Marasmius auranticapitatus J.S. Oliveira, 2022

S, Jadson José, Oliveira, ouza de, Capelari, Marina, Margaritescu, Simona & Moncalvo, Jean-Marc, 2022, Disentangling cryptic species in the Marasmius haematocephalus (Mont.) Fr. and M. siccus (Schwein.) Fr. species complexes (Agaricales, Basidiomycota), Cryptogamie, Mycologie 20 (5), pp. 91-137 : 106-108

Marasmius auranticapitatus J.S. Oliveira , sp. nov.

( Figs 9A ; 10 )

Differs from M. haematocephalus by having pale orange pileus and slightly larger basidiospores (xmm = 21.1 [± 0.7] × 3.8 [± 0.3] µm, Qmm = 5.7 [± 0.5] vs xmm = 20.5 [± 0.3] × 3.9 [± 0.2] µm, Qmm = 5.2 [± 0.1]); and more distinctly larger than those of the rose or pale red piliated M. rubicundus (xmm = 21.1 [± 0.7] × 3.8 [± 0.3] µm, Qmm = 5.7 [± 0.5] vs xmm = 18.9 [± 0.5] × 3.8 [± 0.1] µm, Qmm = 5 [± 0.2]).

HOLOTYPE. — Brazil. São Paulo State, Santo André City, Reserva Biológica de Paranapiacaba , 2.XII.2009, M. Capelari & L.A.S. Ramos 4554 (holo-, SP[SP 445584]!).

ADDITIONAL EXAMINED MATERIAL. — Brazil. São Paulo State, Santo André City, Reserva Biológica de Paranapiacaba, 16.III.2010, J.J.S. Oliveira JO42 (SP[SP 445408]!); 15.X.2010, J.J.S.Oliveira & C.L.A. Pires JO224 (SP[SP 445445]!); 16.X.2010, J.J.S. Oliveira & C.L.A. Pires JO226 (SP[SP 445446]!); 7.XI.2010, J.J.S.Oliveira & A. V. Costa JO276 (SP[SP 445460]!): J.J.S. Oliveira & A. V. Costa JO277 (SP[SP 445461]!); J.J.S. Oliveira & A. V. Costa JO279 (SP[SP 445463]!); 7.XII.2010, J.J.S. Oliveira, A. V. Costa & P.O. Ventura JO282 (SP[SP 445465]!); J.J.S. Oliveira & P.O. Ventura JO300 (SP[SP 445479]!).

ETYMOLOGY. — Based on the orange pileus.

MYCOBANK. — MB 842535.

HABIT AND SUBSTRATE. — Marasmioid ( Figs 9A ; 10A ), dispersed to gregarious on dead eudicotyledonous leaves in the forest litter.

DESCRIPTION

Pileus

2.4-19 mm diam.( Figs 9A ; 10A ), initially conical, then campanulate or hemispherical, sulcate, sometimes deeply sulcate, center flat or slightly umbonate, wrinkled when dried, margin decurved, edge entire; when young deep reddish orange (N 10 Y 80 M 30 to N 10 Y 99 M 60, N 40 Y 70 M 70), with center dark orange (N 10 Y 99 M 70), becoming yellowish orange or pale orange (N 00 Y 80 M 30, N 10 Y 99 M 50 to N 20 Y 60 M 50) when mature, sometimes with beige hue (N 00 Y 40-60 M 20-40 to N 10 Y 50 M 50-60) or ferruginous orange (N 20 Y 99 M 60) to reddish brown (N 20 Y 50 M 50) when dried, keeping the same pigmentation at the center or becoming chestnut orange (N 30 Y 99 M 50-70, N 40 Y 99 M 80 or N 50 Y 99 M 70); membranous, context thin (<1 mm); glabrous, dry, dull, subvelutinous, non-hygrophanous.

Lamellae ( Fig. 9A )

Free, subfree to narrowly adnate, subdistant to distant, L = 9-14, equal, simple, rarely biforked or intervenose, l = 0, smooth, pale cream (N 00 Y 10 M 00), edge even, non-marginate, interlamellar hymenium concolorous with the lamellae faces.

Stipe ( Figs 9A ; 10A )

9-56 × 0.3-0.8 mm, central, filiform, thin, equal, regular, with circular caliber, chitinous, flexible, hollow, apex whitish pink (N 00 Y M 20-60) to pale orange, becoming orange or amber brown (N 40 Y 60 M 50) to brown or dark brown (N 70 Y 99 M 60) toward the base, glabrous, smooth, with a silky bright; with a scarce, cream, tomentose basal mycelium.

10-40

Odor

Not distinctive.

Basidiospores ( Fig. 10B )

17.1-24.8 × 2.8-5 µm (xrm = 19.4-22.3 × 3.5-4.2 µm; xmm = 21.1 [± 0.7] × 3.8 [± 0.3] µm; Qrm = 5.1-6.3; Qmm = 5.7 [± 0.5], n / s = 30/8), exceptional spore size of JO226 with 17-21.9 × 3-4.2(-5) µm (xm = 19.4 [± 1.0] × 3.6 [± 0.4] µm; Qm = 5.4 [± 0.7]; n / s = 30, s = 1), oblong, subclavate to fusoid, smooth, hyaline, thin-walled, inamyloid.

Basidia

Observed in JO279, 20.1-30.4 × 6-7.6 µm, clavate, hyaline, thin-walled, inamyloid, 4-sterigmate, sterigmata coarse or broad, with obtuse apex.

Basidioles ( Fig. 10C )

21.3-28.8 × 6-8.8 µm, clavate, hyaline, thin-walled, inamyloid.

Pleurocystidia ( Fig. 10D )

(15.1-)22.3-74.3 × 5.2-12.1 µm, clavate, with tapered apex, subacuminate, vesiculose, capitate or papillate, sublageniform, hyaline, thin-walled, refractive.

Cheilocystidia ( Fig. 10E )

Similar to the Siccus-type broom cells of the pileipellis; main body (10-)15-18.8 × 5.6-11.3 µm, clavate to turbinate, hyaline, thin-walled; setulae apical, erect, 2.5-7.5 × 0.8-1.8 µm, cylindrical, regular in outline, solid, apex acute.

Lamellar trama

Dextrinoid, irregular, interwoven, hyphae cylindrical, 1.6- 10 µm diam., regular in outline, branched, smooth, hyaline, thin-walled.

Pileus trama

Similar to the lamellar trama, hyphae 2-6.3 µm diam.

Pileipellis

Hymeniform, composed of Siccus-type broom cells ( Fig. 10F ), abundant, pale yellow when grouped; main body 9.4- 18.8 × 7-10.6 µm, clavate to frequently turbinate, sometimes inflated, or irregular in outline, hyaline,thin-walled, weakly dextrinoid; setulae apical, erect, 3.8-7.5 × 0.6-1.3 µm, filiform,thin, regular in outline, sometimes branched,solid,hyaline, apex acute.

Stipe trama

Dextrinoid, cortical hyphae parallel, 3-13.8 µm diam., cylindrical, regular in outline, rarely branched, smooth, pale brown, thick-walled; internal hyphae 2.5-7.5 µm diam., hyaline, thin-walled.

Clamp connections

Present in all tissues.

REMARKS

Marasmius auranticapitatus J.S. Oliveira , sp. nov. is very similar to M. haematocephalus (blood red pileus) but has more pale yellowish orange pileus (reddish when young) and slightly longer basidiospores (xmm = 21.1 [± 0.7] × 3.8 [± 0.3] µm, Qmm = 5.7 [± 0.5] vs xmm = 20.4 [± 0.3] × 3.9 [± 0.1] µm, Qmm = 5.3 [± 0.1]). Yet, the ranges of the basidiospores sizes are largely overlapping. Marasmius auranticapitatus J.S. Oliveira , sp. nov. is 0.2-1 % dissimilar to M. haematocephalus based on the nrITS and 0.6-1 % dissimilar on the nrLSU.However, M. auranticapitatus J.S. Oliveira , sp. nov. is closer and sister to M. rubicundus (Singer) J.S. Oliveira , stat. nov. ( Figs4 ; 5 ). Based on the nrITS data, M. auranticapitatus J.S. Oliveira , sp. nov. is 0.7-1.7% dissimilar to M. rubicundus (Singer) J.S. Oliveira , stat. nov., 0.2-0.6 % dissimilar in the nrLSU, 4.7-5.2% dissimilar in the rpb 2 and 1.4-1.9 dissimilar in the ef 1 - α. Marasmius auranticapitatus J.S. Oliveira , sp. nov. differs from M. rubicundus (Singer) J.S. Oliveira , stat. nov. in the pale yellowish orange pileus (vs rose, pink or pale red) and longer basidiospores (xmm = 21.1 [± 0.7] × 3.8 [± 0.3] µm, Qmm = 5.7 [± 0.5] vs xmm = 18.9 [± 0.5] × 3.8 [± 0.1] µm, Qmm = 5 [± 0.2]). With a transitional/ intermediate pattern and possibly a hydrid, the exceptional spore sizes of JO226 (more compatible with M. rubicundus (Singer) J.S. Oliveira , stat. nov.) strengthens the plausibility of the most recent common ancestry between M. auranticapitatus J.S. Oliveira , sp. nov. and M. rubicundus (Singer) J.S. Oliveira , stat. nov., a bridge of intercompatibility and gene flow or an ancestry trace. QuotingTaylor et al. (2000): “Even when BSR (Biological Species Recognition) can be applied to fungi, there is evidence that the criterion of reproduction lumps together groups of fungi that are genetically isolated in nature, but that retain the ancestral character of interbreeding”.

Marasmius auranticapitatus J.S. Oliveira , sp. nov. is similar to M. siccus in the pileus pigmentation. However, based on the holotype, M. siccus has smaller basidiospores 15.2- 20 × 3.2-4.6 µm ( Desjardin 1989). Also, M. siccus s.l. has more robust basidiomata ( Gilliam 1976; Noordeloos 1987; Antonín & Noordeloos 2010; Antonín et al. 2012;) and temperate distribution. In the phylogenetic trees (Fig. 1), M. auranticapitatus J.S. Oliveira , sp. nov. is close to M. haematocephalus (embedded in haemat_cp1) and distant from M. siccus . Marasmius auranticapitatus J.S. Oliveira , sp. nov. is part of the haemat_cp2a ( Fig. 3 ), only fully resolved in Figure 5 . Marasmius haematocephalus var. anomaloides Desjardin originally described from the Tennessee, United States, also has orange pileus but differs from M. auranticapitatus J.S. Oliveira , sp. nov. in having much shorter basidiospores (14.4-19.2 × 3.4-4.6µm) ( Desjardin 1991). The new species is neighter similar to any of the varieties of M. haematocephalus in Singer (1976) nor to any of the heterotypic sysnonyms once listed under M. haematocephalus (Appendix) .

Figures

FIG. 9. — Pictures of fresh basidiomata: A, Marasmius auranticapitatus J.S. Oliveira, sp. nov. (M. Capelari & L.A.S. Ramos 4554); B, M. castanocephalus J.S. Oliveira, sp. nov. (JO523); C, M. coasiaticus J.S. Oliveira, sp. nov. (JO323). Scale bars: 10 mm.

FIG. 10. — Marasmius auranticapitatus J.S. Oliveira,sp.nov. (M. Capelari & L.A.S. Ramos 4554): A, basidiomata;B, basidiospores;C, basidioles;D, pleurocystidia; E, cheilocystidia; F, Siccus-type broom cells of the pileipellis. Scale bar: A, 10 mm; B-F, 10 µm.

FIG. 4. — Best-scored Maximum Likelihood tree (left side, TL = 0.054576) and 50% majority-rule consensus tree (right side, TL = 4.954404) of Bayesian analyses built from multilocus (nrLSU and nrITS) analyses (DATASET 3) of the haemat_cp2a (Fig. 3). Black, thick stems indicate high support and gray, thick stems indicate weak to moderate support. Dark red shade indicates M. haematocephalus (Mont.) Fr., the orange shade indicates M. auranticapitatus J.S. Oliveira, sp. nov. and the pink shade indicates M. rubicundus (Singer) J.S. Oliveira, stat. nov.

FIG. 5. — Best-scored Maximum Likelihood trees (left side,TL = 0.111755;0.135069) and 50% majority-rule consensus trees (right side, TL = 0.106492;0.120539) of Bayesian analyses built from multilocus (nrITS + rpb2 + ef1-α) analyses (DATASET 4) of the haemat_cp2a (Fig. 3). Black, thick stems indicate high support and gray, thick stems indicate weak to moderate support. Orange shade indicates M. auranticapitatus J.S. Oliveira, sp. nov. and the pink shade indicates M. rubicundus (Singer) J.S. Oliveira, stat. nov. Trees on the top includes MC4554 (holotype of M. auranticapitatus J.S. Oliveira, sp. nov.).

FIG. 3. — Best-scored Maximum Likelihood Tree (TL = 0.555713) built from multilocus (nrITS and nrLSU) analysis based on haemat_cp1 in Fig. 1 (DATASET 2b). Support values are BS (70 to 100 %) and PP (0.95 to 1.0). Black, thick stems indicate high support and gray, thick stems indicate weak to moderate support. The gray shades highlight the haemat_cp2a-e and the cryptic species in red rectangles if pileus color is a determinant constrain. Red arrows indicate the geographic origin of strains in the tree. Global map is based on Olson & Dinerstein (2002) with forested areas depicted in their biogeographic realms.