareous rocks. However, some localities on river and brook shores are probably periodically submerged.

Notes. The Finnish specimens are included in 7’ auruntii, because no clear mor- phological differences between the type of 7’ auruntii and the Finnish specimens were found. However, the type has slightly shorter spores: 20-26 x 10-14 pm. The type of TZ. auruntii is from the Dolomites in northern Italy. It is possible that 77 auruntii is an arctic-alpine species. Sequences from the Dolomites are needed to confirm whether the Finnish specimens are conspecific with 7’ auruntii.

Pykala (2007) reported the species as 7’ pyrenophorum (Ach.) Korb. from Finland, but the specimens differ morphologically from 7’ pyrenophorum (type: Helvetia, H- ACH-685!). The type of 7! pyrenophorum differs in larger perithecia: 0.35—0.7 mm. According to our ITS phylogeny, the two species are rather closely related (Fig. 1) if the GenBank specimen of 7’ pyrenophorum from Sweden is correctly identified. Thelidium methorium (Nyl.) Hellb. is characterised by large perithecia, thick involucrellum, larger spores (mean 34 x 14 um) and occurrence on siliceous rocks (Thiis and Nascimbene 2008; Orange 2013). Thelidium pertusatii (Garov.) Jatta resembles 7’ methorium but has a very thick involucrellum (110-170 um thick) (Thiis and Nascimbene 2008). ‘The differences between closely related 7’ pseudoauruntii and T. sallaense are discussed below.

Several other Thelidium species are morphologically rather similar to 7) auruntii. Thelidium incinctum (Vain.) Vain. (Finland, Kuusamo, Porontimajarvi, 12.8.1867, ESileni (H!, H-NYL6941, syntypes)) differs in thicker involucrellum (70-80 um thick), larger spores (25—38 x 12—15 um) and occurrence on siliceous rock. It is only known from the type collection. Thelidium bubulcae (A.Massal.) Arnold described from Italy (ad saxa ipocretacea (Preapura) M. Bolca (M. Colle), 1854, A.Massalongo (VER!); Veneto; ad saxa arenacea oppidi Bolca (M. Colle) in prov. Veronensi Massalongo, Anzi: Lich. Rar. Veneti 136 (UPS-L-686416!, syntypes?) is rather similar to 7’ auruntii but may possibly differ by shorter, apical involucrellum and areolate thallus. 7helidium lacromense Zschacke ([Croatia] ins. Lacroma: An frei liegenden Gestein, c. 10 m, Kalk, 11.9.1907, A.Latzel (PRM-858048!, syntype)) is morphologically similar to 77 au- runtii, but the type locality is close to sea level in Croatia and thus not likely to belong to the same species as the Finnish material of 7’ auruntii. Thelidium athallinum Servit (Slovakia, Vysoké Tatry, monte Tokarna, supra saxa conglom., 1100-1200 m, 1925, Suza (PRM-858571!, syntype)) differs in thicker involucrellum (c. 80-100 um thick).

Other specimens examined. FINLAND, Koillismaa, Salla, Oulanka National Park, 400 m N of Savilampi, shore of river Savinajoki, dolomite rock outcrop, on NE-slope, 177 ma.s.l, 66°25'N, 29°10'E, 13 August 2009, J.Pykala 36339 (H); Kuusamo, Ou- lanka National Park, Mataraniemi, shore of Oulankajoki river, treeless stony river shore, on dolomite stones, 145 m a.s.l, 66°22'N, 29°20'E, 26 August 2011, J.Pykala

Taxonomy of Thelidium auruntii and T: incavatum complexes 9

Polyblastia albida EU553492

Polyblastia fuscoargillacea EU553498 Thelidium pyrenophorum EU553500

93

97

75

63 100

57

82

51

0.04

Thelidium methorium MT127220 98 T. methorium FJ645267 100 , Thelidium pseudoauruntii 45374 T. pseudoauruntii 45371 89 Thelidium auruntii 43905 T. auruntii 36339 100] 7. auruntii 45171 T. auruntii 43829 T. auruntii 43446

59 T. auruntii 43414

641 + auruntii 43470 Thelidium sallaense 44902 Thelidium pertusatii EU249471 Thelidium sp.1 43208 Verrucaria vacillans MT229831 Verrucaria pallidomurina MT127221 Verrucaria sp. MT127205 Verrucaria deversa EU553496 Thelidium toskalharjiense 43848 T. toskalharjiense 43364 100 | &. toskalharjiense 43211 T. toskalharjiense 43398 T. toskalharjiense 43090 T. toskalharjiense 43861 Verrucaria latebrosa FJ664864 Thelidium huuskonenii 44167 100 T. huuskonenii 43243 T. huuskonenii 43246 T. huuskonenii 31576 Verrucaria anziana FJ664835 Thelidium declivum 39997 T. declivum 39780b T. declivum 39640 T. declivum 40037 T. declivum 36334 99 T. declivum 40047 T. declivum 45123 95 T. declivum 44554 T. declivum 35996 99 Thelidium mendax 40152 T. mendax 39179 T. mendax 42503 T. mendax 42502 Verrucaria tephromela MT127212 Verrucaria calkinsiana KT695332 Verrucaria bifurcata MT229720 Verrucaria difficilis MT229743 Verrucaria subtilis MT229810 Verrucaria cavernarum MT229724 Verrucaria subdevergens MT229782 Verrucaria devergens MT229741 Verrucaria karelica MT229762 Polyblastia abscondita EU553507 Thelidium sp.2 52038 Polyblastia sp. EU553519 54 Polyblastia clandestina EU559740 6 Polyblastia moravica EU553522 Polyblastia lutosa EU559734 90, Polyblastia sp. EU553503 71]! Thelidium incavatum 38399 T. incavatum 36867 53] | 7. incavatum 37971 T. incavatum 46459 100 T. incavatum 42871 T. incavatum 36857 IOI T. incavatum 35282 T. incavatum 34722 95 T. incavatum 38227 Verrucaria kuusamoensis MT229774 100 Thelidium umbilicatum EU559737 Thelidium papulare MT127197 Verrucaria aethiobola MT127203

(ee)

Figure |. Phylogenetic relationships of the studied species. Strict consensus based on ITS data set with bootstrap values (>50%) at nodes. New species described in this study are indicated in bold.

45171 (H); Enontekién Lappi, Enontekio, Porojarvet, Toskalharji, Toskaljarvi N, fell, dried old brook bottom, stony bottom, on dolomite pebbles, 707 m a.s.l., 69°11'N, 21°26'E, 3 August 2011, J.Pykala 43414 (H); Enontekié, Porojarvet, Toskalharji, Toskaljarvi 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.Pykala 43446 (H); Enontekié, Porojarvet, Toskal-

harji, Toskaljarvi N, fell, brook, W-shore, dolomite rock outcrop, on dolomite stones,

10 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

710 ma.s.l, 69°11'N, 21°26'E, 3 August 2011, J.Pykala 43470 (H); Enontekio, Poro- jarvet, Toskalharji, Toskaljarvi N, gentle SE-slope, alpine grassland, on dolomite boul- der, 705 m a.s.l, 69°11'N, 21°26'E, 3 August 2011, J.Pykala 43829 (H); Enontekis, Kilpisjarvi, Saana, nature reserve, W-part, fell, dolomite rock outcrop, on SW-facing

wall, 695 ma.s.l, 69°03'N, 20°48'E, 9 August 2011, J.Pykala 43905 (H).

Thelidium declivum Pykala & Myllys, sp. nov. MycoBank No: 846775 Figs 2A, 3H, I

Diagnosis. Differing from 7’ incavatum by the perithecia often less immersed in rock, the involucrellum present in most perithecia and the exciple wall is thicker, most dif- ficult to separate from 7! mendax but the involucrellum on average is shorter.

Type. FINLAND, Koillismaa, Salla, Oulanka National Park, 400 m N of Savilampi, shore of river Savinajoki, dolomite rock outcrop, on NE-slope, scarce, 178 m a.s.l, 66°25'N, 29°10'E, 13 August 2009, J.Pykala 36334 (H-9204893, holotype, UPS, iso- type, GenBank accession number: OP901851).

Description. Prothallus not visible. Thallus white, grey or pale brown, endolithic to rarely thinly epilithic, algal cells c. 5—8 um, in one specimen (type) surrounded by dark lines. Perithecia 0.12—0.44 mm in diam., 1/2—1-immersed, often surrounded by thalline collar, leaving shallow to usually deep pits; c. 20-80 perithecia / cm’. Ostiole pale to dark, plane to depressed, c. 20-50 um wide. Involucrellum absent, apical or covering half of the exciple, 0-70 pm thick, appressed to the exciple or clearly diverg- ing from it. Exciple 0.22—0.38 mm, wall dark brown to black, c. 25—40 um thick, apex may be thickened to 50-70 um thick. Periphysoids c. 30-50 x 1.5—2.5 um. Asci c. 91-132 x 31-48 um, 8-spored. Ascospores (1—2—)3-septate, few spores submuriform with 5—G6(—8) cells, (32.3-)35.3-37.8-40.4(-44.4) x (12.6-)14.0-15.0-16.1(—17.3) um (n = 69).

Habitat and distribution. The species occurs in NE Finland, in the parishes of Kuusamo and Salla, on dolomite rock outcrops and boulders. The species may prefer rather shady habitats. Most localities are close to river shores.

Etymology. ‘The species prefers steep rock outcrops.

Notes. This species was previously reported from Finland as 7? larianum A. Massal. (Pykala 2010b). The type specimen of 77 larianum A. Massal. (in calcaris ubique, Ga- rovaglio, VER!) is in poor condition, and thus, the identity of the species cannot be solved. According to Zschacke (1934), the spore size of 7’ larianum is smaller: 25-36 x 11-15 um than the size in the Finnish specimens. The protologue (Massalongo 1855): “in circa Larium Lacum ad saxa calcareo-bituminosa Clar. Prof. Garov.”, i.e., the local- ity is close to Lake Como, and the collector is S. Garovaglio. Thus, the climatic condi- tions of the type locality are likely to strongly differ from those in NE Finland, and it is likely that the Finnish specimens do not belong to 7 Jarianum. Based on the Finnish distribution, it could be assumed that 7’ declivum may be an eastern species, which has its main distribution in Russia and/or in North America.

Taxonomy of Thelidium auruntii and T. incavatum complexes il

Figure 2. A Thelidium declivum (holotype) B 7’ huuskonenii (holotype) C T mendax (holotype) D 7. pseudoauruntii (holotype) E T. sallaense (holotype) F T. toskalharjiense (holotype). Scale bars: 1 mm (A-C, E, F); 0.5 mm (D).

Polyblastia torrentis Servit (Sweden. Torne Lappmark: Jukkasjarvi par., Abisko, Re- gio subalpina by the torrent, alt. 400 m, 29.7.1921, A.H.Magnusson; UPS!, syntype) differs in less immersed perithecia (1/4—1/2-immersed) leaving shallow pits. Exciple may also be smaller (in studied perithecia c. 0.2-0.22 mm), but according to Servit (1953) the size of the exciple is c. 0.3 mm.

Thelidium declivum is difficult to separate from T’ incavatum and the closely related TL) mendax. Thelidium incavatum has predominantly fully immersed perithecia, and 3/4-immersed perithecia are usually overmature, whereas 7’ declivum has predomi- nantly 3/4—immersed perithecia. Furthermore, the involucrellum is absent from most specimens of 77 incavatum, whereas the involucrellum occurs in most perithecia, and in all studied specimens of 7’ declivum. Thelidium incavatum also has a thinner exciple

12 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

wall: c. 15-25 um thick. Thelidium mendax may differ in longer involucrellum, but more material is needed to determine whether this character can be used to separate the species from 7’ declivum.

Other specimens examined. FINLAND, Koillismaa, Kuusamo, Oulanka, Putaano- ja, 500 m W-NW of Hautala, dolomite rock outcrop, beneath N-facing wall, on boulder, 228 m a.s. |., 66°22'N, 29°25'E, 9 August 2009, J.Pykala 35996 (H); Salla, Oulanka National Park, Savikoski 300 m N, shore of lake Savilampi, calciferous (do- lomite) schistose rock outcrop, on N-facing wall, 175 m a.s.l, 66°25'N, 29°10'E, 10 August 2010, J.Pykala 39640 (H); Salla, Oulanka National Park, Savilamminniemi, shore of lake Savilampi, cliff, calciferous (dolomite) schistose rock outcrop, on S-facing wall, 172 ma.s.l, 66°25'N, 29°10'E, 12 August 2010, J.Pykala 39780b (H); Kuusamo, Oulanka, Putaanoja, 500 m W-NW of Hautala, dolomite rock outcrop, on NE-facing wall, 230 m a.s.l., 66°22'N, 29°25'E, 15 August 2010, J.Pykala 39997 (H), 40037 (H), 40047 (H); Kuusamo, Oulanka National Park, Taivalkoéngas, shore of Oulanka- joki river, Picea abies-dominated herb-rich forest, dolomite rock outcrop, NE-slope, on dolomite boulder, 174 m a.s.l, 66°24'N, 29°11'E, 20 August 2011, J.Pykala 44554 (H); Kuusamo, Oulanka National Park, Taivalkongas, shore of Oulankajoki river, do- lomite rock outcrop, on NW-facing wall, 165 m a.s.l, 66°24'N, 29°11'E, 25 August 2011, J.Pykila 45123 (H).

Thelidium huuskonenii Pykala & Myllys, sp. nov. MycoBank No: 846776 Figs 2B, 3A, B

Diagnosis. Species morphologically rather similar to 77 auruntii, but the spores small- er, perithecia often leaving deep pits, and the thallus predominantly endolithic.

Type material. Holotype. Fintanp, Enontekién Lappi, Enontekié, Kilpisjarvi, Saana, fell, steep NE-slope, dolomite rock outcrop, on NE-facing wall, abundant, 820 m a.s.l, 69°02'N, 20°51'E, 11 August 2011, J.Pykala 44167 (H9204900, Gen- Bank accession number: OP901862).

Description. Prothallus not visible. Thallus white to grey, endolithic to thinly epilithic, only surrounding perithecia, algal cells, c. 4-7 um, in one specimen sur- rounded by one dark line. Perithecia 0.18—0.32 mm in diam., (1/2—)3/4—1-immersed, leaving shallow to deep pits; c. 80-120 perithecia / cm’. Ostiole pale to dark, plane to depressed, c. 20—40 pm wide. Involucrellum absent, apical or covering half of the exciple, 0-60 pm thick, appressed to the exciple or clearly diverging from it. Exciple 0.20—-0.28 mm, wall dark brown to black, c. 15-20 um thick, apex may be thickened to 50-80 um thick. Periphysoids c. 20-45 x 1.5—2 um, branching. Asci c. 58-74 x 22-25 um, 8-spored. Ascospores (0—)1-septate, (16.4—)18.2—20.7—23.2(—27.6) x (8.0—-)8.6-9.9-11.2(-14.4) um (n = 69).

Habitat and distribution. Four specimens have been confirmed by sequencing, but more than twenty morphologically similar specimens have been collected from the calcareous fells of Saana and Toskalharji. The species seems to occur only in northern

Taxonomy of Thelidium auruntii and T: incavatum complexes 13

“OY |

OQ

C

JAY

e

J | Figure 3. Drawn anatomical features of the newly described Thelidium species. Represented perithe- cial features are similar between 7 uuskonenii and 1. toskalharjiense, as well as between 7. declivum and T. mendax; therefore, they are shown combined. Spores are represented as intermediate size for all species A perithecia of 7’ huuskonenii and T. toskalharjiense combined B spores of 7’ huuskonenii C spores of T. toskalharjiense D perithecium of 7) pseudoauruntii E spores of T’ pseudoauruntii F perithecium of T. sal-

laense G spores of T’ sallaense H perithecia of 7’ declivum and T’ mendax combined I spores of 7. declivum J spores of 7’ mendax. Scale bars for perithecia are 100 pm, and for spores 20 ym. Illustration: A. Kantelinen

14 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Finland, in Enonteki6 on fells on dolomite rock outcrops, boulders, stones and peb- bles. It grows on southern and northern slopes and on rather flat surfaces. ‘The altitu- dinal range is 705-890 m a.s.l.

Etymology. The species is named after A.J. Huuskonen, the Finnish amateur li- chenologist, who most intensively collected lichens from the Enonteki6 area.

Notes. ‘The species differs from 7’ auruntii in smaller spores, perithecia often leaving deep pits and thinner, predominantly endolithic, thallus. The species has been previously reported from Finland as 7! decussatum (Pykala 2010a). The Finnish specimens have sim- ilar perithecia and involucrellum as 7’ decussatum. However, T. decussatum ([Germany] Trier, 1862, Mezler, Rabenhorst Lichenes Europaei 646 (UPS!, syntype)) has a rimose thallus and the spores may be slightly larger (20-25 x 10-11 um). Furthermore, the type locality is in a temperate zone in lowland Germany. Phytogeographically, it is unlikely that such species would occur only in fells in the northwestern most part of Finland. Thelidium stenosporum Servit (Slovakia: Bielské Tatry: in rup. calc. in convalle Domintv dul, ... m. Havran ... norg, 1700 m, 1937, Suza (PRM-858497!, syntype)) has smaller perithecia and narrower spores. Thelidium bubulcae (A.Massal.) Arnold (syntypes: VER, UPS-L-686416!)) has larger rimose to areolate thallus, larger perithecia (0.2-0.37 mm) and larger spores: 20-27 x 9-13 um. Thelidium polycarpum Servit (Montenegro, Lovéen, Ljubin potok, 1230 m, 1929, Servit (PRM-858491!, holotype)) has smaller perithecia (0.13-0.23 mm) and spores (15-23 x 8-9 um). Thelidium klementii Servit has rather thick rimose to areolate thallus and slightly larger spores and is only known from a tem- porarily inundated calcareous rock (Thiis and Nascimbene 2008).

Other specimens examined. FINLAND. Enontekién Lappi, Enonteki6, Kilpisjarvi, Saana fell, Saana nature reserve, low arctic zone, on SW-facing wall of dolomite rock outcrop, 880 m a.s.l., 69°02'N, 20°51'E, 27 July 2007, J.Pykala 31576 (H); Enon- tekid, Porojarvet, Toskalharji, Toskaljarvi N, fell, dolomite rock outcrop, on S-slope, 730 m a.s.l, 69°12'N, 21°26'E, 2 August 2011, J.Pykala 43243 (H); Enontekio, Po- rojarvet, [oskalharji, Toskaljarvi N, fell, dolomite rock outcrop, on dolomite pebbles,

735 ma.s.l, 69°12'N, 21°26'E, 2 August 2011, J.Pykala 43246 (H).

Thelidium incavatum Nyl. & Mudd, Man. Brit. Lich. 295 (1861)

= Thelidium anisomerum Hellb., Kgl. Svensk. Vet. Akad. Handl. 9(11):34 (1871). Type. Sweden, Gotland, Linde klint, C.Stenhammar (S-L-347!); Gotland in colle calcareo ad Linde, Stenhammar 34 (S-L-250!), syntypes.

= Thelidium decipiescens Vain., Acta Soc. Fauna Flora Fenn. 49(2): 129 (1921). Type. Finland, Ab, Finby [= Varsinais-Suomi, Salo, Sarkisalo], Forby, in rupe calcaria, 20 August 1920, E.Vainio (TUR-V}).

= ?Polyblastia sepulta A.Massal., Lotos 6: 81 (1856). Type: [Italy,] Circa Veronam ad saxa eocenica, A.Massalongo (VER!, syntype).

Type. [England] 282. Bilsdale, Yorkshire, W.Mudd (M-0207325!, syntype?).

Taxonomy of Thelidium auruntii and T! incavatum complexes 15

Description. Prothallus not visible. Thallus white to grey, endolithic, in two speci- mens partly epilithic, slightly rimose, up to 0.1—0.15 mm thick, algal cells c. 4-6 um. Perithecia 0.06—0.36 mm in diam., (1/2—)3/4—1-immersed, often thalline covered ex- cept apex, leaving deep pits; c. 20-160 perithecia / cm’. Ostiole pale to dark, plane, c. 20-40 um wide. Involucrellum absent or apical, c. 30—60(—90) um thick. Exciple 0.16—-0.39 mm, wall dark brown to black, c. 15—25 um thick, often with ostiolar neck, often pear-shaped. Periphysoids c. 40-50 x 1.5—2 um. Asci c. 93-122 x 33-52 um, 8-spored. Ascospores 3-septate, few spores submuriform with 5—7 cells, (32.3—)37.5— 40.9-44.3(-49.4) x (12.2-)13.7-14.9-16.2(-18.1) pm (n = 78), rarely with a per- ispore c. 1 um thick.

Habitat and distribution. The species occurs in many localities in SW Finland on calcareous rocks and in lime quarries. It occurs on south- as well as on north-facing walls and on gentle slopes. More rarely, it grows on boulders, stones and pebbles. At present, more than 50 localities are known. Most localities are in the hemiboreal veg- etation zone, a few in the southern boreal vegetation zone, only some tens of kilome- tres north of the limit of the hemiboreal zone. However, one separate locality occurs in Kuopio (former Juankoski) in eastern central Finland. Thelidium incavatum may be the most common species of Thelidium in SW Finland, together with 7) minutulum Korb.

Notes. The observed syntype of Polyblastia sepulta is somewhat similar to 7! inca- vatum, and P sepulta may be the oldest name available for the species. However, better material of P sepulta is needed to confirm it. Furthermore, it is uncertain whether T. incavatum is the correct name for the Finnish specimens. The syntype in M differs in rimose thallus. However, several localities have been included in the protologue, and the specimen in M may be untypical for 77 incavatum. The Finnish specimens fit well with the description of T’ incavatum by Orange (2013).

If the Finnish specimens do not belong to 7. incavatum, there are two other puta- tive younger names available for them. Thelidium decipiescens was described from SW Finland (Vainio 1921) and is morphologically similar to the sequenced Finnish speci- mens of 7 incavatum. Already Vainio (1921) considered T’ decipiescens to be similar to some material of 7! incavatum. Thelidium anisomerum Hellb., described from Sweden, is also similar to 7. incavatum.

Thelidium bavaricum Dalla Torre & Sarnth. has broader spores (Germany, Bavaria, an den aus den begrasten Boden hervorstehenden Dolomitblécken oberhalb des Tie- fenthales bei Eichstatt, April 1859, Arnold, in Arnold: Lich.. Exs. 87 (UPS-L-165297!, syntype): 30-48 x 15—20 um, and submuriform spores may be more frequent.

The ITS sequence of the 7’ incavatum specimen, collected in the separate locality in eastern Finland, differs from the other sequenced specimens (98.5% similarity). The specimen also differs morphologically from the other specimens by less immersed peri- thecia (1/4—1/2-immersed) and thicker involucrellum (c. 70-90 um thick). The spores may also be slightly shorter: 28.1—35.7 x 12.8-15.4 um (n=15). It may represent a separate species but is now included in 7’ incavatum, awaiting more material.

Other specimens examined. FINLAND, Varsinais-Suomi, Parainen (Korppoo), Afvensar, Kalklot island, calcareous rock outcrop on shore of the Baltic Sea, E-slope,

16 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

on pebbles, 5 m a.s.l., 60°18'N, 21°31'E, 27 July 2009, J.Pykala 35282 (H); Salo (Sarkisalo), Férby, 200 m S of lime factory, calcareous rock outcrop, on SW-slope, 60°05'N, 22°52'E, 8 September 2009, J.Pykala 36857 (H); Salo (Sarkisalo), Forby, 200 m S of lime factory, abandoned lime quarry, on 40 cm high NW-facing wall, 18 ma.s.l, 60°05'N, 22°52'E, 8 September 2009, J.Pykalaé 36867 (H); Parainen (Ini6), Séderby, Biskops6 island, calcareous rock outcrop on shore of the Baltic Sea, on N- slope, 8 ma.s.l, 60°20'N, 21°28'E, 9 June 2010, J.Pykala 37971 (H); Parainen (Korp- poo), Elfsj6, Stora Limskar island, shallow abandoned lime quarry, on N-facing wall, 6 m as.l., 60°09'N, 21°26'E, 21 June 2010, J.Pykala 38227 (H); Parainen (Hout- skari), Bjorks, Ostra Langholm, Norrnas, siliceous rock outcrop on shore of the Bal- tic Sea, NW-slope, on narrow calcareous vein, scarce, 9 m a.s.l., 60°15'N, 21°26'E, 29 June 2010, J.Pykala 38399 (H); Parainen, Petteby, Kalkudden, abandoned lime quarry, on W-facing wall, 18 m a.s.l., 60°17'N, 22°10'E, 5 October 2011, J. Pykala 46459 (H); Uusimaa, Hyvinkaa, Myllykyla, Kalkkikallio, abandoned lime quarry, on N-facing wall, 100 m a.s.1, 60°36'N, 25°03'E, 7 July 2009, J.Pykala 34722 & H. Rama (H); Pohjois-Karjala, Kuopio (Juankoski), Siikajarvi, Huosiaisniemi, nature reserve, dolomite rock outcrop on shore of lake Ala-Siikajarvi, on gentle NE-slope, scarce,

97 ma.s.l., 63°12'N, 28°21'E, 26 July 2011, J.Pykala 42871(H).

Thelidium mendax Pykala & Myllys, sp. nov. MycoBank No: 846777 Pies 2@ 3b, \

Diagnosis. Species morphologically rather similar to 7’ declivum and T. incavatum, but the involucrellum is on average longer.

Type material. Holotype. FINLAND, Koillismaa, Salla, Oulanka National Park, Pikkuk6ngias, shore of river Oulankajoki, high cliff, calciferous (dolomite) schistose rock outcrop, W-facing wall, on dolomite patch, 180 m a.s.l, 66°25'N, 29°08’'E, 4 August 2010, J.Pykala 39179 (H-9206536, GenBank accession number: OP901872).

Description. Prothallus not visible. Thallus white to pale brown, endolithic to weakly rimose, algal cells, c. 4-7 um. Perithecia 0.18—0.38 mm in diam., 1/2—1-im- mersed, often surrounded by thalline collar, leaving shallow to deep pits; c. 20-60 perithecia / cm’. Ostiole pale to dark, plane, c. 20-60 um wide. Involucrellum apical to exceeding half of the exciple, c. 40-80 pm thick, appressed to the exciple or clearly diverging from it. Exciple 0.18—0.36 mm, wall dark brown to black, rarely pale, c. 20-30 um thick. Periphysoids c. 40-60 x 1.5—2.5 um. Asci c. 90-128 x 31-43 um, 8-spored. Ascospores 3-septate, (34.8—)36.1—40.1-44.1(—51.0) x (11.8-)12.8-13.4— 14.0(-14.9) um (n = 48), perispore 1-1.5 um thick in few spores.

Habitat and distribution. The species is known from three localities, two in NE Finland, in the parishes Kuusamo and Salla, and one in Juuka in central eastern Finland. Thelidium mendax grows on calcareous rocks and calciferous (dolomite) schistose rocks. Two collection sites are affected by spring flooding and may periodically be submerged.

Taxonomy of Thelidium auruntii and T: incavatum complexes 17

Etymology. ‘The species is easily misidentified.

Notes. Based on the ITS phylogeny, this species is closely related to 7’ declivum. It is also morphologically difficult to separate from that species. Thelidium mendax has, on average, longer involucrellum than in 7! declivum. Thelidium mendax is here kept separated from 7! declivum because this solution received high support value in the ITS phylogeny (99%). Within the species 7’ declivum and T’ mendax have identical ITS sequences and the species have a clear barcoding gap (3% difference).

Polyblastia torrentis (Sweden. Torne Lappmark: Jukkasjarvi par., Abisko, Regio subalpina by the torrent, alt. 400 m, 29 July 1921, A.H.Magnusson (UPS!, syntype)) differs in less immersed perithecia (1/4—1/2-immersed) and thinner involucrellum (c. 30-40 um thick).

Other specimens examined. FINLAND, Koillismaa, Kuusamo, Juuma, Oulanka National Park, Jakalavuoma, gorge, calciferous (dolomite) schistose rock outcrop, on bottom, shore of a pond, on dolomite coated stone, 200 m a.s.l., 66°15'N, 29°26'E, 16 August 2010, J.Pykala 40152 (H); Pohjois-Karjala, Juuka, Petrovaara, Riihilahti S, calcareous rock outcrop, on W-facing wall, 190 m a.s.l, 63°09'N, 28°58'E, 13 July 2011, J.Pykala 42502 (H), 42503 (H).

Thelidium pseudoauruntii Pykala & Myllys, sp. nov. MycoBank No: 846779 Figs 2331). &

Diagnosis. Species morphologically rather similar to 7’ auruntii, but the spores are smaller and the perithecia tend to be less immersed.

Type material. Holotype. FINLAND, Kollismaa, Kuusamo, Oulanka National Park, Mataraniemi W, shore of Oulankajoki river, small dolomite rock outcrop, on SE- slope, 147 m a.s.l, 66°22'N, 29°20'E, 28 August 2011, J.Pykala 45374 (H9220350, GenBank accession number: OP901877).

Description. Prothallus not visible. Thallus pale greyish brown to medium brown, endolithic to rimose, algal cells c. 5~7 um, with one dark brown thalline line. Perithe- cia 0.18—0.36 mm in diam., 1/4—1/2-immersed, not leaving pits to leaving shallow pits; c. 50-140 perithecia / cm’. Ostiole dark, depressed, c. 20-50 um wide. Invo- lucrellum covering half of the exciple, c. 40-70 um thick, appressed to clearly di- verging from the exciple. Exciple c. 0.17—0.24 mm, wall pale brown to usually dark brown, c. 15—20 um thick. Periphysoids c. 20-25 x 2 um. Asci c. 64-83 x 22-32 um, 8-spored. Ascospores 0—1-septate, (21.3—)23.9-25.1—26.2(—26.6) x (8.6—-)9.2-10.1- 11.0(-12.2) um (n = 23), perispore 1 um thick present in some spores.

Habitat and distribution. The species is only known from the type locality on small dolomite rock outcrop on the rivershore. The locality is likely to be under water during spring floods. Potentially suitable habitats for the species may be very rare in Finland.

Etymology. ‘The species resembles morphologically 7’ auruntii and is also closely related to the species based on the ITS sequences.

18 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Notes. The species is closely related to 7’ auruntii and T. sallaense. Only two speci- mens are known and from the same locality. We prefer to treat 7’ pseudoauruntii as a species separate from 7! auruntii because of high support value (100%) in the ITS phylogeny. Furthermore, there is a clear barcoding gap (3%) between the species. The species have also different distribution areas. Thelidium pseudoauruntii seems to be absent from the calcareous fells of NW Finland, i.e., from the main distribution area of 77 auruntii in Finland. Thelidium pseudoauruntii may be an eastern species with the main distribution area in North America and/or Russia. The specimens of 7’ pseu- doauruntii have smaller spores than in 7’ auruntii and T: sallaense. Furthermore, the perithecia are less immersed. However, more material is needed to determine whether the species differs unambiguously morphologically from the related species.

Other specimens examined. FINLAND, Koillismaa, Kuusamo, Oulanka National Park, Mataraniemi W, shore of Oulankajoki river, small dolomite rock outcrop, on

dolomite stones, 145 ma.s.l., 66°22'N, 29°20'E, 28 August 2011, J.Pykala 45371 (H).

Thelidium sallaense Pykala & Myllys, sp. nov. MycoBank No: 846780 Figs 2E, 3F, G

Diagnosis. Species morphologically rather similar to 7’ auruntii, but the thalli may be more brown-pigmented.

Type material. Holotype. FINLAND, Koillismaa, Salla, Oulanka National Park, Savilampi 1,4 km NE, shore of Savinajoki river, river shore, on dolomite stone, 185 m a.s.l., 66°26'N, 29°11'E, 23 August 2011, J.Pykala 44902 (H9220340, GenBank ac- cession number: OP901878).

Description. Prothallus not visible. Thallus pale brown to medium brown, rimose, algal cells c. 5-8 um. Perithecia 0.21—0.28 mm in diam., 3/4(—1)-immersed in thal- lus, not leaving pits; c. 60-80 perithecia / cm’. Ostiole brown, plane to depressed, c. 20-60 um wide. Involucrellum apical, c. 40-50 um thick, slightly diverging from the exciple. Exciple c. 0.16—0.27 mm, wall pale to brown, K+ olive. Periphysoids c. 20-30 x 2 um. Asci c. 67-83 x 25-32 um, 8-spored. Ascospores (0—)1-septate, (26.3—)27.3— 28.8—30.2(—31.1) x (12.0-)12.2-12.6-12.9(—13.4) um (n = 12), perispore 1 wm thick present in some spores.

Habitat and distribution. The species is only known from the type locality grow- ing on dolomite stone on a rivershore. ‘The species is likely to be very rare and threat- ened in Finland.

Etymology. The name is according to the parish Salla from where the only known specimen has been collected.

Notes. More material is needed to solve whether the species can be morphologi- cally separated from 7) auruntii. It may differ from 7! auruntii by a more clearly brown pigmented thallus.

Taxonomy of Thelidium auruntii and T: incavatum complexes 19

Thelidium toskalharjiense Pykala & Myllys, sp. nov. MycoBank No: 846781 Figs 2F, 3A, C

Diagnosis. Species morphologically rather similar to 7’ auruntii, but the spores are larger, and the involucrellum is, on average, shorter and thinner.

Type material. Holotype. FINLAND, Enontekion Lappi, Enontekio, Porojarvet, Toskalharji, Toskaljarvi N, fell, stony lake shore, on dolomite stones, 705 m a.s.l., 69°11'N, 21°26'E, 3 August 2011, J.Pykala 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 um, 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 / cm’. Ostiole pale to dark, plane, c. 20-30(—60) um wide. Involucrellum apical to covering half of the exciple, 20-50 um 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 um thick. Periphysoids c. 20-30 x 2—2.5 um. Asci c. 73- 83 x 23-29 um, 8-spored. Ascospores 1-septate, (22.4—)26.8-—29.1—31.3(-35.5) x (11.8—)12.5-13.4-14.2(-16.1) um (n = 91).

Habitat and distribution. The species occurs in the fell Toskalharji in northern Finland in Enontekié within an area of three square kilometres and is divided into three subpopulations. It grows on dolomite boulders, stones and pebbles. Most speci- mens 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 7’ 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 7) auruntii may have similar involucrellum to LT. toskalharjiense. Nevertheless, based on ITS phylogeny, the species is not closely related to 7’ auruntii.

Other specimens examined. FINLAND, Enontekién Lappi, Enontekio, Poro- jarvet, Toskalharji, Toskalpahta fell, SW-slope, scree, on dolomite pebbles, 790 m a.s.l, 69°11'N, 21°29'E, 1 August 2011, J.Pykala 43090 (H); Enontekié, Porojarvet, Toskalharji, Toskaljarvi N, fell, gentle SE-slope, on dolomite boulder, 715 m a.s.], 69°11'N, 21°26'E, 2 August 2011, J.Pykala 43211 (H); Enontekis, Porojarvet, Toskal- harji, Toskaljarvi N, fell, gentle SW-slope, dolomite rock outcrop, on dolomite peb- bles, 715 m a.s.l, 69°11'N, 21°26'E, 3 August 2011, J.Pykalé 43364 (H); Enontekis, Porojarvet, Toskalharji, Toskaljarvi 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.Pykala 43848 (H); Enontekio, Porojarvet, Toskalharji, Toskaljarvi N, close by lake shore, al- pine 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.Pykala 43861 (H).

20 Juha Pykala et al. / MycoKeys 96: 1-23 (2023)

Thelidium sp. 1

Description. Prothallus not visible. Thallus whitish grey, endolithic. Perithecia 0.25— 0.33 mm in diam., 1/4—1/2-immersed, leaving shallow pits; c. 50 perithecia / cm’. Ostiole, tiny, dark, plane. Involucrellum almost to the exciple base, 30-50 um thick, may thicken to the base to c. 50-60 um thick, slightly diverging from the exciple. Ex- ciple c. 0.17—0.25 mm, wall dark brown. Periphysoids c. 25-30 x 2 um. Asci 8-spored. Ascospores 0—1-septate, 23-28 x 10-12 um.

Habitat and distribution. The specimen has been collected from a dolomite rock outcrop on a fell in northern Finland in Enontekié.

Notes. The specimen probably represents an undescribed species belonging to the 7’ au- runtii complex. However, the specimen is quite small, and thus, better material is needed.

Specimen examined. FINLAND, Enontekién Lappi, Enontekio, Porojarvet, Toskal- harji, Toskaljarvi N, fell, dolomite rock outcrop, on SW-slope, 715 m a.s.l., 69°11'N, 21°26'E, 2 August 2011, J.Pykala 43208 (H).

Thelidium sp. 2

Description. Prothallus not seen. Thallus whitish grey, endolithic. Perithecia 0.17— 0.26 mm, 3/4-immersed, leaving deep pits; c. 40-60 perithecia /cm’. Ostiole dark, plane to depressed, c. 20-40 um wide. Involucrellum absent. Exciple c. 0.26—0.32 mm, wall black, apex thickened.

Spores 3-septate, 30-37 x 16-18 um.

Habitat and distribution. ‘The only specimen has been collected from calcareous pebbles in a lime quarry spoil in SW Lapland.

Notes. ‘The specimen is small. It is morphologically similar to 7’ incavatum and probably closely related to that species, although the relationship remains unsupport- ed. The species may be undescribed but a better specimen is needed for type material.

Specimen examined. Fintanp, Kittilan Lappi, Kolari, Akasjokisuu, Mannajoki, former cement factory 200 m N-NW, lime quarry spoil, on calcareous pebbles, 165 m a.s.l, 67°27'N, 23°38'E, 16 August 2018, J.Pykala 52038 (H).

Acknowledgements

The field work was done in the research project “Threatened lichens of calcareous rocks” (Grant number YTB059). The manuscript preparation was supported by the research project “Key habitats for red-listed lichens” (Grant number 700T-MTX003). Both pro- jects belonged to the research programme of deficiently known and threatened forest species (PUTTE), financed by the Finnish Ministry of the Environment. DNA barcod- ing was supported by the Kone Foundation, the Finnish Cultural Foundation and the Academy of Finland through their grants to the Finnish Barcode of Life (FinBOL) and

Taxonomy of Thelidium auruntii and T. incavatum complexes 21

the Finnish Biodiversity Information Facility (FinBIF). We would like to thank Diana Weckman for help in the laboratory work, and Pekka Malinen, from the Zoology Unit of the Finnish Museum of Natural History, for his help with the photos. The curators of the herbaria B, G, S, UPS and W are thanked for the specimen loans. We would also like to thank Andreas Beck, Frantisek Bouda, Francesco Di Carlo and Martin Westberg for their hospitality during the visits to M, PRM, VER and UPS, respectively. Herbarium visits were supported by a grant from Societas pro Fauna et Flora Fennica. Finally, thank you to Teuvo Ahti and Starri Heidmarsson for their helpful comments on the manuscript.

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Supplementary material |

The alignment

Authors: Juha Pykala, Annina Kantelinen, Leena Myllys

Data type: PDF file

Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODDbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Link: https://doi.org/10.3897/mycokeys.96.98738.suppl1