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Research Article
Three new species of Inosperma (Agaricales, Inocybaceae) from Tropical Africa
expand article infoHyppolite L. Aïgnon, Sana Jabeen§, Arooj Naseer|, Nourou S. Yorou, Martin Ryberg
‡ University of Parakou, Parakou, Benin
§ University of Education, Lahore, Pakistan
| University of the Punjab, Lahore, Pakistan
¶ Uppsala University, Uppsala, Sweden
Open Access

Abstract

Here, we describe three new species of Inosperma from Tropical Africa: Inosperma africanum, I. bulbomarginatum and I. flavobrunneum. Morphological and molecular data show that these species have not been described before, hence need to be described as new. The phylogenetic placements of these species were inferred, based on molecular evidence from sequences of 28S and RPB2. Additional analysis using ITS dataset shows interspecific variation between each species. Phylogenetic analyses resolve I. flavobrunneum in Old World Tropical clade 1 with weak support, I. bulbomarginatum is sister of Old World Tropical clade 1 and I. africanum is indicated as sister to the rest of Inosperma. Complete description and illustrations, including photographs and line drawings, are presented for each species. A new combination of Inocybe shawarensis into Inosperma is also proposed.

Keywords

Ectomycorrhizal, molecular systematics, phylogeny, taxonomy, West Africa

Introduction

Inocybaceae Jülich (Basidiomycota, Agaricales) is a family of ectomycorrhizal species, forming symbiotic association with more than 23 families of vascular plants (Matheny et al. 2020). The family is diverse with an estimated 1050 species distributed worldwide (Matheny and Kudzma 2019; Matheny et al. 2020). The number of species described will continue to increase as new habitats are explored (Matheny and Watling 2004; Esteve-Raventós 2014; Latha and Manimohan 2015, 2016; Matheny et al. 2017; Naseer et al. 2018; Jabeen and Khalid 2020).

Recently, Inocybaceae was revised to include seven genera, Auritella Matheny & Bougher, Inocybe (Fr.) Fr., Inosperma (Kühner) Matheny & Esteve-Rav., Mallocybe (Kuyper) Matheny, Vizzini & Esteve-Rav., Nothocybe Matheny & K.P.D. Latha, Pseudosperma Matheny & Esteve-Rav. and Tubariomyces Esteve-Rav. & Matheny (Matheny et al. 2020). Inosperma is represented by more than 55 known species that are distributed in Africa, Asia, Australasia, Europe, North America and northern South America (Matheny et al. 2020). Typically, the species of the genus are characterised by a radially fibrillose and rimose or squamulose pileus; smooth, ellipsoid or phaseoliform basidiospores; and absence of metuloid hymenial cystidia. In addition, many species of Inosperma have odours that are fruity, pleasant, like honey, fishy, pelargonium or otherwise distinct (Matheny et al. 2020). Phylogenetically the genus is monophyletic with four major clades: the Maculata clade (Larsson et al. 2009), I. sect. Inosperma and two clades from the Old World tropics (Pradeep et al. 2016; Matheny et al. 2020).

In this study, we describe three new species of Inosperma from West Africa, based on morphological characters, as well as analysing their phylogenetic position using multigene molecular analysis of 28S and RPB2 sequences data.

Material and methods

Study area and specimen sampling

Specimens were collected in Benin in Okpara Forest (9°15.13'N, 2°43.05'E), N’dali Forest Reserve (09°45.73'N, 2°19.93'E), Toui-Kilibo Forest Reserve (8°32.74'N, 2°40.42'E) and Alibori Superieur Forest Reserve (10°23.76'N, 2°5.15'E). Additionally, specimens were collected in, Burkina Faso in the Forest Reserve of Kou (10°55.86'N,4°51.83'W); Ivory Coast in Gbeke Region (7°40.52'N, 4°54.48'W), Guinea in National Park of Haut Niger (10°30.76'N, 9°57.68'W) and Togo in Central Region (09°20.38'N, 1°14.44'E).

The habitats are woodland dominated by Isoberlinia doka Craib & Stapf, I. tomentosa (Harms) Craib et Stapf, Uapaca togoensis Pax or gallery forest dominated by Berlinia grandiflora (Vahl) Hutch. Specimens were preserved by drying on an electric dryer (type Stöckli Dörrex) for 24 hours at 45 °C. All studied materials are deposited at the Mycological Herbarium of Parakou University (UNIPAR).

Morphological analyses

Specimens were photographed in the field with a digital camera Sony FE. Colour codes are described using Kornerup and Wanscher (1978). For anatomical analyses, samples

of specimens were rehydrated and examined directly in 3% potassium hydroxide (KOH) and Congo red. Drawings of microscopic characters were made with the aid of a drawing tube attached to a Leica DM2700. Microscopic characters were drawn at magnification 1000×. Spore measurements were made from 40 spores for each species. We measured length (L) and width (W) of the basidiospores and calculated the ratio Q = L / W. Measurements of basidiospores and basidia excluded the apiculus and sterigmata, respectively and are given as (a–)b–c(–d), where (a) = extreme minimum value, range b–c contains minimum of 90% of the calculated values and (d) = extreme maximum value as used in Aïgnon et al. (2021).

Molecular analyses

DNA extraction, PCR and sequencing

Genomic DNA was extracted from dried specimens by QIAGEN® plant mini kit following the manufacturer’s instructions and PCR products were cleaned using ExoSAP-IT (Bell 2018). The internal transcribed spacer regions (ITS), portions of the nuclear large subunit ribosomal RNA gene (28S) and DNA-directed RNA polymerase II subunit (RPB2) were amplified. For sequencing of the ITS region, we used the primers ITS1F and ITS4 (White et al. 1990; Gardes and Bruns 1993), for LSU we used LR0R, LR7 and internal primers LR5 and LR3R (Vilgalys and Hester 1990; Cubeta et al. 1991; Rehner and Samuels 1995) and for RPB2, we used primer pairs b6F and b7.1R (Matheny 2005). PCR products were cleaned and sequenced at Macrogen Inc. (Macrogen Europe B.V., Amsterdam, Netherlands) using the same primers as those used for PCR.

Sequence alignments and phylogenetic analyses

Nineteen new sequences were generated (Table 1). Sequences were BLAST searched against NCBI and similar sequences were retrieved from GenBank (Benson et al. 2010). The sequences of ITS, 28S and RPB2 were aligned separately in MAFFT V7.464 (Katoh et al. 2019). Alignment is available online in TreeBase under accession number 27445 (http://purl.org/phylo/treebase/phylows/study/TB2:S27445).

For phylogenetic analysis, the dataset of 28S and RPB2 was generated using Geneious 7.0.2 (Drummond et al. 2010) and partitioned in 28S, RPB2 codon position 1, RPB2 codon position 2, RPB2 codon position 3 and the intron in RPB2 separately (Suppl. material 1). We tested for the best partitioning scheme and best model for each partition using Modelfinder (Kalyaanamoorthy et al. 2017). It was indicated that keeping all the partitions was the best way to proceed. Maximum Likelihood (ML) analysis was performed with IQTREE 1.6.12 (Nguyen et al. 2015). Branch support was assessed with 1000 replicates of ultrafast bootstrap replicates and approximate likelihood ratio test [aLRT] and Shimodaira-Hasegawa [SH]-aLRT (SH-Alrt) test with 1000 replicates (Hoang et al. 2017).

For Bayesian Inference (BI) analyses, GTR models with gamma-distributed rate heterogeneity and a proportion of invariant sites parameter were assigned to each partition as indicated above, using MrBayes 3.2.7 (Ronquist et al. 2012), set as follows: lset applyto = (all), nst = 6, rates = invgamma, ngammacat = 4, sampling frequency = 1000 and the command “unlink” was used to unlink parameters across characters on partitioned datasets. Two independent Markov Chain Monte Carlo (MCMC) processes were executed, each in four chains for 20 million generations. Posterior probabilities (BPP) were calculated after burning the first 25% of the posterior sample and ensuring that this threshold met the convergence factors described above. The sequences from Pseudosperma lepidotellum (Matheny & Aime) Matheny & Esteve-Rav., P. pluviorum (Matheny & Bougher) Matheny & Esteve-Rav., Pseudosperma sp. PBM3751 and Pseudosperma sp. TR194-02 were used as outgroup taxa. We also produced trees using ITS database only to show interspecific variation between each species.

Table 1.

List of species, geographic origin and GenBank accession numbers of ITS, 28S and RPB2 sequences used in the molecular analysis; the new species and new combinations are in bold.

Species Voucher Country ITS 28S RPB2 References
Auritella brunnescens Matheny & Bougher PBM3174 Australia KJ702344 JQ313571 KJ702349 Matheny et al. (2017)
Auritella dolichocystis Matheny, Trappe & Bougher Trappe 24844 New South Wales AY380371 AY337371 Matheny (2005)
Auritella fulvella Matheny & Bougher BRI:AQ669485 Australia KJ702355 KJ702353 KJ702357 Matheny et al. (2017)
Auritella hispida Matheny & T.W. Henkel TH1009, TH10379 Cameroon KT378203 KT378208 KT378215 Matheny et al. (2017)
Auritella serpentinocystis Matheny, Trappe &Bougher ex Matheny & Bougher PBM3188 Australia KJ729858 JQ313559 KJ756402 Matheny et al. (2017)
Auritella spiculosa Matheny & T.W. Henkel MCA7031, TH9866 Cameroon MF374763 KT378206 KT378214 Matheny et al. (2017)
Inosperma adaequatum (Britzelm.) Matheny & Esteve-Rav. JV 16501F, JV11290F Finland JQ801381 JQ815407 AY333771 Matheny et al. (2020)
I. africanum Aïgnon, Yorou & Ryberg MR00387 Togo MN096189 MN097881 MT770739 This study
HLA0361 Benin MT534295 MT560735
HLA0383 Benin MT534298 MT560733
HLA0353 Benin MT534299
BRF4157 Benin MK908843 Unpublished
I. akirnum (K.P.D. Latha & Manimohan) Matheny & Esteve-Rav. CAL 1358 India NG_057279 KY553236 Latha and Manimohan (2016)
I. apiosmotum (Grund& D.E. Stuntz) Matheny & Esteve-Rav. AU10560, TENN:062779 Canada, USA HQ201336 JN975022 JQ846463 Ryberg and Matheny (2012)
I. bongardii (Weinm.) Matheny & Esteve-Rav. EL9406 Sweden FN550943 FN550943 Unpublished
I. bulbomarginatum Aïgnon, Yorou & Ryberg MR00357 Benin MN096190 MN097882 MN200775 This study
HLA0373 Benin MT534301
HLA0389 Benin MT534302
HLA0417 Benin MT534300 MT560734
PC96082 Zambia JQ801412 JN975027 Ryberg and Matheny (2012)
I. calamistratoides (E. Horak) Matheny & Esteve-Rav. PBM3384 Australia JQ815415 KJ729949 Latha and Manimohan (2016)
I. calamistratum (Fr.) Matheny & Esteve-Rav. PBM1105 USA JQ801386 JQ815409 JQ846466 Pradeep et al. (2016)
I. carnosibulbosum (C.K. Pradeep & Matheny) Matheny & Esteve-Rav. TBGT:12047 India KT329448 KT329454 KT32944 Pradeep et al. (2016)
I. cervicolor (Pers.) Matheny & Esteve-Rav. SJ04024, TURA:4761 Sweden, Finland AM882939 AM882939 JQ846474 Ryberg et al. (2008)
I. cookei (Bres.) Matheny & Esteve-Rav. EL70A03 Sweden AM882953 AM882953 Ryberg et al. (2008)
I. cyanotrichium (Matheny, Bougher& G.M. Gates) Matheny & Esteve-Rav TENN:065729 Australia JQ815418 KJ729948 Unpublished
I. flavobrunneum Aïgnon, Yorou & Ryberg HLA0367 Benin MN096199 MT536754 This study
HLA0372 Benin MT534290 MT536756
I. geraniodorum (J. Favre) Matheny & Esteve-Rav. EL10606 Sweden FN550945 FN550945 Latha and Manimohan (2016)
I. gregarium (K.P.D. Latha & Manimohan) Matheny & Esteve-Rav. CAL 1309 India KX852305 KX852306 KX852307 Latha and Manimohan (2016)
I. lanatodiscum (Kauffman) Matheny & Esteve-Rav. PBM2451 USA JQ408759 JQ319688 JQ846483 Latha and Manimohan (2016)
I. maculatum (Boud.) Matheny & Esteve-Rav. MR00020 Sweden AM882958 AM882958 Ryberg et al. (2008)
I. maximum (A.H. Sm.) Matheny & Esteve-Rav. PBM 2222,UBC F33244 USA,Canada MG953983 EU569854 Matheny et al. (2009)
I. misakaense (Matheny & Watling) Matheny &Esteve-Rav. 96234 (PC) Zambia JQ801409 EU569874 EU569873 Pradeep et al. (2016)
I. mutatum (Peck) Matheny & Esteve-Rav. PBM4108, PBM2953 USA MG773837 JQ994476 JQ846488 Matheny et al. (2020)
I. neobrunnescens (Grund & D.E. Stuntz) Matheny &Esteve-Rav. PBM 2452 USA EU569868 EU569867 Matheny et al. (2009)
I. quietiodor (Bon) Matheny & Esteve-Rav. PAM01091310 France FJ936168 FJ936168 Larsson et al. (2009)
I. rhodiolum (Bres.) Matheny & Esteve-Rav. PAM00090117 France FJ904176 FJ904176 Larsson et al. (2009)
I. rimosoides (Peck) Matheny & Esteve-Rav. PBM 2459, PBM3311 USA JQ801414 JQ815426 DQ385884 Latha and Manimohan (2016)
I. rubricosum (Matheny & Bougher) Matheny & Esteve-Rav. PBM3784 Australia NG_057260 KM406230 Horak et al. (2015)
I. shawarense (Naseer & Khalid) Aïgnon & Naseer FLAS-FS9456 Pakistan KY616965 KY616966 Naseer et al. (2018)
Inosperma sp. DB166 Democratic Republic of the Congo KT461385 Bauman et al. (2016)
Inosperma sp. PC 96013 Zambia JQ801383 JQ815408 EU600882 Matheny et al. (2009)
Inosperma sp. BB3233 Zambia JQ801415 EU600885 Matheny et al.(2009)
Inosperma sp. G1842 Zambia MK278245 Unpublished
Inosperma sp. TR220_06 Papua New Guinea JQ801416 JN975017 JQ846496 Ryberg and Matheny (2012)
Inosperma sp. L-GN3a Papua New Guinea JX316732 Tedersoo and Põlme (2012)
Inosperma sp. Zam07 Zambia FR731653 Tedersoo et al. (2011)
Inosperma sp. PBM3406 Australia JQ815431 JQ846498 Unpublished
Inosperma sp. TJB10045 Thailand KT600658 KT600659 KT600660 Pradeep et al. (2016)
Inosperma sp. PC 96073 Zambia JQ801417 EU600870 EU600869 Matheny et al. (2009)
Inosperma sp. PC:96080 Zambia JQ801382 Unpublished
I. vinaceobrunneum (Matheny, Ovrebo & Kudzma) Haelew. TENN:062709, PBM 2951 USA FJ601813 NG_067775 JQ846478 Matheny and Kudzma (2019)
I. viridipes (Matheny, Bougher & G.M. Gates) Matheny & Esteve-Rav. PBM3767 Australia NR_153168 KP171094 KM656138 Latha and Manimohan (2016)
I. virosum (K.B. Vrinda, C.K. Pradeep, A.V. Joseph & T.K. Abraham ex C.K. Pradeep, K.B. Vrinda& Matheny) Matheny & Esteve-Rav. TBGT:753 India KT329452 KT329458 KT329446 Pradeep et al. (2016)
Mallocybe myriadophylla (Vauras & E. Larss.) Matheny & Esteve-Rav. JV19652F Finland DQ221106 AY700196 AY803751 Matheny et al. (2007)
M. subdecurrens (Ellis & Everh.) Matheny & Esteve-Rav. REH10168 USA MH024850 MH024886 MH577503 Matheny et al. (2020)
M. terrigena (Fr.) Matheny, Vizzini & Esteve-Rav. EL11704, JV 16431 Sweden AM882864 AY380401 AY333309 Matheny and Ammirati (2003); Matheny (2005)
M. tomentosula Matheny & Esteve-Rav. PBM4138 USA MG773814 MK421969 MH577506 Matheny et al. (2020)
M. unicolor (Peck) Matheny & Esteve-Rav. PBM 1481 USA AY380403 AY337409 Matheny (2005)
Pseudosperma lepidotellum (Matheny & Aime) Matheny & Esteve-Rav. TENN066442 Guyana JN642233 NG_042597 MH577508 Matheny et al. (2012)
P. pluviorum (Matheny & Bougher) Matheny & Esteve-Rav. BRI:AQ794010, PERTH:08556466 Australia NG_057259 KM406221 Horak et al. (2015)
Pseudosperma sp. PBM3751 Australia KP636851 KP171053 KM555145 Pradeep et al. (2016)
Pseudosperma sp. TR194-02 (M) Papua New Guinea JQ408793 JN975032 JQ421080 Ryberg and Matheny (2012)
Tubariomyces inexpectatus (M. Villarreal, Esteve-Rav., Heykoop & E. Horak) Esteve-Rav. & Matheny AH25500 AH20390 Spain GU907095 EU569855 GU907088 Matheny et al. (2009), Alvarado et al. (2010)
T. similis Della Magg., Tolaini & Vizzini RFS0805 Spain GU907096 GU907092 GU907089 Alvarado et al. (2010)
T. hygrophoroides Esteve-Rav., P.-A. Moreau & C.E. Hermos. P05112008 France GU907097 GU907094 GU907090 Pradeep et al. (2016)

Results

Phylogenetic analyses

Inosperma is indicated as monophyletic with full bootstrap support. All three of the species described here, Inosperma africanum I. bulbomarginatum and I. flavobrunneum, are members of this genus. Phylogenetically, I. africanum is indicated as sister to the rest of Inosperma, with full support (99.9% SH-aLRT values, 100% ML ultrafast bootstrap, 1 BPP). The Old World Tropical clade 1 is retrieved with strong support (93.8% SH-aLRT values, 99% ML bootstrap, 1 BPP) and I. bulbomarginatum is indicated as the sister of Old World Tropical clade 1 with full bootstrap support (100% SH-aLRT values, 100% ML Ultrafast bootstrap, 1 BPP). The sequences of collection PC96082 are very similar to the sequences of I. bulbomarginata that we infer to be of the same species. Inosperma flavobrunneum is nested in Old World Tropical clade 1 as sister species to three undescribed collections, BB3233, G1842 and PC96013, all from Zambia with weak support.

Taxonomy

Inosperma africanum Aïgnon, Yorou & Ryberg, sp. nov.

MycoBank No: 836199
Figs 2a, 3

Diagnosis

Inosperma africanum is distinct from all species of Inosperma and truly outstanding by its vinaceous to red colouration.

Type

Holotype. Benin, Collines Region, Kilibo: 8°32.74'N, 2°40.42'E, on soil in Forest Reserve of Toui-Kilibo in Woodland dominated by Isoberlina doka and I. tomentosa, 11 August 2017, leg. AIGNON L.H, Voucher (HLA0383) GenBank accession: ITS (MN096193); LSU (MN097885) and RPB2 (MT770739).

Description

Pileus 8.5–15 mm diam., convex to plane, uniform, surface fibrillose, vinaceous to red (8F8), surface rimose, dry. Lamellae moderately close, subventricose, narrowly attached, 0.5–1 mm deep; vinaceous, sometimes light pinkish (8F8), edges fimbriate, vinaceous (8B8). Stipe 15–23 × 0.5–1 mm, cylindrical, central, fibrillose, swollen, bulbous at the base, veil none with the lower two thirds pinkish-white (8A3) and the upper third light vinaceous (8A5). Odour and taste not distinctive. Basidiospores (6.2) 8–10 (10.3) × (3.8) 4–6.8 (7) μm, avl × avw = 8.3 × 5.3 μm, Q = (1.2) 1.1–2.1 (2.2), avQ = 1.6, smooth, (sub) globose to cylindrical, sometimes ellipsoid. Basidia 18–47 × 7–10 μm, clavate, 3–4 sterigmate, hyaline. Cheilocystidia 22–54 × 8–12 μm, cylindrical to clavate, thin-walled, hyaline. Pleurocystidia absent. Pileipellis a cutis with cylindrical, smooth, thin-walled hyphae, 6–20 μm diam., negative reaction of pileus surface in KOH. Stipitipellis a cutis radially arranged, hyphae 5–13 μm diam., parallel, sometimes septate, filamentous. Caulocystidia 22–63 × 8–13 μm, fusiform sometimes utriform, observed on the upper third of the stipe. Clamp connections present.

Distribution

Currently known from Benin, Burkina Faso, Guinea, Ivory Coast, Togo.

Ecology

Scattered in Tropical Woodlands dominated by Isoberlinia doka and I. tomentosa or gallery forests dominated by Berlina grandiflora.

Etymology

africanum, referring to the distribution in Africa.

Additional specimens examined

Benin, Borgou Province, N’dali Region: 8°32.74'N, 2°40.42'E, on soil in Woodland dominated by Isoberlina doka, 30 August 2017 in Forest Reserve of N’dali, Leg. Aïgnon HL., Voucher (HLA0461) GenBank accession: ITS (MT534297) and LSU (MT560732). Benin, Borgou Province, Tchaorou Region: 9°15.28'N, 2°43.38'E, on soil in forest of Okpara in woodland dominated by I. doka, 7 June 2017, leg. Aïgnon HL., Voucher (HLA0353) GenBank accession: ITS (MT534299). Benin, Borgou Province, N’dali Region: 8°45.73'N, 2°19.93'E, on soil in Woodland dominated by Isoberlina doka, 8 July 2013, leg. Ryberg M., Voucher (MR00361). Benin, Province, Boukoumbe, North Region: 10°14.45'N, 1°7.00'E, on soil in Woodland dominated by Isoberlina doka, 25 July 2020 in Koussoukouangou waterfall, Leg. Aïgnon HL., Voucher (HLA0736). Burkina Faso, Kenedougou Province, Toussiambandougou Region: 10°55.86'N, 4°51.83'W, on soil in gallery forest dominated by Berlina grandiflora, 27 June 2018, leg. Aïgnon HL., Voucher (HLA0353). Ivory Coast, Kekrekouakoukro Province, Bouake, Gbeke Region: 7°40.52'N, 4°54.48'W, on soil in Woodland dominated by B. grandiflora, 11 July 2018, leg. Aïgnon HL., Voucher (HLA0562). Guinea, Faranah Province, Upper Guinea Region, National Park of Haut Niger: 10°30.76'N, 9°57.68'W, on soil in Woodland dominated by B. grandiflora, 4 July 2018, leg. Aïgnon HL., Voucher (HLA0532). Togo, Central Region, Prefecture of Assoli, on the road between Bafilo and Aledjo: 09°20.38'N, 1°14.44'E in Woodlands dominated by I. tomentosa, 7 August 2013, leg. Martin Ryberg, Voucher (MR00387) GenBank accession: ITS (MN096189); LSU (MN097881), RPB2 (MT770739).

Notes

Inosperma africanum is nested in Inosperma and indicated as sister to the rest of the genus in our phylogenetic analyses and is very distinct by its small size and a vinaceous to red pileus. It has a wide distribution in West Africa.

Inosperma bulbomarginatum Aïgnon, Yorou & Ryberg, sp. nov.

MycoBank No: 836198
Figs 2b, 4

Diagnosis

Inosperma bulbomarginatum differs from I. flavobrunneum by the smaller size of its basidiomata and larger basidiospores. It is phylogenetically distinct from all other undescribed African Inosperma in Old World Tropical clade 2

Type

Holotype. Benin, Borgou Province, N’dali Region: 09°45.73'N, 2°19.93'E, on soil in Woodland dominated by Isoberlina doka and I. tomentosa, 8 July 2013, leg. Martin Ryberg, Voucher (MR00357), GenBank accession: ITS (MN096190); LSU (MN097882) and RPB2 (MN200775).

Description

Pileus 13–18 mm diam., undulating plane, fibrillose, margin rimose, orange-brown to somewhat cinnamon, greyish-white (8E5), splitting at edge. Lamellae 2–2.5 mm deep, moderately close, narrowly attached, pale grey brown (9B5) to dark brown (9D5), sinuate. Stipe 10–22 × 2–2.5 mm, central, equal, marginate bulb, white to pinkish-buff (7A2), velar remnants. Odour and taste not distinctive. Basidiospores (7.1) 8–12.1 (14) × (4) 4.2–6.7(7) μm, avl × avw = 9.6 × 5.4 μm, Q = (1.3) 1.2–2.3(2.6), avQ = 1.8, smooth, elongate, thick-walled. Basidia (25) 28–40 × 6–12 μm, tetrasporic. Cheilocystidia 20–25 × 10–12 μm, clavate, thin-walled hyaline. Pleurocystidia absent. Pileipellis a cutis, thin-walled hyphae, 3–12 μm diam., cylindrical. Stipitipellis a cutis with subparallel hyphae 3–15 μm diam., septate, filamentous, subhymenium of compact hyphae, any reaction of pileus surface in KOH not observed. Caulocystidia 25–60 × 7–20 μm, ovoid to obovoid, sometimes utriform, observed on the upper third of the stipe.

Distribution

Currently known from Benin and Zambia.

Ecology

Scattered in Woodland dominated by Isoberlinia doka and I. tomentosa.

Etymology

bulbomarginatum referring to the presence of a marginate bulb at the base of the stipe.

Additional specimens examined

Benin, Collines Province, Kilibo Region: 8°32.74'N, 2°40.42'E, on soil in Woodland dominated by Isoberlina doka, 22 June 2017 in the Forest Reserve of Toui-Kilibo, leg. Aïgnon HL., Voucher (HLA0389) GenBank accession: ITS (MT534302). Benin, Tchaorou, Borgou Prov, Okpara Forest: 9°15.28'N, 2°43.38'E, on soil in Woodland dominated by Isoberlina doka, 13 June 2017, leg. Aïgnon HL., Voucher (HLA0373) GenBank accession: ITS (MT534301). Benin, Alibori Borgou Prov, Alibori Superieur Forest Reserve: 10°23.76'N, 2°5.15'E on soil in Woodland dominated by Isoberlina doka, 11 July 2017, in Forest Reserve of Alibori Supérieur leg. Aïgnon HL., Voucher (HLA0417), GenBank accession: ITS (MT534300) and LSU (MT560734).

Notes

Inosperma bulbomarginatum is similar to Inosperma cervicolor (Pers.) Matheny & Esteve-Rav., by its orange-brown pileus, but differs from it by the smaller size of the basidiomata and basidiospores, as well as its ecological association with Fabaceae Lindley and/or Phyllanthaceae Martynov and extensive distribution in Tropical Africa. I. cervicolor is associated with Pinaceae Spreng. ex F. Rudolphi and distributed in Europe and North America.

Inosperma flavobrunneum Aïgnon, Yorou & Ryberg, sp. nov.

MycoBank No: 836197
Figs 2c, d, 5

Diagnosis

Characterised by yellow to orange-brown pileus, 7–12 × 4–7 μm smooth, thick-walled, ellipsoid basidiospores with cheilocystidia measuring 23–41 × 7–10 μm, clavate, thin-walled.

Type

Holotype. Benin, Borgou Province, Tchaorou, Okpara Forest: 9°15.13'N, 2°43.05'E on soil in Woodland dominated by Isoberlina doka 12 June 2017, leg. AIGNON L.H, Voucher (HLA0367), GenBank accession: ITS (MN096199); LSU (MT536754).

Description

Pileus 28–38 mm diam., umbonate, yellow (5A3) to orange brown (5C5), dark brown in middle, convex when young, plane at maturity, hard, surface rimose, dry. Lamellae emarginated, adnexed and decurrent, yellow brown (5B5). Stipe 27–39 × 5–6 mm, central, cylindrical, uniform; white, equal, solid, hard, base slightly swollen to bulbous, pruinose at the apex. Basidiospores (7.1) 9.2–11.2 (12) × (4.1) 5.7–7 (7.2) μm, avl × avw = 9.2 × 5.7 μm, Q = (1.2) 1.6–2.1 (2.5), avQ = 1.6, smooth, ellipsoid. Basidia 24–40 × 6–14 μm, clavate, 2–4 spored. Cheilocystidia 23–41 × 7–10 μm, clavate, thin walled. Pleurocystidia absent. Pileipellis a cutis thin-walled hyphae 4–16 μm diam., subparallel, compact hyphae, negative reaction of pileus surface in KOH. Stipitipellis a cutis hyphae 5–10 μm diam., septate, filamentous, thick, subparallel, compact. Caulocystidia 23–52 × 9–10 μm, utriform, rare, observed on the upper third of the stipe.

Distribution

Currently known only from Benin in Soudano-Guinean zone.

Ecology

Gregarious under Woodland dominated by Isoberlinia doka, I. tomentosa and Monotes kerstingii Gilg.

Etymology

flavobrunneum referring to yellow to dark brown pileus.

Additional specimens examined

Benin, Tchaorou, Borgou Province, Okpara Forest: 9°15.27'N, 2°43.40'E on soil in Woodland dominated by Isoberlina doka, I. tomentosa 13 June 2017, leg. AIGNON L.H, HLA0372, GenBank accession: ITS (MT534290); LSU (MT536756).

Notes

In the phylogenetic tree (Figure 1), Inosperma flavobrunneum is a sister of Inosperma sp. PC96013, an undescribed species from Zambia in Miombo woodland. Morphologically, I. flavobrunneum is similar to I. lanatodiscum by its yellow to orange-brown pileus, but differs from it by the smaller size of the basidiomata, larger basidiospores, ecological association with Fabaceae / Dipterocarpaceae Blume and distribution in West Africa. I. lanatodiscum is associated with a variety of hardwoods and conifers and is widely distributed from Europe to North and Central America (Kropp et al. 2013). The other related taxa are all African taxa not yet described, such as Inosperma sp. BB3233 from Zambia and the Democratic Republic of Congo, as well as Inosperma sp. G1842 distributed in south-eastern Africa, while I. flavobrunneum is distributed in West Africa.

Figure 1. 

ML tree of 28S and RPB2 sequences showing the placement of Inosperma africanum, I. bulbomarginatum and I. flavobrunneum. Values above or below branches indicate bootstrap proportions SH-aLRT support ≥ 80% / ultrafast bootstrap support ≥ 95% / Bayesian posterior probabilities > 0.95 as shown. Origin of species is given after the name of each taxon. The new species are in red.

Figure 2. 

Macromorphology of: A Inosperma africanum (HLA0383) B Inosperma bulbomarginatum (MR00357) C, D Inosperma flavobrunneum (HLA0367). Scale bar: 1 cm.

Figure 3. 

Microscopic structures of Inosperma africanum (HLA0383) A basidiospores B basidia C cheilocystidia D caulocystidia E pileipellis F stipitipellis. Scale bars: 3 μm (A); 5 μm (B); 10 μm (C–F).

Figure 4. 

Microscopic structures of Inosperma bulbomarginatum (MR00357) A basidiospores B basidia C cheilocystidia D caulocystidia E pileipellis F stipitipellis. Scale bars: 3 μm (A); 5 μm (B); 10 μm (C–F).

Figure 5. 

Microscopic structures of Inosperma flavobrunneum (HLA0367) A basidiospores B basidia C cheilocystidia D caulocystidia E pileipellis and F stipitipellis. Scale bars: 3 μm(A); 4 μm (B); 10 μm (C–F).

Taxonomic key to species of Inosperma from West Africa

1 Basidiomata large, pileus 28–38 mm diam., yellow to orange-brown, surface clearly rimose, lamellae adnexed and decurrent, subdistant Inosperma flavobrunneum
Basidiomata small, pileus 8.5–15 mm diam., fibrillose, lamellae close 2
2 Pileus vinaceous to red, basidiospores 8–10 × 4–7, (sub) globose to cylindrical, sometimes ellipsoid I. africanum
Pileus orange-brown to somewhat cinnamon, greyish-white, basidiospores 8–14 × 4–7 μm, elongate I. bulbomarginatum

New combination

For an evolutionarily-consistent taxonomy, we propose the following combination:

Inosperma shawarense (Naseer & Khalid) Aïgnon & Naseer, comb. nov.

MycoBank No: 836296

Inocybe shawarensis Naseer & Khalid, Mycotaxon 132: 912. 2018. Basionym.

Notes

This species is placed in the old Inosperma clade which became the genus Inosperma, but the combination is not made in the study of Matheny et al. (2020). The new combination is based on molecular phylogenetic data and sequencing the type of Inocybe shawarensis (Naseer et al. 2018).

Discussion

The new species exhibit the overall characteristics often observed in Inosperma. These characters include; pileus radially rimose, fibrillose or squamulose and absence of pleurocystidia (Matheny et al. 2020). They can be distinguished from other Inosperma species by their remarkable characteristics. In addition, I. africanum is common in West Africa and I. bulbomarginatum presents a large distribution and was recognised in Zambia in the collections of Bart Buyck (Matheny et al. 2009). However, the low sequence divergences between the sequences (2.2%–2.5%) of ITS and 0.3% of 28S allows us to confirm the wide distribution of I. bulbomarginatum.

Phylogenetically, I. africanum is nested in Inosperma with full support (99% SH-aLRT values, 100% ML Ultrafast bootstrap, 1 BPP) and I. bulbomarginatum is indicated as the sister of Old World Tropical clade 1 with full support (100% SH-aLRT values, 100% ML bootstrap, 1 BPP). Sequences of Inosperma bulbomarginatum from West Africa and Zambia formed a subclade. Inosperma flavobrunneum is nested in Old World Tropical clade 1 and has sister species undescribed in a collection from Zambia, BB3233, G1842 and PC96013. ML and BI analysis, using 28S and RPB2 sequences data, shows most nodes well resolved; for example, the node uniting Old World Tropical clade 2 with the crown group of Inosperma is supported with 0.97 BPP, but with weak ML bootstrap as shown in Pradeep et al. (2016); based also on combined data of 28S and RPB2, this node is with weaker support < 50% ML bootstrap.

The position of each of these new species is confirmed by single data from ITS (Fig. 6). There are several collections from undescribed species in Inosperma (e.g. Inosperma sp. G1842, Inosperma sp. BB3233, Inosperma sp. PC 96073, Inosperma sp. PC96013, Inosperma sp. PC96082, Inosperma sp. PC96080 and Inosperma sp. Zam07) that are of African origin, thereby attesting the need for further studies of this genus on this continent. Previously, in Inosperma, only one species, Inosperma misakaense, has been described from Africa before this study (Matheny and Watling 2004). So, this study reinforces the diversity of Inosperma in Tropical Africa which now amounts to four described species.

Figure 6. 

ML phylogeny of Inosperma africanum, I. bulbomarginatum and I. flavobrunneum based on ITS dataset.

Acknowledgements

We are grateful to the Rufford Small Grants Foundation (grant n° 30738-2) which allowed us to collect some additional samples analysed in this paper, the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (grant n° 226-2014-1109) for funding molecular analysis and the Deutscher Akademischer Austauschdienst (DAAD, grant n° PKZ 300499) for granting the University of Parakou with a microscope, type Leica DM5700, that enabled us to perform microscopic investigations. Anneli SVANHOLM, Bobby SULISTYO and Brandan FURNEAUX (Systematic Biology programme, Department of Organismal Biology, Uppsala University) are thanked for their assistance during molecular analyses. We also thank Kassim TCHAN ISSIFFOU and Evans CODJIA (MyTIPS Research Unit, University of Parakou) for their assistance during field data collection. P. Brandon MATHENY (Department of Ecology and Evolutionary Biology, University of Tennessee, USA) and an anonymous reviewer are thanked for their corrections and suggestions to improve our paper.

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Supplementary material

Supplementary material 1 

Partition for phylogeny analysis

Hyppolite L. Aïgnon, Sana Jabeen, Arooj Naseer, Nourou S. Yorou, Martin Ryberg

Data type: phylogeny data

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.
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