Unveiling species diversity within Mortierellomycota from China X: Three new species in Linnemannia and one in Mortierella

245 Unveiling species diversity within Mortierellomycota from China X: Three new species in Linnemannia and one in Mortierella Xin-Yu Ji1, Zi-Ying Ding1, Wen-Xiu Liu1, Fei Li1, Heng Zhao2, Shi Wang1, Xiao-Yong Liu1,3 1 College of Life Sciences, Shandong Normal University, Jinan 250358, China 2 CAS Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China 3 Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China Corresponding author: Xiao-Yong Liu ([email protected]) Copyright: © Xin-Yu Ji 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). Research Article Abstract The species of the Mortierellaceae family are diverse and widely distributed. Four new species in this family are proposed from rhizosphere soil through a comprehensive taxonomic approach that combined multi-locus (SSU-ITS-LSU-RPB1-Act) phylogenetic analyses with detailed morphological examination. This study describes and illustrates these taxa, clarifying their morphological features from closely related species and their phylogenetic positions within the family. Linnemannia chlamydospora sp. nov. (phylogenetically proximate to L. longigemmata) is characterized by the abundant production of thick-walled chlamydospores. Linnemannia ovalispora sp. nov. (a sister taxon to L. rugosa) is distinguished by its oval sporangiospores. Linnemannia yunnanensis sp. nov. (closely allied to L. bainierella) is characterized by its oval chlamydospores and is named after Yunnan Province, its type locality. Mortierella irregularispora sp. nov. (clustering with M. parvispora) is distinguished by its irregularly shaped sporangiospores. As this is the tenth instalment of our systematic survey of Mortierellomycota diversity in China, this study expands the global species inventory of Mortierellaceae to 158. Key words: Mortierellaceae, Mucoromycota, multi-gene phylogeny, taxonomy, Zygomycota Introduction Mortierellaceae species have an important industrial and ecological value. Species within the family Mortierellaceae are notable for their ability to synthesize polyunsaturated fatty acids (PUFAs), such as arachidonic acid (ARA), which are valuable for biofuel production and widely utilized in commercial sectors (Holland 2001; Yadav et al. 2014; Telagathoti et al. 2022). Some species can also synthesize enzymes (lipase, cellulase) with potential applications in biofuels and food processing (Holland 2001; Wagner et al. 2013; Yadav et al. 2014; Telagathoti et al. 2022). Many Mortierellaceae species also produce bioactive antimicrobial metabolites that serve as effective biocontrol agents against plant pathogens (Shemshura et al. 2018). Some Mortierellaceae species can participate in organic matter mineralization as decomposers, promote soil nutrient cycling, and improve plant stress resistance (Holland 2001; Wagner et al. 2013; Yadav et al. 2014; Shemshura et al. 2018; Telagathoti et al. 2022). Academic editor: Christian Wurzbacher Received: 12 August 2025 Accepted: 31 October 2025 Published: 20 November 2025 Citation: Ji X-Y, Ding Z-Y, Liu W-X, Li F, Zhao H, Wang S, Liu X-Y (2025) Unveiling species diversity within Mortierellomycota from China X: Three new species in Linnemannia and one in Mortierella. MycoKeys 125: 245–262. https://doi.org/10.3897/ mycokeys.125.168474 MycoKeys 125: 245–262 (2025) DOI: 10.3897/mycokeys.125.168474 246 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella Additionally, certain members of this family exhibit unique ecological and biotechnological capabilities, including plant growth promotion, restructuring of rhizosphere bacterial communities, and decomposition of organic litter, highlighting their multifaceted roles in both industrial and environmental contexts (Li et al. 2020; Ozimek and Hanaka 2021). Mortierellaceae belongs to Mortierellomycota, Mortierellomycotina, Mortierellomycetes, and Mortierellales (http://www.indexfungorum.org/, accessed on 14 May 2025) (Smith et al. 2013; Wijayawardene et al. 2024). Mortierellaceae species can usually be isolated from soil, plant rhizomes, animal remains, and mosses (Tedersoo et al. 2014). The typical characteristics of Mortierellaceae species include white colony color, rosette-shaped colony morphology, and a distinctive odor generally described as resembling garlic or wet dog hair (Linnemann 1941; Gams 1977; Petkovits et al. 2011). This taxon is widely distributed throughout the country (Linnemann 1941; Holland 2001; Wagner et al. 2013; Yadav et al. 2014; Shemshura et al. 2018; Li et al. 2020; Ozimek and Hanaka 2021; Telagathoti et al. 2022). GBIF database documents Mortierellaceae from Africa (22,727 records, 5.59%), Antarctica (2,889, 0.71%), Asia (42,876, 10.55%), Oceania (47,301, 11.64%), Europe (231,446, 56.97%), North America (26,872, 6.61%) and South America (32,155, 7.91%; https:// www.gbif.org/, accessed on 22 May 2025). In summary, the species of the family Mortierellaceae are mainly concentrated in Europe. In recent years, Mortierellaceae has seen the discovery of many new species of Mortierella and Linnemannia (Holland 2001; Wagner et al. 2013; Yadav et al. 2014; Telagathoti et al. 2022), but other new genera remain to be further studied. The Catalogue of Life database contains 17 genera with a total of 144 species. Of these, Mortierella contains the largest number of species, 80, followed by Linnemannia with 24, then Podia and Entomortierella in equal third place, both with nine (https://www.catalogueoflife.org/, accessed on 22 May 2025). In this study, extensive field sampling in Yunnan and Xizang, combined with detailed laboratory analyses, resulted in the discovery of three new species in Linnemannia and one in Mortierella. The newly described species are Linnemannia chlamydospora, L. ovalispora, L. yunnanensis, and Mortierella irregularispora. These species were identified based on molecular phylogenetic evidence, morphological characteristics, and growth temperature profiles. This is the tenth report in a series of studies on the diversity of Mortierellomycota across China (Tao et al. 2024; Wang et al. 2024; Zhao et al. 2024; Ding et al. 2025a; Ding et al. 2025b; Ji et al. 2025a; Ji et al. 2025b; Wang et al. 2025). These findings not only enrich the species diversity of the family Mortierellaceae but also provide new directions for the taxonomic and evolutionary study of the family. Materials and methods Isolation Soil samples were collected from Yunnan and Xizang in 2024 following the protocols established by Zou et al. (2022) and Liu et al. (2019). Each soil sample (approximately 100 g) was transferred to sterile polyethylene bags labeled with collection date, vegetation type, elevation, and GPS coordinates (latitude/longitude) (Rathnayaka et al. 2025). All samples were stored at 247 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella 4 °C post-transportation until laboratory processing. Pure strains were isolated from the soil samples using a combination of soil dilution plating and moist-chamber cultivation methods (Zhao et al. 2021). Soil suspensions were prepared by homogenizing approximately 1 g of soil sample in 10 mL of sterile deionized water within a 15 mL conical tube, followed by mechanical agitation on a vortex mixer for 25 minutes at 1,500 rpm to achieve thorough dispersion. Serial dilutions were performed by transferring 1 mL of the primary suspension into 9 mL of sterile deionized water, generating a 10−2 dilution. This process was repeated sequentially to obtain 10−3 and 10−4 dilutions. For fungal isolation, 200 μL aliquots of the 10−3 and 10−4 dilutions were aseptically pipetted onto Rose Bengal Chloramphenicol (RBC) agar plates. The medium contained per liter: peptone (5.00 g), KH2PO4 (1.00 g), MgSO4·7H2O (0.50 g), Rose Bengal dye (0.05 g), glucose (10.00 g), chloramphenicol (0.10 g), and agar (15.00 g), adjusted to pH 6.8 ± 0.2 (Corry et al. 1995). Samples were evenly distributed using flame-sterilized glass spreaders and incubated at 26 °C under light-restricted conditions for 2–5 days to promote fungal colony development. Subsequently, fungal colonies exhibiting active hyphal growth margins were selectively sub-cultured onto fresh Potato Dextrose Agar (PDA: 20 g/L glucose, 200 g/L potato infusion, 20 g/L agar, pH 5.6 ± 0.2) or malt extract agar (MEA: 33.6 g/L malt extract, 20 g/L agar) using inoculation needles. Macromorphological features were documented with a high-resolution digital imaging system (Canon PowerShot G7X, Canon, Tokyo, Japan). For the wet-chamber protocol, homogenized soil aliquots (1 g) were aseptically spread on PDA plates, sealed, and inverted incubated at 15 °C (±0.5 °C) in the dark to simulate the subsurface niche. After 48–72 h of incubation, isolate primary fungal colonies by quadrant streak using flame-sterilized inoculation loops. After two days, the agar containing mycelia at the edge of the colony was transferred to fresh PDA or MEA, and culture as described above. After about five days, the strain grew well. Morphological observation Lactophenol cotton blue (LPCB) staining droplets were added to the glass slide. Then, a small piece of tape was touched to the mycelial surface, causing some hyphae to adhere to it. The stained specimen was immersed in a lactol cotton blue (LCB) solution for easy observation morphological analysis utilized a stereoscope (Olympus SZX10, Olympus, Tokyo, Japan) and a light microscope (Olympus BX53, OLYMPUS, Tokyo, Japan), and a high-definition color digital camera (Olympus DP80 OLYMPU, Tokyo, Japan) to observe hyphal structures and reproductive organs (Jiang et al. 2024; Tao et al. 2024; Wang et al. 2024; Ding et al. 2025a; Ding et al. 2025b; Ji et al. 2025a; Ji et al. 2025b; Wang et al. 2025). Morphometry analysis was performed using Digimizer software (v5.6.0) with at least 15 individuals measured per morphological trait. To determine the minimum and maximum growth temperatures of the strains, the temperature gradient method was used. First, initiate a thermal acclimatization protocol by incubating the primary culture at 10 °C (±0.5 °C) for 48 h to stabilize fungal metabolism. Subsequently, the incubation temperature was reduced by 1 °C increments per day until radial growth stopped. The final temperature before growth arrest is designated as 248 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella the minimum growth temperature. All strains were stored in 10% sterile glycerol at -20 °C. The living cultures were stored in the China Microbiological Culture Collection Center, Beijing, China (CGMCC). Equivalent strains were preserved in the Shandong Normal University Culture Collection (XG). Dry cultures of types were submitted to the Herbarium Mycologicum Academiae Sinicae, Beijing, China (Fungarium; HMAS). The taxonomic information was deposited to the Fungal Names repository (https://nmdc.cn/fungalnames/). DNA extraction, PCR amplification, and sequencing Genomic DNAs were extracted using the DNA Extraction Kit (Cat. No.: 70409-20; Beaver Biomedical Engineering Co., Ltd.) (Doyle et al. 1990; Wang et al. 2023). Target regions (ITS, LSU, SSU, RPB1, and Act) were amplified through PCR with primer pairs and protocols outlined in Table 1. Reactions were performed in a 25 μL final volume containing 12.5 μL of 2 × Hieff Canace Plus PCR Master Mix with dye (Yeasen Biotechnology, Cat No. 10154ES03), 9.5 μL of ddH2O, 1 μL of forward primer (10 μM), 1 μL of reverse primer (10 μM), and 1 µL of template genomic DNA (1 ng/μL). Amplified products were visualized on a 2% agarose gel at 254 nm and purified using the Gel Extraction Kit (Cat# AC0101-C; Shandong Sparkjade Biotechnology Co., Ltd.), designed for efficient recovery of DNA fragments ranging from 100 bp to 20 kb (Zhang et al. 2022; Zhang et al. 2025). The same supplier also provided the RNA Rapid Extraction Kit (Cat# AC0305; Shandong Sparkjade Biotechnology Co., Ltd.), which was available for total RNA extraction had transcriptomic analyses been required. DNA sequencing was performed by Beijing Tsingke Biotech Co., Ltd. All sequences generated in this study were deposited in GenBank (accession numbers provided in the Suppl. material 1), in accordance with standardized submission protocols for public data accessibility. Phylogenetic analyses The newly acquired sequence data were processed using MEGA v7 to ensure consistency (Kumar et al. 2016; Larsson 2014). Reference sequences for Mortierellaceae were retrieved from GenBank using the methodology Table 1. PCR information used in this study. Locus PCR primers Primer sequences (5’–3’) PCR cycle Reference ITS ITS5 ITS4 GGA AGT AAA AGT CGT AAC AAG G TCC TCC GCT TAT TGA TAT GC 95 °C 5 min; (95 °C 30 s, 55 °C 30 s, 72 °C 1 min) × 35 cycles; 72 °C 10 min (White et al. 1990) LSU LR0R LR5 GTA CCC GCT GAA CTT AAG C TCC TGA GGG AAA CTT CG 95 °C 5 min; (94 °C 30 s, 52 °C 45 s, 72 °C 90 s) × 30 cycles; 72 °C 10 min (Hurdeal et al. 2023) SSU NS1 NS4 GTA GTC ATA TGC TTG TCT CC CTT CCG TCA ATT CCT TTA AG 95 °C 5 min; (94 °C 60 s, 54 °C 50 s, 72 °C 60 s) × 37 cycles; 72 °C 10 min (Hurdeal et al. 2023) RPB1 RPB1-Af RPB1-Cr GAR TGY CCD GGD CAY TTY GG CCN GCD ATN TCR TTR TCC ATR TA 95 °C 3 min; (94 °C: 40 s, 60 °C: 40 s, 72 °C: 2 min) × 9 (94 °C: 45 s, 55 °C: 1.5 min, 72 °C: 2 min) × 37 cycles; 72 °C 10 min (Stiller and Hall 1997) Act ACT-1 ACT-4R TGG GAC GAT ATG GAI AAI ATC TGG CA TC ITC GTA TIC TIG CTI IGA IAT CCA CA T 95 °C 3 min; (95 °C: 60 s, 55 °C: 60 s, 72 °C: 1 min) × 30 cycles; 72 °C 10 min (Voigt and Wöstemeyer 2000) 249 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella of Telagathoti et al., and phylogenetic analyses were conducted for each genetic marker (Telagathoti et al. 2022). The evolutionary relationships within Mortierellaceae were reconstructed through both Maximum Likelihood (ML) and Bayesian Inference (BI) approaches, implemented via the CIPRES Science Gateway (https://www.phylo.org/, accessed 16 May 2025) (Nie et al. 2020a; Nie et al. 2020b). The maximum likelihood (ML) analysis was performed using RAxML version 8.2.4 on the CIPRES Science Gateway Version 3.3 platform, with 1,000 bootstrap replicates conducted to assess the robustness of the phylogenetic tree (Miller et al. 2010; Nguyen et al. 2015). The Bayesian inference (BI) analysis was conducted using the GTR + I + G model, with samples collected every 1,000 generations. A total of eight cold Markov chains were run concurrently for two million generations (Ronquist et al. 2012; Stamatakis 2014). The resulting phylogenetic trees were visually optimized and annotated using iTOL (https://itol.embl.de, accessed May 16, 2025) and Adobe Illustrator CC 2019 (Wang et al. 2023). Results Phylogeny For Linnemannia, phylogenetic analyses were performed on a dataset comprising 43 strains representing 34 species, with Mortierella longicollis (CBS 879.97) as an outgroup (Genbank numbers see Suppl. material 1: table S1). The sequence matrix comprises 4,863 concatenated characters: 1–690 (ITS), 691– 1,672 (LSU), 1,673–2,728 (SSU), 2,729–4,099 (RPB1), and 4,100–4,863 (Act). Among these characters, 1,130 are parsimony-informative, along with 3,417 constant and 316 parsimony-uninformative. Bayesian tree topology is congruent with that of the ML tree (Fig. 1). For Mortierella, phylogenetic analyses were performed on a dataset comprising 89 strains representing 75 species, with Umbelopsis autotrophica (CBS 310.93) as an outgroup (Genbank numbers see Suppl. material 1: table S2). The sequence matrix comprises 5,292 concatenated characters: 1–962 (ITS), 963–1,968 (LSU), 1,969–3,049 (SSU), 3,050–4,422 (RPB1), and 4,423–5,292 (Act). Among these, 1,806 are parsimony-informative, along with 2,581 constant and 905 parsimony-uninformative. Bayesian tree topology is consistent with the ML tree (Fig. 2). Taxonomy Linnemannia chlamydospora X.Y. Ji, H. Zhao & X.Y. Liu, sp. nov. Fig. 3 Fungal Names: FN 572057 Type. China • Xizang, Nyingchi City, Bayi District (29°33'40"N, 94°33'13"E, altitude 3713 m), from soil, 29 August 2024, X.Y. Ji, holotype HMAS 354073, ex-holotype living culture CGMCC 3.28892 (=XG10460-10-1). Etymology. The epithet chlamydospora (Lat.) refers to a larger number of chlamydospores. 250 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella Figure 1. The Maximum Likelihood phylogenetic tree for the genus Linnemannia based on combined ITS, LSU, SSU, RPB1, and Act sequences with Mortierella longicollis as outgroup. Node supports are indicated by two metrics: Maximum Likelihood Bootstrap Values (left, MLBV ≥ 70%) and Bayesian Inference Posterior Probabilities (right, BIPP ≥ 0.90), separated by a slash (/). Novel species are emphasized in red. Bold entries with asterisks (*) denote ex-type or ex-holotype strains. The scale bar in the lower left represents 0.1 substitutions per site. M.longicollis CBS 209.32* L.friederikiana Pr3s8 L.hyalina CBS 223.35 L.scordiella HFSF81* L.sclerotiella CBS 529.68* L.acrotona CBS 386.71* L.olea CGMCC 3.28579* L.zychae CBS 316.52* L.stellaris ks2-4* L.nimbosa HFSF57* L.exigua NNIBRFG5521 L.mannui Pr2s5 L.fatshederae CBS 388.71* L.elizabethkennyiae BRIP 74948a* L.fluviae EML-YR25716-1* L.gamsii CBS 749.68* L.diaoluoshan XG08196-6* L.schmuckeri CBS 295.59* L.camargensis CBS 221.58* L.camargensis CBS 221.58* L.amoeboidea CBS 889.72* L.tamarindoides CGMCC 3.28576* L.rhizomorpha XG07310-1* L.biramosa RS5 L.biramosa SYFGD6-2 L.biramosa SYFGP2-1 L.nantahalensis CBS 610.70* L.brevisphora CGMCC 3.28577* L.solitaria OAS3* L.elongata 7 L.rugosa XG10541-6* L.ovalispora XG09524-11-2 L.ovalispora CGMCC 3.28891* L.yunnanensis CGMCC 3.28890* L.yunnanensis XG08668-7-2 L.longigemmata CBS 653.93* L.rotunda CGMCC 3.28764* L.rotunda XG08755-7-2 L.chlamydospora CGMCC 3.28892* L.chlamydospora XG10460-10-2 L. bainierella Pr1s13 L. bainierella Pr1s20 L. bainierella Pr1s21 91/0.99 99/0.99 99/0.98 100/0.99 92/0.99 93/1 73/0.95 78/0.92 81/0.94 93/0.97 100/1 73/0.96 75/0.99 95/0.99 83/0.96 91/0.99 0.1 251 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella Umbelopsis autotrophica CBS 310.93* M.longicollis CBS 209.32* M.capitata CBS 110.640 M.wolfii CBS 651.93 M.wolfii CBS 209.69 M.wolfii CBS 612.70 M.microzygospora CBS 880.97* M.epigama CBS 489.70* M.verticillata CBS 346.66 M.humilis FSU828 M.humilis CBS 745.68 M.humilis CBS 222.35* M.horticola CBS 305.52* M.clonocystis CBS 357.76* M.minutissima CBS 307.52 M.epicladia CBS 355.76* M.lapis OBS3* M.antarctica CBS 609.70* M.triangularis OAS8 M.alpina CBS 210.32 M.alpina CBS 210.32* M.multispora KUMCC 20-0005* M.calciphila WA 18944* M.formicicola CBS 109.589 M.paraensis CBS 547.89 M.beljakovae CBS 123.72* M.lignicola CBS 207.37* M.gemmifera CBS 134.45* M.kuhlmanii CBS 157.71* M.spinospora XG06904-41 M.echinosphaera CBS 575.75* M.chlamydospora CBS 120.34 M.mutabilis CBS 308.52* M.stylospora CBS 211.32* M.simplex CBS 243.82 M.angusta CBS 293.61* M.parazychae CBS 868 71* M.strangulata CBS 455.67* M.rostafinskii CBS 522.70* M.selenospora CBS 811.68* M.hypsicladia CBS 116.202* M.indohii FSU830 M.indohii FSU831 M.indohii CBS 720.71* M.polycephala FSU696 M.polycephala FSU866 M.polygonia CBS 685.71* M.acuta XG08182-4-2 M.acuta CGMCC 3.28761* M.amoeboidea CBS 889.72* M.yunnanensis KUMCC 20-0009* M.globalpina CBS 360.70* M.basiparvispora CBS 517.72* M.formicae WA 49853* M.dichotoma CBS 221.35* M.tibetensis XG00421-2-2 M.tibetensis CGMCC 3.28763* M.parvispora CBS 311.52 M.irregularispora CGMCC 3.28893* M.irregularispora XG00435-2-2 M.macrocystis CBS 314.85 M.oedema CGMCC 3.28762* M.oedema XG00420-1-2 M.elongatula CBS 488.70* M.cystojenkinii CBS 456.71* M.pulchella CBS 312.52 M.turficola CBS 432.76* M.fimbricystis CBS 943.70* M.armillariicola CBS 914.73* M.bainieri CBS 220.35 M.zonata CBS 228.35* M.verrucosa CBS 181.73 M.histoplasmatoides CBS 321.78* M.cogitans CBS 879.97* M.sclerotiella CBS 529.68* M.gamsii CBS 749.68* M.gamsii CBS 551.73 M.sarnyensis CBS 122.72* M.nantahalensis CBS 610.70* M.wuyishanensis CBS 370.95* M.biramosa CBS 370.95 M.schmuckeri CBS 295.59* M.camargensis CBS 221.58* M.zychae CBS 316.52* M.exigua CBS 655.68* M.acrotona CBS 386.71* M.elongata FSU823 M.elongata FSU822 M.rishikesha CBS 652.68* 81/0.90 99/1 96/1 100/1 100/1 92/1 96/1 97/0.99 100/1 100/0.99 100/1 100/1 81/1 93/1 100/1 100/0.99 100/1 100/1 73/1 81/0.99 91/1 100/1 100/1 100/1 70/1 98/1 100/1 99/0.99 100/0.99 95/1 100/1 82/0.99 100/0.99 95/1 71/1 98/1 100/1 0.1 Figure 2. The Maximum Likelihood phylogenetic tree for the genus Mortierella based on combined ITS, LSU, SSU, RPB1, and Act sequences with Umbelopsis autotrophica as an outgroup. Node supports are indicated by two metrics: Maximum Likelihood Bootstrap Values (left, MLBV ≥ 70%) and Bayesian Inference Posterior Probabilities (right, BIPP ≥ 0.90), separated by a slash (/). Novel species are emphasized in red. Bold entries with asterisks (*) denote ex-type or ex-holotype strains. The scale bar in the lower left represents 0.1 substitutions per site. 252 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella Description. Colonies on PDA at 16 °C for 5 d, reaching 70 mm diameter, fast growing with a rate of 14 mm/d, garlic smell, annual ring-like. Hyphae hyaline, 2.0–7.8 µm wide (n = 15, x – = 4.8). Sporangia mostly spherical, smooth, hyaline, 9.0–12.7 µm in diameter (n = 15, x – = 11.2). Sporangiospores hyaline, smooth, mostly round, 5.8–12.7 µm in diameter (n = 15, x – = 9.6). Chlamydospores abundant, oval, round, and irregular, 11.2–33.6 µm long and 6.8–21.7 µm wide (n = 15, x – =17.4 × 13.0 µm). Zygospores not found. Figure 3. Linnemannia chlamydospora ex-holotype CGMCC 3.28892. a, b. Colonies on PDA (a. obverse; b. reverse); c, d. Sporangia; e–i. Chlamydospores; j–m. Sporangiospores. Scale bars: 10 µm (c–m). 253 MycoKeys 125: 245–262 (2025), DOI: 10.3897/mycokeys.125.168474 Xin-Yu Ji et al.: Three new species in Linnemannia and one in Mortierella Temperature requirements. Minimum growth temperature 4 °C and maximum growth temperature 28 °C. Additional strains examined. China • Xizang, Nyingchi City, Bayi District (29°33'40"N, 94°33'13"E, altitude 3713 m), from soil, 29 August 2024, X.Y. Ji, living culture XG10460-10-2. Notes. The phylogenetic analysis showed that the new species L. chlamydospora is closely related to L. longigemmata (Fig. 2). It is distinguished from L. longigemmata by 55/621 characters in ITS sequences. Morphologically, compared to L. longigemmata, the new species has larger sporangiospores (5.8–12.7 µm vs 5.0–9.0 µm) and smaller chlamydospores (11.2–33.6 × 6.8–21.7 µm vs up to 60.0 µm). Linnemannia ovalispora X.Y. Ji, H. Zhao & X.Y. Liu, sp. nov. Fig. 4 Fungal Names: FN 572920 Type. China • Yunnan Province, Yuxi City, Research and service area of Hongta District (24°15'41"N, 102°28'58"E, altitude 1632.18 m), from soil, 15 March 2024, X.Y. Ji, holotype HMAS 354072, ex-holotype living culture CGMCC 3.28891 (=XG09524-11-1). Etymology. The epithet ovalispora (Lat.) refers to the oval sporangiospores. Figure 4. Linnemannia ovalispora ex-holotype CGMCC 3.28891. a, b. Colonies on MEA (a. obverse; b. reverse); c, d. Chlamydospores; e–g. Sporangiospores. 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NA stands for “not available”. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) 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.125.168474.suppl1