683 MycoKeys MycoKeys 114: 277-298 (2025) DOI: 10.3897/mycokeys.114.146031 Research Article Lijiangomyces laojunensis gen. et sp. nov. (Mytilinidiaceae), and Sclerococcum stictae (Dactylosporaceae), a new lichenicolous species from Yunnan, China Qingfeng Meng'?2®, Paul Diederich*®, Vinodhini Thiyagaraja°®, Damien Ertz®’7®, Xinyu Wang>®®, Natsaran Saichana®®, Kevin D. Hyde?2©, Ruvishika S. Jayawardena?2°®, Shaobin Ful?® oO AN DT oO FP WO YN — School of Public Health, Zunyi Medical University, Zunyi City, Guizhou Province 563000, China Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand Musée national d'histoire naturelle, 25 rue Munster, L - 2160 Luxembourg, Luxembourg Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China Meise Botanic Garden, Research Department, Nieuwelaan 38, 1860 Meise, Belgium Fédération Wallonie-Bruxelles, Service Général de I'Enseignement Supérieur et de la Recherche Scientifique, rue A. Lavallée 1, 1080 Bruxelles, Belgium Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea 10 School of Pharmacy, Zunyi Medical University, Zunyi City, Guizhou Province 563000, China Corresponding authors: Ruvishika S. Jayawardena (ruvishika.jay@mfu.ac.th); Shaobin Fu (fushb@126.com) OPEN Qaceess This article is part of: Exploring the Hidden Fungal Diversity: Biodiversity, Taxonomy, and Phylogeny of Saprobic Fungi Edited by Samantha C. Karunarathna, Danushka Sandaruwan Tennakoon, Ajay Kumar Gautam Academic editor: Samantha C. Karunarathna Received: 6 January 2025 Accepted: 2 February 2025 Published: 4 March 2025 Copyright: © Qingfeng Meng et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Abstract Lijiangomyces laojunensis gen. et sp. nov. and Sclerococcum stictae sp. nov. are reported from China and identified through DNA sequence analyses (LSU, ITS, and tefl-a) and morphological characteristics. Phylogenetic analysis showed that L. laojunensis forms a distinct lineage within Mytilinidiaceae, closely related to the Mytilinidion subclade, leading to the establishment of a new genus within this fam- ily. This saprotrophic species grows on the bark of Abies fabri, often surrounded by the thallus of Pertusaria species. Lijiangomyces laojunensis is characterized by broadly open, black hysterothecia, clavate asci, and uniseriate, hyaline muriform as- cospores. Sclerococcum stictae, a new lichenicolous species, forms a sister clade relationship to a lichenicolous fungus, S. ricasoliae. It was found on the thallus of Sticta, and is characterized by black apothecia, elongate, cylindrical asci, and brown, elliptical, and 1-septate ascospores. Descriptions, illustrations, and phylogenetic analysis results of the new taxa are provided. Key words: 2 new taxa, lichen, morphology, phylogeny, saprobe, taxonomy Introduction Mytilinidiaceae belongs to Mytilinidiales, Dothideomycetes (Hyde et al. 2024), and was introduced by Kirschstein (1924) to accommodate four genera that were originally classified under Hysteriaceae. Boehm et al. (2009a) introduced Mytilinidiales based on multigene phylogenetic analysis to accommodate Mytilinidiaceae. Pem et al. (2024) included eight genera poe: Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Citation: Meng Q, Diederich P Thiyagaraja V, Ertz D, Wang X, Saichana N, Hyde KD, S. Jayawardena R, Fu S (2025) Lijiangomyces laojunensis gen. et sp. nov. (Mytilinidiaceae), and Sclerococcum stictae (Dactylosporaceae), a new lichenicolous species from Yunnan, China. MycoKeys 114: 277-298. https://doi.org/10.3897/ mycokeys.114.146031 within Mytilinidiaceae: Actidium, Lophium, Mytilinidion, Ostreola, Peyronelia, Pseudocamaropycnis, Quasiconcha and Zoggium. Hyde et al. (2024) added three more genera: Bullatosporium, Camaroglobulus and Halokirschsteinio- thelia, increasing the total to eleven genera within this family. Members of Mytilinidiaceae are distinguished by their globose or obovoid pseudothecia which are typically oyster- or hatchet-shaped with a longitudinal keel and crested apex. They feature bitunicate asci containing eight ascospores that are arranged uniseriately, biseriately, or in aggregated clusters. The asco- spores are hyaline to brown, exhibiting diverse morphologies such as scole- cospores, didymospores, phragmospores, or dictyospores, and with bipolar symmetry (Boehm et al. 2009a). Mytilinidion was established to accommodate the type species M. aggre- gatum. This genus is characterized by globoid to obovoid, erect, conchate, or dolabrate ascomata, and a thin-walled and peridium, bitunicate, 8-spored asci. The ascospores are hyaline to brown and transversely 3-5(—7)-septate (Boehm et al. 2009b; Jayasiri et al. 2018). Ostreola was introduced to accom- modate two species, O. consociate and O. sessilis, characterized by conchiform to hatchet-shaped hysterothecia with a longitudinal slit that opens narrowly. The asci are cylindrical, containing eight uniseriate, brown and muriform as- cospores (Darker 1963). Ostreola shares similarities with Mytilinidion and Lo- phium in the ascomatal morphology but is distinguished by the presence of muriform ascospores. Lumbsch and Huhndorf (2007) placed Ostreola within Mytilinidiaceae. The members of Mytilinidion are primarily saprobic and plant pathogens, while Ostreola species are primarily saprobic. Sclerococcum belongs to Dactylosporaceae, Sclerococcales, Eurotiomy- cetes (Hyde et al. 2024), and was described by Fries (1819, 1825) to accom- modate the parasitic hyphomycetous fungus S. sphaerale, which was previ- ously classified as Spiloma sphaerale. Phylogenetic analysis by Diederich et al. (2013) revealed that S. sphaerale clusters with two species of Dactylo- spora. In a subsequent study incorporating expanded molecular data, Die- derich et al. (2018) proposed adopting the family name Dactylosporaceae, with Sclerococcaceae as its synonym. They further recommended retain- ing Sclerococcum as the valid genus name and synonymizing Dactylospo- ra under it, as Sclerococcum has nomenclatural priority over Dactylospora. Consequently, 46 Dactylospora species were transferred to Sclerococcum (Diederich et al. 2018). Dactylosporaceae comprises six genera: Cylindro- conidiis, Fusichalara, Gamsomyces, Pseudosclerococcum, Rhopalophora and Sclerococcum (Hyde et al. 2024). During a survey of microfungi in Yunnan Province (Thiyagaraja et al. 2024), two unidentified fungal specimens were collected. The first spec- imen was found on the bark of Abies fabri, and was often surrounded by the thallus of Pertusaria species while the second was observed growing on the thallus of a foliose lichen belonging to Sticta. Phylogenetic analyses and morphological comparison reveal that the first specimen represents a novel genus closely related to Mytilinidion within Mytilinidiaceae. The sec- ond specimen is proposed as a new lichenicolous species within the genus Sclerococcum based on morpho-molecular analyses. MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 278 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Materials and methods Sample collection and morphological examination The specimens were collected from Yunnan Province, China and the im- portant collection information was noted (Rathnayaka et al. 2024). Mac- ro-morphological characteristics were observed using a stereomicroscope (Olympus ZX-16) and photographed with a fitted digital camera (Olympus SC180). The ascomata were sliced, temporarily mounted, and observed un- der a compound microscope (Nikon Y-TV55), with images captured using a fitted digital camera (Nikon DS-Ri2). Distilled water was used as a mounting slide solution and 10% potassium hydroxide (K) and Lugol's iodine solution (I) were used to stain and examine the hymenium. Photographic plates were assembled using Adobe Photoshop CC 2019 software (Adobe Systems, USA). Measurements were conducted using Image Framework software (Tarosoft, Version 0.9.7). The length, width, and length/width ratio (I/w) of asci and ascospores are provided (where n = 10) as: (min—) [X-SD]-[X+SD] (—max), where “min” and “max” represent the extreme observed values, X is the arithmetic mean, and SD is the standard deviation. The number of measurements (n) is indicated. Unless otherwise specified, measurements were taken from water mounts, and procedures followed those specified by Senanayake et al. (2020). The holotype specimens are deposited in the Li- chen Herbarium of Kunming Institute of Botany (KUN-L), Chinese Academy of Science, Yunnan, China. DNA extraction, PCR amplification, and sequencing Apothecia were carefully removed with a razor blade under a dissecting mi- croscope, and the lichen thallus was thoroughly cleaned. The sample was then transferred to a 200 uL centrifuge tube. Total genomic DNA was ex- tracted using a Forensic DNA Kit (Omega Bio-Tek, Norcross, Georgia), fol- lowing the manufacturer's instructions. The primer pairs ITS1f/ITS4, LROR/ LR5, 983F/2218R and mrSSU1/mrSSU3R were used respectively, to amplify the internal transcribed spacer region of rDNA (ITS), the 28S large-subunit of rDNA (LSU), the translation elongation factor 1-alpha (tef1-a), and the mitochondrial small subunit ribosomal RNA gene (mtSSU) (Vilgalys and Hester 1990; White et al. 1990; Gardes and Bruns 1993; Zoller et al. 1999; Rehner and Buckley 2005). The polymerase chain reaction (PCR) was performed using a Mastercycler (Bio-RAD T-100) in a 25-uL reaction volume consisting of 12.5 uL of 2 x Mix (Solarbio, dNTPs Mix), 9.5 uL of double-distilled water (ddH,0), 1.0 pL of each primer (10 mM), and 1.0 uL of the DNA template. The PCR conditions were as follows: an initial denaturation at 95 °C for 3 minutes, followed by 35 cycles of denaturation at 95 °C for 45 seconds, annealing at 53 °C for ITS, LSU, and mtS- SU or at 58 °C for tef1-a, for 90 seconds, and elongation at 72 °C for 1 minute. A final extension was performed at 72 °C for 10 minutes, and the reaction was then held at 4 °C indefinitely. PCR products were sequenced by Shanghai San- gon Biotech (Chengdu, Sichuan Province, China). MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 279 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Sequence alignment and phylogenetic analyses The quality of chromatogram sequences was verified using BioEdit Sequence Alignment software (Version 7.0.9.0). Forward and reverse sequences were assembled with ContigExpress software (New York, USA). The newly gener- ated sequences were subjected to BLASTn searches (https://blast.ncbi.nim. nih.gov/Blast.cgi) and deposited in the GenBank database. BLAST analysis of three genes (LSU, ITS, and tef1-a) from specimen KUN-L 88703 indicated that this species might belong to Gloniales, Hysteriales, or Mytilinidiales. To confirm its phylogenetic placement, all available sequence data from these orders were downloaded from GenBank (Table 1). Additionally, representative species from six adjacent orders, viz. Botryosphaeriales, Capnodiales, Do- thideales, Jahnulales, Patellariales, and Pleosporales were included based on references from Boehm et al. (2009b). Two species of Orbilia (Orbiliomycetes, Orbiliales, Orbiliaceae) were selected as the outgroup taxa following Hong- sanan et al. (2020) for phylogenetic analysis. The BLAST analysis of three genes (LSU, ITS, and mtSSU) from the specimen KUN-L 88687 indicated that this species belongs to Sclerococcales. Sequence data for all available taxa within this order were retrieved from GenBank and are listed in Table 2. Two species of Caliciopsis (Coryneliaceae, Coryneliales, Coryneliomycetidae, Eurotiomycetes) were included as the outgroup following Olariaga et al. (2019). Sequence alignment, concatenation, model selection, and format con- version were performed using the OFPT program (Zeng et al. 2023). Each gene region dataset was aligned using the ‘auto’ strategy in MAFFT (Katoh and Standley 2013) and trimmed with the ‘gappyout’ command in TrimAl (Capella-Gutierrez et al. 2009). The best-fit nucleotide substitution models for each dataset were selected using the Bayesian Information Criterion (BIC) from twenty-two common DNA substitution models with rate hetero- geneity, as implemented in ModelFinder (Kalyaanamoorthy et al. 2017). The datasets were then concatenated with partition data for subsequent phylogenetic analyses. Maximum likelihood (ML) analysis was conducted on the IQ-TREE web server applying the ultrafast bootstrap approximation with 1,000 repli- cates (Hoang et al. 2018), and the SH-like approximate likelihood ratio test (SH-aLRT) (Guindon et al. 2010; Nguyen et al. 2015). The consensus tree was summarized using the extended majority rule. For further verification, an additional ML analysis was performed with RAxML-HPC2 on ACCESS (v8.2.12), using the GTRGAMMA model with a rapid bootstrap analysis of 1000 replicates (Miller et al. 2010; Stamatakis 2014). Bayesian inference was carried out using two parallel Metropolis-coupled Markov Chain Monte Carlo (MCMC) runs, each consisting of one ‘cold’ chain and three heated chains, in MrBayes (Ronquist et al. 2012). Trees were sam- pled every 1,000 generations, and the run was terminated when the average standard deviation of split frequencies fell below 0.01. The final tree was sum- marized after discarding the first 25% of samples as burn-in and visualized in FigTree v1.4.4 (Rambaut 2016). The newly identified taxon was registered in Index Fungorum and Faces of Fungi database (Jayasiri et al. 2015). MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 280 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Table 1. Sequences used in phylogenetic analysis of Mytilinidiales and adjacent orders, with specimens or strains information and GenBank accession numbers. Newly obtained sequences are in bold font. “NA” indicates the sequence is unavailable. Species name Aigialus grandis A. mangrovis A. parvus A. rhizophorae Aliquandostipite crystallinus A. khaoyaiensis Ascagilis guttulaspora A. submersa A. thailandensis Botryosphaeria dothidea Brachiosphaera tropicalis Bullatosporium taxicola B. taxicola Capnodium aciculiforme C. alfenasii C. coartatum Cenococcum geophilum C. geophilum Chaetocapnodium insulare C. philippinense C. placitae Conidiocarpus asiaticus C. caucasicus C. fici-septicae C. siamensis Delitschia chaetomioides D. winteri Dothidea insculpta D. sambuci Ericboehmia centramura EF. curtisii E. doimaeensis Fusculina eucalypti Gloniopsis arciformis G. calami G. leucaenae G. percutanea Glonium circumserpens G. circumserpens G. stellatum G. stellatum Glyphium elatum Gordonomyces mucovaginatus Graphyllium caracolinense Guignardia gaultheriae Voucher/strains BCC 20000 BCC 33563 PUFD45 BCC 33572 AFO07 MFLUCC 21-0106 MFLUCC 17-0244 MFLUCC 18-1143 MFLUCC 18-1149 CBS 115476 SS 2523 a21-004; CBS 151403 a21-005; CBS 151402 CBS 892.73 CBS 146151 CPC 17779 CG5 CG54 CBS 146159 MFLUCC 12-0110 CBS 124758 MFLUCC10-0062 GUMH937 MFLUCC 19-0072 SICAUCC 23-0010 DSE871 AFTOL-ID 1599 CBS 225.62 CBS 189.58 DAOM 231303 chuni 70 MFLUCC 12-0808 CBS 198.34 MFLUCC 16-0329 CBS 120083 GKM L166A MFLUCC 15-0739 MFLU 21-0201 FMR 8713 CBS 123342 CBS 123343 ANM 32; A. Miller 32, F CBS 207.34 EB 0365; BPI 892671 CBS 127273 HUEFS 42838 CBS 447.70 MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 GenBank accession numbers ITS NA NA MK028710 NA NA MT864350 NA NR_171970 NR_171969 NA FJ887923 PP516536 PPat6525 NA MN749233 MN749236 KC967409 KC967410 NR_168830 NR_168831 MH863403 NA NA MW063143 OR405901 MW209042 NA NA NA KM272258 NA MH535872 DQ923531 NA NR_164398 OL782134 AM286786 NA NA NA MZ570257 KM220945 NR_157428 NA MH859790 LSU GU479775 GU479776 MK026761 GU479780 EF175652 MT860428 NG_064432 MN888485 MN913693 DQ678051 JN819284 PPS16533 PP516534 GU301847 MN749165 MN749167 NA NA NG_068681 KP744503 MH874920 JN832612 KC833050 MW063206 OR405912 MW209067 DQ6/8077 DQ247802 AY544681 KM272256 MH866967 MH9535894 DQ923531 GU323211 NG_059715 OL782050 LS997561 FJ161208 FJ161200 GQ221887 FJ161179 KM220939 NG_057941 NG_060651 DQ678089 tefl1-a NA GU479840 MN520611 GU479844 NA MT873577 NA NA NA DQ767637 JN819298 PP514386 PP514385 GU349045 MN829346 MN829348 NA NA MN829359 MN829362 MN829363 NA NA NA OR671432 MW238837 DQ677922 DQ471081 DQ497606 KM277819 FJ161093 NA NA NA KX671965 OL875100 LS997569 NA NA GQ221926 FJ161095 KM220933 NA NA NA 281 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Species name Halokirschsteiniothelia maritima H. maritima H. maritima Hysterium angustatum H. pulicare H. rhizophorae Hysterobrevium baoshanense H. constrictum H. rosae Hysterodifractum partisporum Hysterographium didymosporum H. fraxini H. minus Hysteropatella elliptica H. prostii Jahnula appendiculata J. dianchia J. rostrata Lophium arboricola L. arboricola L. arboricola L. mytilinum L. mytilinum L. zalerioides Massaria inquinas M. vomitoria Mytilinidion acicola M. acicola M. andinense M. australe M. californicum M. didymospora M. mytilinellum M. mytilinellum M. resinicola M. rhenanum M. rhenanum M. scolecosporum M. thujarum M. tortile M. tortile Neocamarosporium goegapense N. phragmitis Neomassaria fabacearum N. formosana Oedohysterium insidens O. insidens O. sinense Voucher/strains 3124D CBS 221.60 NWHC 45703-222 KUMCC 21-0213 EB 0238; CBS 123377 MFLUCC 15-0950 MFLUCC 16-2162 KUN-HKAS102101 CBS 149699 HUEFS 42865 MFLUCC 10-0101 CBS 109.43 JCM 2758 AFTOL-ID 1790 CBS 935.97 G.M. 2016-02-20.2 BCC11400 KUMCC 17-0039 MFLU 20-0435 CBS 758.71 FMR 3868 P99; KRAM F-59986 CBS 114111 CBS 269.34 MFLUCC 14-0417 WU 30527 WU 30606 EB 0349; BPI 879794 EB 0379; BPI 879793 EB 0330; CBS 123562 CBS 301.34 EB 0385; BPI 879795 MFLUCC 16-0619 CBS 303.34 EB 0386; BPI 879796 CBS 303.34 CBS 304.34 CBS 135.34 EB 0341; CBS 135.45 CBS 305.34 EB 0268; BPI 879797 CBS 306.34 EB 0377; BPI 879798 CBS 138008 MFLUCC 17-0756 MFLUCC 16-1875 NTUCC 17-007 ANM 1443 A. Miller 1443, F CBS 238.34 EB 0339; BPI 879800 MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 GenBank accession numbers ITS KM272366 NA MK782369 OK482567 NA NR_189349 MZ467049 MN429070 0Q990113 NA NA NA NA NA MT341324 JN819280 KY928456 MT627720 NA KU705825 OR754902 EF596819 OM337540 MF621583 HQ599402 HQ599437 NA NA NA NR_160067 NA NA NA NA MH855535 NA NA MH855536 NA MH855537 NA KJ869163 MG844345 NA NA NA NA NA LSU NA AY849943 NA OK482568 FJ161201 NG_241879 KX772765 MN429073 0Q990064 NG_060652 NG_064526 FJ161171 NG_059814 DQ7/6/657 MT341324 FJ743446 KY928457 MT627657 MH872091 KU705842 OR/54924 EF596819 MH867013 MF621587 HQ599402 HQ599437 GU323209 GU397346 FJ161199 MH867035 GU323208 MH535902 MH867037 GU397347 MH867038 NA GU323207 MH867039 GU323206 MH867040 GU323205 KJ869220 NG_070431 KX524145 MH714756 GQ221882 FJ161182 GU397348 tefl-a NA GU349001 NA NA FJ161109 MF615401 KX772769 MN442088 0Q989245 NA NA FJ161088 NA DQ767640 NA JN819299 NA NA NA NA NA NA NA NA HQ599342 HQ599375 NA NA FJ161107 NA NA NA FJ161100 NA FJ161101 FJ161092 NA FJ161102 NA NA NA NA MG844351 KX524149 MH714762 NA FJ161097 GU397339 282 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) Species name Voucher/strains Orbilia auricolor AFTOL-ID 906 CBS 547.63 O. vinosa AFTOL-ID 905 GBS:917.72 Ostreichnion sassafras CBS 322.34 Lijiangomyces laojunensis KUN-L 88703 Patellaria apiculatae MCD 096; MFLU 19-1236 P atrata CBS 958.97 P. chromolaenae MFLUCC 17-1482 Pseudocamaropycnis pini CBS 115589 Culture BA4b001 NBRC 111599 FLAS-F-59166 CBS 112412 MFLU 11-0214 MFLU 18-2218 MFLUCC 16-0611 MFLUCC 17-0319 EB QR; RLG 14189 Pseudocenococcum floridanum Psiloglonium araucanum P colihuae P macrosporum Purpurepithecium murisporum P murisporum Quasiconcha reticulata Quasiconcha sp. ZY 22.011 CGMCC 3.25498 Quasiconcha sp. LY 27-0: 2 CGMCC 3.25498 Quasiconcha sp. LVN 22.013 CGMCC 3.25498 Rhytidhysteron bannaense KUMCC 21-0483 R. bruguierae SDBR-CMU 473 R. camporesii KUNCC 22-12388 Yuccamyces citri CBS 143161 Y. pilosus CBS 579.92 Table 2. Sequences used in phylogenetic analysis of Dactylosporaceae with specimens or strains’ information and Gen- GenBank accession numbers ITS DQ491512 DQ491511 MH855548 PQ049177 MN047094 NA MT214381 KU728518 NA NA KP744466 OR225075 NA NA NA OR680490 OR680491 OR680492 OP526399 0Q943970 OR807853 MG386043 MG386044 LSU DQ470953 DQ470952 FJ161188 PQ047633 MNO17860 GU301855 MT214475 KU728557 LC095431 FJ161172 KP744511 OP612525 NG_059797 KY799174 GU397349 OR680557 OR680558 OR680559 OP526409 0Q940376 OR801302 MG386096 MG386097 tef1-a DQ471072 DQ471071 NA PQ267963 NA GU349038 MT235796 LC095383 FJ161089 NA OR140436 KY887666 KY799177 NA OR865892 OR865893 OR865894 OP572200 0Q973477 OR832866 NA NA Bank accession numbers. Newly obtained sequences are in bold font. “NA” indicates the sequence is unavailable. Species name Voucher/strains Umbilicaria sp. INB_i04503Q Umbilicaria sp. INB_i04513J Umbilicaria sp. INB_i04513L Caliciopsis orientalis CBS 138.64 C. pinea AFTOL-ID 1869 CBS 139.64 Cylindroconidiis aquaticus MFLUCC 11-0294 Fusichalara minuta CBS 709.88 MFLUCC 18-1015 MFLUCC 18-0982 Gamsomyces aquaticum G. chiangmaiensis G. longisporus CBS 118.86 G. longisporus CBS 240.89 G. stilboideus CBS 146494 Pseudosclerococcum golindoi ARAN-Fungi 6619 MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 GenBank accession numbers LSU ITS KM242300 KM242356 KM242358 NG_058741 DQ6/8097 MH236579 KX537758 MN335230 MN335229 MT020877 MT020878 MT020879 NG_073673 KM242300 KM242356 KM242358 NA NA MH236576 KX537754 MN335228 MN335227 MT020865 MT020866 MT020867 NR_171236 mtSSU NA NA NA FJ190654 FJ190653 NA KX537762 NA NA NA NA NA MK759897 283 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) GenBank accession numbers Species name Voucher/strains Sclerococcum ahtii RP 23 KY661659 KY661630 F. Hognabba 1325a (H) S. ahtii RP182 NA KY661622 CHI17-37a (H) S. chiangraiensis MFLU 16-0570 NG_066422 NR_163755 A S. deminutum RP235 N KY661629 J. Pykala 39390 (H) NA S. haliotrephum AFTOL-ID 758 FJ176855 ATCC MYA-3590 S. haliotrephum FJ713617 NA AFTOL-ID 798 S. lobariellum ARAN-Fungi 10091 NA S. martynii MZ221620 MZ221612 ie Bell S. martynii MZ221623 MZ221616 — ae S. martynii D. Haelew. F_1577a MZ221619 MZ221610 PUL F27741 S. parasiticum ARAN-Fungi 2724 MK759892 S. parasiticum RP422 KY661666 KY661646 LE 260868 S. pseudobactrodesmium OR514704 S. pseudobactrodesmium OR514705 S. sphaerale JX081674 NA MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 mtSSU KX537760 KX537759 KX537761 KY661686 NA NA NA NA NA KY661683 ORO035764 KJ766382 NA MH698503 MH698502 MK759898 KJ766383 NA NA NA MK759899 KY661690 MK759901 MK759902 MK759900 OR588037 OR588038 OR588039 OR588036 MT153924 MT153923 MT153925 MT153922 MZ676669 MF085485 KT263115 KY661689 JX081678 JX081677 JX081676 284 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) GenBank accession numbers Species name Voucher/strains LSU ITS mtSSU S. stictae KUN-L 88687 PQ407923 PQ408029 PQ415057 S. stictae KUN-L 88687-1 NA PQ408030 NA S. tardum ICMP 24355 NA NR_176187 NA S. tardum PDD 91756 NA OL709435 NA S. tardum PDD 105454 NA MK432753 NA S. stygium ARAN-Fungi 00823 NA MK759886 MK759904 S. stygium ARAN-Fungi 3395 MK759896 NA MK759903 S. stygium BHI-F312 (FH) NA MF161218 NA S. vrijmoediae NTOU 4002 KC692153 NR_138396 NA Abbreviations: ARAN-Fungi: The ARAN-Fungi Fungarium; BCC: BIOTEC Culture Collection, Thailand; BPI: United States USDA ARS National Fungus Collections, Beltsville, MD; CBS: CBS Fungal Biodiversity Center, Utrecht, The Netherlands; C6MCC: China General Mi- crobiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; CPC: Collection of PW. Crous; DAOM: Canadian Collection of Fungal Cultures, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada; FH: FH Fungarium of Helsinki University Museum, Finland; FLAS: University of Florida Herbarium, located at the Florida Museum of Natural History in Gaines- ville, Florida, USA; FMR: Fungal Biodiversity Centre of the University of Valencia, Spain; GZCC: Guizhou Culture Collection, China; GUMH: Guangxi University Microbial Herbarium, China; GZU: Herbarium of the Institute of Botany, University of Graz, Austria; HUEFS: Herbario da Universidade Estadual de Feira de Santana, Brazil; ICMP: International Collection of Microorganisms from Plants, University of Auck- land, New Zealand; JAC: University of Johannesburg Herbarium, USA; JCM: Japan Collection of Microorganisms; KRAM: Wtadystaw Szafer Institute of Botany, Polish Academy of Sciences Herbarium; KUMCC: Kunming Institute of Botany Culture Collection; KUN-HKAS: Herbarium of Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan, China; KUN-L: Lichen Herbarium of Kunming Insti- tute of Botany, Chinese Academy of Science, Yunnan, China; MFLU: the herbarium of Mae Fah Luang University, Chiang Rai, Thailand; MFLUCC: Mae Fah Luang University Culture Collection, Chiang Rai, Thailand; NBRC: NITE Biological Resource Center, Japan; NTOU: National Taiwan Ocean University; NWHC: National Wildlife Health Center of U.S. Geological Survey; PDD: Plant Disease Database at the Auckland Museum, New Zealand; PUFD: Purdue University Forestry Department; PUL: Purdue University Herbarium; RLG: The Robert L. Gilbertson Mycological Herbarium at the University of Arizona; SDBR-CMU: Sustainable Development of Biodiversity Resources, Chiang Mai University, Thailand; SICAUC:Sichuan Agricultural University Culture Collection;WU: Herbarium of the University of Vienna. Results In the analysis of Mytilinidiales, the final dataset comprised 116 taxa (Table 1) with 2246 aligned characters, including gaps (ITS 1-494 bp, LSU 495- 1346 bp, and tefl-a 1347-2246 bp). The best-fit models for each gene, de- termined using the Bayesian information criterion (BIC), were as follows: ITS: SYM+I+G4, LSU: TN+F+R4, and tefl-a: TN+F+l+G4. For the combined data- set (LSU, ITS, and tef1-a), the parameters of the GTRGAMMA model were as follows: estimated base frequencies: A = 0.24, C = 0.25, G = 0.28, T = 0.23; substitution rate: AC = 1.12, AG = 3.35, AT = 1.77, CG = 0.88, CT = 8.54, GT = 1.00; gamma distribution shape parameter (a) = 0.325118; and tree- length = 6.868758. The best-scoring RAxML tree was constructed with a final maximum likelihood (ML) optimization likelihood value of -34,803.39. Bayesian posterior probabilities (BYPP) were calculated using MCMC anal- ysis, achieving a final average standard deviation of split frequencies of 0.009998. The final tree topologies of ML and BYPP analyses were consis- tent. The best-scoring RAxML tree, based on combined LSU, ITS, and tef1-a sequence datasets, is presented in Fig. 1. The resulting phylogram distinguishes eight order-level clades, most of which are well-supported, except forthe Patellariales clade. Sevengenera forma strong- ly supported Mytilinidiales clade, with Mytilinidion appearing polyphyletic. The newly identified species clusters within the Mytilinidiales clade are closely re- lated to a Mytilinidion subclade containing eight species. The remaining Mytilin- idion species form a separate clade alongside Lophium. Halokirschsteiniothe- lia and Quasiconcha form a sister clade to the Ostreola-Mytilinidion grouping. MycoKeys 114: 277-298 (2025), DOI: 10.3897/mycokeys.114.146031 285 Qingfeng Meng et al.: Lijiangomyces, novel genus & a new lichenicolous species of Sclerococcum (China) 79/1.00 | Hysteriales 100/1.00 | Mytilinidion acicola EB 0349 Mytilinidion acicola EB 0379 400/1.00 99/1.00 Mytilinidion tortile EB 0377 \—_ Mytilinidion thujarum EB 0268 | Mpytilinidion andinense EB 0330 Mytilinidion Mytilinidion australe CBS 301.34 Mytilinidion mytilinellum CBS 303.34 | 400/1.007 Mytilinidion mytilinellum EB 0386 89/1.00 98/1.00 MN Ssess Mytilinidion didymospora MFLUCC 16-0619 (