Phylogenetic position of Synarthonia ( lichenized Ascomycota , Arthoniaceae ) , with the description of six new species

1Meise Botanic Garden, Nieuwelaan 38, BE-1860 Meise, Belgium 2University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium 3NTNU University Museum, Norwegian University of Science and Technology, Erling Skakkes gate 47A, NO-7012 Trondheim, Norway 4Département Botanique, Parc de Tsimbazaza, B.P. 4096, Antananarivo 101, Madagascar 5Fédération Wallonie-Bruxelles, Direction Générale de l’Enseignement non obligatoire et de la Recherche scientifique, rue A. Lavallée 1, BE-1080 Bruxelles, Belgium *Author for correspondence: dries.vandenbroeck@plantentuinmeise.be


INTRODUCTION
The cosmopolitan family Arthoniaceae is the largest family in the order Arthoniales, which includes about 1500 species of mainly lichenized, more rarely lichenicolous and saprophytic fungi (Ertz et al. 2009, Sundin et al. 2012, Frisch et al. 2014a).The family, first described by Reichenbach (1841), is characterized by a reduction of the ascomatal borders and by globose to clavate asci of the Arthonia-, Arthothelium-and Cryptothecia-types (Grube 1998, Frisch et al. 2014a).The family Arthoniaceae is a major component of the lichen flora of many forest types, especially in the tropics where many corticolous and foliicolous species occur (Tehler 1983, Tehler 1990, Follmann & Werner 2003, Frisch et al. 2014a).
All Synarthonia species seem to have a rather restricted distribution.Synarthonia bicolor has been mentioned only from Costa Rica (Müller 1891).Synarthonia psoromica and S. sikkimensis are currently known only from India (Joseph & Sinha 2015), while S. sarcographoides has been reported only once from north-east Brazil (Menezes et al. 2013) and S. stigmatidialis once from Mexico (Müller 1895).Most species are probably overlooked as they are rather inconspicuous in the field.Often only limited material is available, but additional specimens are possibly stored in herbaria under other names such as Arthonia sp.
During our ongoing studies on the biodiversity of lichens in tropical Africa, several specimens of the type species of Synarthonia were collected and sequenced, allowing for placing the genus in a phylogeny for the first time.Moreover, six species new to science and ten species currently placed in Arthonia could be assigned to or combined into this genus based on anatomical, chemical, morphological, ecological and/or molecular data.The new species are described below along with the new combinations.A world key to all known species is provided.A phylogenetic tree showing the position of the genus in the family Arthoniaceae is presented.

Morphological study
Specimens for this study collected by the authors in Belgium, D.R. Congo, France, Madagascar, Rwanda, Tanzania and Uganda are deposited in the herbaria of the Meise Botanic Garden (BR), the Museum of Evolution in Uppsala (UPS) and the private herbaria of R. Common and A. Frisch.Other specimens were borrowed from the following herbaria: B, BM, BR, BSA, FH, G, H, M, S, TUR, UPS, US and WU.Morphological characters were studied using an Olympus SZ61 stereomicroscope and a Leica MS5 dissecting microscope.The anatomy was studied using an Olympus CHR-TR45 and an Olympus BX51 microscope.Microscopic photographs were taken with an Olympus BX51 microscope fitted with an Olympus UC30 camera.Macroscopic photographs were taken using a Keyence VHX-5000 digital microscope.For species identification, hand sections and squash preparations of specimens were studied in water, methyl blue, 5% KOH (K), and Lugol's reagent (1% I 2 ) either without (I) or with KOH pre-treatment (K/I).Measurements of ascospores refer to material examined in water, those of asci to material examined in K/I.For measurements of asci, ascospores and conidia, the minimum and maximum values are given, all values except those of the conidia rounded to the nearest multiple of 0.5 µm, followed by the number of measurements (N).When more than 50 ascospores were measured, ascospore measurements are presented as (minimum) X ̄-σ x -X ̄+σ x (maximum).Microchemical reactions and spot tests were performed using 10% KOH (K), a sodium hypochlorite solution (C), para-phenylenediamine (PD) and short wave UV 254 light according to Orange et al. (2010).Secondary lichen compounds were identified by TLC in solvents A and B. Calcium oxalate crystals were identified by applying 25% sulfuric acid to squash preparations of thallus and/or ascomata.
Type specimens and non-type material of corticolous Arthonia species described from or mentioned to occur in Africa were studied.The original descriptions of all Arthonia species occurring in tropical Africa were consulted.The following types of (sub)tropical corticolous species of Arthonia which according to the protologues have ascospores with at least one enlarged apical cell and between two and five septa were requested on loan and examined to ensure that no older names were available for the new species (

Molecular techniques
Well-preserved and freshly collected specimens lacking any visible symptoms of fungal infection were used for DNA isolation.Hand-made sections of ascomata or thallus were used for direct PCR as described in Ertz et al. (2014).The lichen material was washed with a 1% KOH solution or acetone, and then rinsed with water to remove remnants of pigments.The material was placed directly in microtubes with 20 µl H 2 O. Amplification reactions were prepared for a 50 µl final volume containing 5 µl 10× DreamTaq Buffer (Thermo Fisher Scientific, Waltham, MA), 1.25 µl of each of the 20 µM primers, 5 µl of 2.5 mg ml -1 bovin serum albumin (Thermo Fisher Scientific, Waltham, MA), 4µl of 2.5mM each dNTPs (Thermo Fisher Scientific, Waltham, MA), 1.25 U DreamTaq DNA polymerase (Thermo Fisher Scientific, Waltham, MA) and the tiny fragments of lichen material.A targeted fragment of about 0.8 kb of the mtSSU rDNA was amplified using primers mrSSU1 and mrSSU3R (Zoller et al. 1999).
A fragment of about 1 kb of the RPB2 protein-coding gene was amplified using primers fRPB2-7cF and fRPB2-11aR (Liu et al. 1999).The yield of the PCR reactions was verified by running the products on a 1% agarose gel using ethidium bromide.Both strands were sequenced by Macrogen® using amplification primers.A BLAST search in GenBank was performed for a preliminary taxonomic assignment of the sequences.They were assembled and edited with Geneious ver.5.1.7(Kearse et al. 2012).

Taxon selection and phylogenetic analyses
Twenty-three new sequences were obtained for this study and 76 additional sequences were retrieved from GenBank (table 1).For the phylogenetic analyses a set of 49 OTUs was used, consisting of taxa representing all major clades currently accepted in the Arthoniaceae except for the more distantly related Bryostigma clade (Frisch et al. 2014a) and for which the mtSSU and the RPB2 were available (table 1).Arthothelium norvegicum Coppins & Tønsberg was chosen as outgroup species.One mtSSU sequence of Synarthonia inconspicua (= S. bicolor) from the USA (Common 10048, hb Common) was not used in the final phylogenetic analysis since the RPB2 sequence was not available for the specimen.Morphologically, this specimen fits well with other material Van den Broeck et al., Phylogenetic position of Synarthonia of S. inconspicua and it was placed within S. inconspicua in a preliminary phylogenetic analysis (results not shown).
To examine topological incongruence among data sets, Bayesian and maximum likelihood (ML) analyses were carried out on each of the single-locus data sets.We used Mr-Bayes ver.3.2.6 (Huelsenbeck & Ronquist 2001, Ronquist & Huelsenbeck 2003), and RAxML ver.7.2.7 (Stamatakis 2006) with 1000 replicates of ML bootstrapping (ML BS) under the GTRGAMMA model of sequence evolution.In both cases, analyses were run on the CIPRES Web Portal (Miller et al. 2010).All topological bipartitions were compared for the two loci.A conflict was assumed to be significant when differing topologies for the same set of taxa (one being monophyletic and the other being non-monophyletic) were each supported with PP values ≥ 0.95 and/or bootstrap values ≥ 70 (Mason-Gamer & Kellogg 1996).Based on this criterion, one conflict was detected regarding the sistergroup relationship of Synarthonia with either Coniocarpon or Reich lingia, see discussion section below.As this conflict had no impact on the monophyly of Synarthonia or our general conclusions on this genus, the mtSSU and RPB2 data sets were concatenated.
The combined two-locus data set of 49 samples consisted of 1503 unambiguously aligned sites, 639 for mtSSU and 864 for RPB2.
Phylogenetic relationship and confidence were inferred for the concatenated two-locus data set using Bayesian inference and maximum likelihood (ML) as optimization criteria.For the Bayesian analyses, best-fit evolutionary models for each partition were estimated using the Akaike Information Criterion (AIC) as implemented in jModelTest2 (Darriba et al. 2012).The TVM+I+G model was selected for the mtSSU data set as well as for the RPB2/2 nd position, while the GTR+I+G model was selected for the RPB2/1 st and RPB2/3 rd positions.
Two Bayesian MCMC runs were executed in parallel, each using four independent chains and 120 million generations, sampling trees every 1000 th generation.TRACER ver.1.6.0(Rambaut et al. 2013) was used to ensure that convergence was reached by plotting the log-likelihood values of the sample points against generation time.Convergence between runs was also verified using PSRF (Potential Scale Reduction Factor), confirming that values for all parameters were equal to 1.000.A tree was generated from 180002 postburnin trees out of 240002 trees for each MCMC runs using the sumt option of MrBayes.Posterior probabilities (PP) were determined by calculating majority-rule consensus trees.For the ML analyses, RAxML was used under a GTRGAMMA model of molecular evolution.Bootstrap support (ML BS) was obtained from 1000 replicates of ML bootstrapping con-ducted with the same settings and program.Internodes with bootstrap proportions ≥70 and Bayesian posterior probabilities ≥0.95 were considered strongly supported (Alfaro et al. 2003, Lutzoni et al. 2004).Phylogenetic trees were visualized using FigTree ver. 1. 3.1 (Rambaut 2012).

Phylogenetic analysis
The Bayesian tree obtained from the combined two-locus analysis of 49 OTUs is shown in fig. 1.The main well-supported lineages of Arthoniaceae are in accordance with the results obtained by Frisch et al. (2014a).The genus Synarthonia is placed in a well-supported lineage (ML BS = 99 and PP = 1) with the genus Coniocarpon and the Reichlingia group, both also being well-supported monophyletic groups (ML BS = 99-100 and PP = 1) (fig.1).
The relationships between the species of Synarthonia are usually well supported (fig.1).Synarthonia albopruinosa, S. inconspicua, S. muriformis and S. pilosella are closely related (ML BS = 98 and PP = 1).These four species are characterized by white pruinose ascomata which react PD+ yellow to orange.Synarthonia aurantiacopruinosa, S. fuscata and S. ochracea form the sister clade to the core group of Synarthonia, this sister relationship being strongly supported (ML BS = 86 and PP = 0.99).These three species have small ascomata lacking white pruina (two having an orange pruina and one being epruinose) and predominantly 3-septate ascospores.Synarthonia josephiana is the most distantly related species, characterized by black epruinose ascomata and 4-septate ascospores.
Independent Bayesian analysis of the mtSSU and RPB2 alignments for the 49 OTUs revealed a phylogenetic conflict between the nuclear and the mitochondrial gene.Based on the mtSSU, Reichlingia (including Arthonia sp.9090 and A. anglica) forms a poorly supported sister group to Coniocarpon (ML BS = 69 and PP = 0.95; figs not shown), while Synarthonia forms a well-supported sister group to the Coniocarpon-Reichlingia clade (ML BS = 93 and PP = 1; figs not shown).
In the phylogenetic tree based on the RPB2, Synarthonia is the well-supported (ML BS = 95 and PP = 1) sister group to Reichlingia, while Coniocarpon is the well-supported sister taxon to the Reichlingia-Synarthonia clade (ML BS = 90 and PP = 1; figs not shown).This phylogenetic conflict between the nuclear and the mitochondrial genes is difficult to explain.It does not seem to be due to our delimitation of excluded ambiguous regions in mtSSU because the conflict persisted with different analyses performed using a narrow or large concept of excluded ambiguous regions in this alignment.Phylogenetic conflicts among closely related and recently diverged species have been reported as a signature of hybridization (Mallet 2005).However, we do not think that this might be responsible for the different sister relationships observed for the genera Coniocarpon, Reichlingia and Synarthonia.Whatever the cause of this conflict, both genes recover Synarthonia as a strongly supported monophyletic genus (ML BS = 95 and PP = 1) closely related to but distinct from Coniocarpon and Reichlingia.Thallus corticolous, rarely absent when young or throughout the life cycle (non-lichenized lichenicolous fungus), crustose, endophloeodal to epiphloeodal, whitish to greenish-grey to green, with or without white striae or spots, continuous to cracked, smooth to verrucose or farinose, sorediate or esorediate, ecorticate; thallus hyphae hyaline.Prothallus not observed, or forming a black to brown compact line in contact with other lichens, sometimes fibrous-like (S. psoromica and S. stigmatidialis) or rhizomorph-like (S. sikkimensis).Photobiont trentepohlioid, in short chains or single-celled, the cells globose to ellipsoid, absent in the non-lichenized lichenicolous species.Ascomata solitary or forming irregular clusters in most of the species, immersed to slightly elevated above thallus level to ± sessile; disc white, greyish or orange pruinose (brown to orange when pruina removed), light brown and almost translucent or blackish-brown with remnants of thallus.Excipulum hyaline to pale brownish to straw-coloured, composed of brown pigmented or hyaline hyphae, non-carbonized.Epihymenium pale brownish, formed by branched and anastomosing brown-walled (K+ olivaceous or K-) or hyaline (K-), 1.3-2.3µm wide paraphysoids with tips thickened or not, inspersed with hyaline, red-brown to orange granular crystals.Hymenium hyaline, not inspersed or rarely inspersed with hyaline or orange granular crystals, I+ directly red, I+ blue rapidly turning into red or I+ persistently blue, K/I+ blue.Paraphysoids hyaline, branched and anastomosing, ± parallel between the asci and forming a dense or loose mesh around the asci.Hypothecium hyaline, yellowish or brownish.Asci broadly clavate, obovoid to ellipsoid or (sub-)globose, 8-spored, with or without K/ I+ blue ring like structures in the tholus, occasionally with a distinct or indistinct ocular chamber.Ascospores persistently hyaline, or brownish and ornamented with small brown (K+ olivaceous) warts at late maturity, ellipsoid to oblong-ovoid, transversely septate with an enlarged apical cell or muriform, with or without a gelatinous sheath.Pycnidia black, walls brown.Conidia hyaline, bacilliform, non-septate, straight to slightly curved.Chemistry -Parietin, evernic acid, psoromic acid, unidentified xanthones, unknown secondary compounds or secondary compounds absent.Calcium oxalate crystals absent in most of the species (occasionally present in the ascomata of S. muriformis).Distribution and ecology -Lichenized species of Synarthonia occur mainly in the tropics, more rarely in temperate regions, and are corticolous with a preference for smooth barked trees and rather exposed conditions (branches, free standing trees).The (facultatively) lichenicolous species of the S. ochracea complex appear to be restricted to corticolous species of Graphis early in their development, while S. rimeliicola is living on species of Parmeliaceae.Notes -The genus Synarthonia is characterized by a combination of the following characters: ascomata often aggregated in clusters, ascospores transversely septate with an enlarged apical cell or muriform, and a secondary chemistry including evernic acid, psoromic acid, xanthones, unknown secondary compounds, or compounds absent.
According to Joseph & Sinha (2015) the genus Synarthonia is characterized by solitary ascomata becoming mono-to pluri-carpocentral synascomata embedded in a slightly elevated to immersed pseudostroma, with a thin white thalline margin.Cross sections of ascomata in some of our specimens showed two or three loculi of hymenium separated by thin interhymenial strands suggesting synascomata (fig.2C).However, these interhymenial strands may also be caused by ascoma branching or grouped ascomata and cannot be differentiated from excipular hyphae.Moreover, this character is not always easy to observe.Therefore, we decided not to use the terminology of Joseph & Sinha (2015) pending further studies on the ascoma ontogeny of Synarthonia.
Notes -The type specimens of Synarthonia bicolor Müll.Arg., Arthonia inconspicua Stirt., A. subcaesia C.W.Dodge and A. translucens Stirt.agree well in the morphology of thallus, ascomata and ascospores.S. inconspicua is the correct name due to its nomenclatural priority (oldest name).
Types specimens of Arthonia inconspicua and A. translucens bear labels added by Patwardhan & Makhija in 1977 indicating "lectotype", but to our knowledge the lectotypifications have not been effectively published.Therefore, lectotypes are designated here.The examined Deighton type specimen of Arthonia subcaesia contains two twigs, each with a different species of Arthoniaceae.On one of the twigs a specimen of Synarthonia is present, and on the other twig a specimen of Coniocarpon.The description by Dodge fits best the species of Synarthonia (disc densely white pruinose and ascospores of 18.0-22.0× 5.5-6.0 µm), which is therefore selected here as lectotype.The species of Coniocarpon is characterized by purplish spots on the ascomata, a character not mentioned by Dodge, and larger ascospores of 23.0-23.5 × 8.0-8.5 µm.
Etymology -The epithet muriformis refers to the muriform ascospores.Van den Broeck et al., Phylogenetic position of Synarthonia Notes -In most of the examined ascomata no asci or ascospores could be found.Synarthonia muriformis is most similar to S. sarcographoides in having muriform ascospores and heavily white pruinose ascomata, but S. sarcographoides differs by larger ascomata (up to 2 mm), smaller ascospores (20-22 µm long) and in lacking psoromic and evernic acids (thallus and ascomata PD-).
A survey of all protologues and the study of all types of the African Arthothelium species failed to identify any species with the same characteristics as S. muriformis.Van den Broeck, Eb.Fisch., Killmann & Ertz, sp.nov.

New combinations in Synarthonia
We here place some species of Arthonia with an orange pruina on the ascomata (K+ purplish) and transversely septate ascospores with enlarged apical cell in Synarthonia, even though molecular data are missing for these species.We did not include the orange pruinose A. leucographella Müll.Arg.since this species, according to the protologue, is characterized by elliptic-fusiform, 7-9-septate ascospores with narrowed obtuse ends and larger median cells (Willey 1890).We also did not include A. rubiginella Nyl.since this species has ascospores with two larger apical cells (Nylander 1900).Two of the newly combined species are starting growth as a non-lichenized lichenicolous fungus on species of Graphis, sometimes subsequently developing an independent thallus, while two others are presistently non-lichenized lichenicolous fungi on species of Graphis.Morphologically, these species are highly similar in sharing orange pruinose/pigmented ascomata with small (< 20 µm long), (2-)3(-4)-septate hyaline ascospores becoming brown and ornamented with small Van den Broeck et al., Phylogenetic position of Synarthonia purple to red and partly dissolving, without amorphous pigment.Hymenium 34-53 µm tall, orange, not inspersed, I+ blue, K/I+ blue.Paraphysoids 0.7-0.9µm wide, the tips with hyaline walls.Hypothecium orange brown, 20-25 µm thick, I+ blue, K/I+ blue.Asci broadly clavate to subglobose, 36-50 × 14-28 µm (N = 5), stipitate; a K/I blue ring like structure not observed; the asci occasionally filled with amorphous orange pigment.Ascospores 15.0-19.0× 5.0-6.5 µm (N = 15), hyaline becoming brown with ornamentation of brown warts at late maturity, with enlarged apical cell, oblong-ovoid; lumina of apical cell 7.0-7.2× 3.9-4.2µm, lumina other cells 1.0-1.5 × 3.1-3.4µm, (3-)4-septate; gelatinous sheath not observed.Pycnidia not observed.Chemistry -Calcium oxalate crystals in ascomata and thallus not observed.Thallus UV+ pale orange, ascomata UV+ dark orange.TLC and spot tests not performed (type specimen).Distribution and ecology -Synarthonia lopingensis appears to start as a juvenile parasite on the thallus of Graphis spp. in E Asia (China, Japan; Frisch et al. 2018) before developing its own thallus or it might be a facultatively lichenicolous fungus.Notes -Synarthonia lopingensis belongs to the S. ochracea complex based on the orange pruinose ascomata, the ascospores type and the (facultatively) lichenicolous growth on species of Graphis.The type specimen consists of two pieces of bark.Synarthonia lopingensis is found only on one of the pieces while another species of Arthonia s. lat. is present on both.The latter differs from S. lopingensis by black ascomata with a purplish tinge, a purplish pigment in the ascomata, and 3-septate ascospores with an enlarged apical cell becoming brown at late maturity, 14.5-17.0× 5.0-6.5 µm.Calcium oxalate crystals could not be observed for this species, which probably belongs to Coniocarpon.We lectotypify S. lopingensis based on the protologue on the specimen with substellate ochraceous ascomata as indicated by an arrow on the voucher.
Synarthonia lopingensis is morphologically similar in most aspects to S. hodgesii, S. ochracea and S. ochrodes but the ascomata are aggregated in irregular star-shaped clusters.
A recently reported specimen from Vietnam, published under the name Arthonia elegans (Joshi et al. 2018), is similar to S. lopingensis.It is lichenized and characterized by marginally reddish-brown pruinose ascomata aggregated in irregular star-shaped clusters.But the hyaline ascospores, which are not becoming brown at late maturity, are much smaller (10-12 µm long) with more septa (4)(5).Additional collections are required to establish if these differences merit formal taxonomic recognition.(Dufour) Van den Broeck & Ertz, comb.nov.
A species of the Graphis scripta species complex is present on most of the examinated specimens of S. ochracea.thonia and the Graphis suggesting that S. ochracea starts as a lichenicolous fungus on Graphis before developing its own thallus.However, it is sometimes difficult to establish if S. ochracea is clearly parasitic or just marginally confluent with or overgrowing the Graphis species.On specimens from Saint-Sever (G, barcodes G00295952 and G00295953) no species of Graphis could be observed.More studies are necessary to understand the biology of S. ochracea and to investigate if more than one species is involved, in particular with respect to the possibly lichenicolous versus the lichenized specimens.
Synarthonia ochracea is part of a complex of closely related species whose biology and circumscription are still in need of further studies.It is morphologically similar in most aspects to S. lopingensis and S. ochrodes, but the ascomata are aggregated in irregular lobed clusters.In S. hodgesii, the ascomata are not aggregated in clusters and evenly orange, with a non-granular pigmentation.
Chemistry -Thallus UV+ orange.Calcium oxalate absent in ascomata and thallus.TLC and spot tests not performed (type specimen).Distribution and ecology -Synarthonia ochrodes has been described from Cuba.The specimen reported from Thailand by Vainio (1909) does not fit our concept of S. ochrodes since the hymenium of this species reacts I+ blue rapidly turning into red (persistently blue in S. ochrodes).Notes -The ascomata of the type of S. ochrodes are strongly orange pruinose, a character not mentioned in the protologue (Willey 1890).They grow on the thallus of a species of Gra-phis without any visible own thallus.This suggests that S. ochrodes is a lichenicolous fungus.

Synarthonia rimeliicola
The host of the type specimen is in poor condition and was published as Rimelia reticulata (Aptroot et al. 1997).However, a re-examination of the isotype in hb Diederich revealed the presence of ciliate isidia, the absence of soralia, a K+ yellow-orange cortex and a PD+ orange medulla.These characters relate to Parmotrema crinitum, a species that had been reported from the type locality by Louwhoff & Elix (1999).
A description and illustrations can be found in the protologue.Synarthonia rimeliicola is morphologically similar to other species of Synarthonia by whitish pruinose, PD+ yellow ascomata and ascospores with an enlarged apical cell.

Notes on the related genus Coniocarpon
Coniocarpon differs from Synarthonia mainly in its secondary chemistry including anthraquinones and isofuranonaphtoquinones (Yamamoto et al. 2002, Frisch et al. 2014a).Redpurple pigments, K+ red or purple and partly to completely dissolving and calcium oxalate crystals are often present in the ascomata of species of Coniocarpon.
Notes -The typification of the name Spiloma elegans Ach.requires some discussion.In the protologue, Acharius (1810) noted that the original material of Schleicher, on which the name is based, consisted of a species with red coloured ascomata ("apotheciis punctiformibus substellatisque coccineis").The colour drawing in the protologue shows two colours, red and a paler central part for some ascomata.Thus, it is clear from the protologue that the name applies to a taxon with red (or reddish pruinose) ascomata.A specimen of S. elegans with the annotation 'Helvetia' is preserved in H, labelled as 'syntype', the only specimen of S. elegans in H (according to the curator L. Myllys).This specimen has ochraceous ascomata and represents Arthonia ochracea Dufour, described in 1818.That species was considered a variety of Coniocarpon cinnabarinum by various authors (e.g.Nylander 1853, 1856, Zahlbruckner 1923-1924) or placed in synonymy with A. elegans (e.g.Schaerer 1823, Almquist 1880).However, this synonymysation probably was not based on the original material of A. elegans as there is no reference to the material of Schleicher Pl.Cr.Helv.Centur.5 n 54 in the cited literature.Another syntype specimen in S bears the number 5 n 54 corresponding to Schleicher's Pl.Cr.Helv.and is labelled "Arthonia elegans".This is the name given by Schleicher in his exsiccate, cited as synonym of Spiloma elegans in the original description by Acharius.This specimen bears the number (5 n 54) cited in the protologue by Acharius and the red ascomata have the colour ("coccinea") described in the protologue.For this reason, we lectotypify the name Spiloma elegans on the syntype in S. The selected lectotype is characterized by ascomata having an exposed hymenial disc covered by a pale greyish pruina, and margins covered by an orange-reddish pruina; asci 45 × 24 µm, 8-spored; ascospores 14.0-18.0× 6.0-7.0 µm (N = 11, from two different ascomata), hyaline becoming dark brown at late maturity, oblong-ovoid, with enlarged apical cell, 3-4-septate.Therefore, according to the ascospores, it fits with the current concept of Coniocarpon fallax (Ach.)Grube.As a consequence, Spiloma elegans becomes a synonym of C. fallax since this is the older name.A request to other herbaria (BM, BM, BPI, CAN, E, G, GOET, H, KIEL, L, LD, M, PC, W, WRSL) to obtain additional material of Schleicher Pl.Cr.Helv.Centur.5 n 54 of Spiloma elegans to find out if this number of the exsiccate is homogeneous, was not successful.In selecting the type specimen from S with the number "5 n 54" of Schleicher Pl.Cr.Helv.and labelled "Arthonia elegans" as lectotype, we follow recommendation 9A.2. of the Botanical Code (Mcneill et al. 2012) that in choosing a lectotype all aspects of the protologue should be considered as a basic guide.
Coniocarpon tuckermanianum (Willey)  Notes -This species is characterized by a white, continuous thallus with numerous, semi-immersed, reddish brown to black ascomata, occasionally with some white pruina.The ascospores are (3-)4-5(-7)-septate, 17.0-23.5× 6.0-8.0 µm and have an enlarged apical cell.Internally, a purplish pigment (K+ dissolving) is present at the perihymenial margins.Abundant calcium oxalate crystals have been observed in the ascomata.This species is a typical member of Coniocarpon.It differs from the other species of this genus by the absence of a reddish pruina, reddish brown to black ascomata and up to 7-septate ascospores.
Contrary to the key and description in Sparrius (2004), the ascospores of S. elegans are sometimes 4-septate as in S. extenuatum (Nyl.)Sparrius, but the latter species clearly differs by the presence of protocetraric acid.

DISCUSSION
Considerable progress has recently been made in the phylogeny of the Arthoniales, but much remains to be done in the family Arthoniaceae, where most species of the large and heterogeneous genus Arthonia still cannot be reallocated to other genera due to the lack of molecular data for several genera.Our study provides a further step in this process by resolving the phylogenetic placement of the genus Synarthonia, thanks to the sequencing of its type species and a few other related species.
Synarthonia is quite heterogeneous in morphology, particularly in the structure of the ascomata.The core group of Synarthonia is represented by the type species S. inconspicua and other species having notably white pruinose, PD+ yellow to orange ascomata that are often clustered, viz.S. albopruinosa, S. muriformis and S. pilosella.This group is phylogenetically well supported (fig.1).S. astroidestera obviously also belongs to the core group of Synarthonia as judged by its morphology and chemistry, despite the species was not included in the phylogeny.The sister clade to the core group contains two orange pruinose species (S. aurantiacopruinosa and S. ochracea) and the epruinose S. fuscata (fig.1).The more distantly related S. josephiana has also epruinose ascomata, but they are covered with remnants of thallus.
At present it is not fully clear which are the main morphological characteristics that distinguish Synarthonia from other genera in the family Arthoniaceae.The presence or absence of clustered ascomata is not sufficient because in the phylogenetic tree, species clearly lacking such ascomata are included in the genus (e.g. S. fuscata, fig.3F).Already S. sarcographoides was assigned only with hesitation to the genus as the organisation of several ascomata in a pseudostroma makes it difficult to ascertain whether or not the pale marginal areas of the ascomata should be seen as ascomatal tissue (Menezes et al. 2013).Other characteristics, such as the transversely septate ascospores with enlarged apical cell can also be found in genetically distantly related species, such as Arthonia ilicina (Frisch et al. 2014a).Arthonia ilicina shares further characteristics with some species of Synarthonia, such as brown-walled (K+ olivaceous) paraphysoids in the epihymenium and ascospores becoming brown and warted at late maturity.
Our phylogenetic analysis clearly demonstrates that the morphologically and phylogenetically closely related genus Reichlingia is not a synonym of Synarthonia as was suggested by Joseph & Sinha (2015).Fertile species of Reichlingia are characterized by adnate, pruinose and often elongate to stellate-branched ascomata; epithecium greyish by inspersion with pale granular crystals or dark brown; hymenium hyaline, clear or sparsely inspersed with pale granular crystals, I+ blue or pale yellowish brown; a well-developed hyaline to pale brownish hypothecium; tips of paraphysoids with or without dark brown pigmented walls; oblong-ovoid, hyaline, transversely septate with enlarged apical cell or submuriform ascospores that may or may not get brownish with dark brown warty ornamentation at late maturity (Diederich & Scheidegger 1996).Reichlingia differs from Synarthonia by a compact-felty to byssoid-granular thallus, ascomata with individual hymenia separated by deep but often incomplete fissures and a secondary chemistry including 2'-O-methylperlatolic acid and perlatolic acid (Diederich & Scheidegger 1996, Frisch et al. 2014a).An unidentified xanthone has been found in R. virginea (Müll.Arg.)Frisch, but that species has not been sequenced yet (Frisch et al. 2014b).Synarthonia is also closely related to Coniocarpon in our phylogenetic tree (fig.1), and the ascomata and thallus morphology of Synarthonia shows many similarities with Coniocarpon.The species of both genera are characterized by adnate, often pruinose and rounded, elongated to stellate to lobbed ascomata with a well-developed hyaline, brownish to yellowish hypothecium, and oblong-ovoid, hyaline, transversely septate with an enlarged apical cell ascospores that may or may not get brownish with dark brown warty ornamentation in the epispore at late maturity.Coniocarpon differs from Reichlingia and Synarthonia mainly in its secondary chemistry including anthraquinones and isofuranonaphtoquinones (Yamamoto et al. 2002;Frisch et al. 2014a).Red-purple pigments, K+ red or purple, partly or completely dissolving, and calcium oxalate crystals are often present in the ascomata of species of Coniocarpon.White pruinose ascomata can be observed in some species of the genus Coniocarpon but, to our observations, in such ascomata purplish pigments (K+ dissolving) are always discernible.The genus Synarthothelium Sparrius differs from Synarthonia mainly by muriform ascospores that are > 40 µm long and an Arthothelium type of asci (Sparrius 2009).
The current study is a further step in our understanding of the phylogenetic relationship of the taxa within Arthoniaceae, but much remains to be done since a lot of species currently placed in Arthonia s. lat.have not been sequenced yet.

Figure 1 -
Figure 1 -Phylogenetic relationships among a selected group of Arthoniaceae resulting from a Bayesian analysis based on a data set of 49 samples of mtSSU and RPB2 sequences.Arthothelium norvegicum was chosen as outgroup.MrBayes posterior probabilities are shown above branches, and RAxML bootstrap values are shown below branches.Thicker lines highlight internodes considered strongly supported by both analyses.Synarthonia is indicated in bold and highlighted with a blue coloured box.