Marasmius magnus A.C. Magnago & J.S. Oliveira, 2016
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publication ID |
https://doi.org/ 10.11646/phytotaxa.266.4.4 |
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persistent identifier |
https://treatment.plazi.org/id/AC228797-6E6B-FF84-FC90-FD65FD6B9BC2 |
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treatment provided by |
Felipe |
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scientific name |
Marasmius magnus A.C. Magnago & J.S. Oliveira |
| status |
sp. nov. |
Marasmius magnus A.C. Magnago & J.S. Oliveira View in CoL , sp. nov. Figs. 1–2 View FIGURE 1 View FIGURE 2 .
MycoBank:—MB 816824
Diagnosis:—Pileus large (31–122 mm diam.), fulvous to rusty orange, center reddish brown, with cream margin. Lamellae free to adnexed, 18–22 per cap. Stipe 70–94 × 4–6 mm, light reddish brown. Basidiospores (4.8–)5.2–8.8 × 2.5–3.8 μm. Pleurocystidia 30–87.5 × 5–7.5 μm, rarely projecting. Cheilocystidia absent. Pileipellis composed of Siccus - type broom cells. Caulocystidia cylindrical to bilobed.
Type:— BRAZIL. Santa Catarina: Florianópolis, Morro da Lagoa, Trilha do Jipe, growing on decomposing leaf litter in Atlantic Forest, 27°35’04.5”S, 48°28’29.0”, 20 March 2014, Magnago AC 1001 (FLOR 55963!). GenBank accession: ITS = KX228846.
Etymology:—from Latin magnus (large, great); referring to the large size of the basidiomata.
Description: —Pileus 31–122 mm wide, paraboloid when young, broadly convex to nearly plane when mature, dry, glabrous to velutinous in the center, opaque, slightly sulcate towards the margin, fulvous to rusty orange (OAC 642), center reddish brown (OAC 656), extreme margin generally whitish cream. Lamellae free to adnexed, not collariate, 18–22 per cap, centrally broad, 5–13 mm wide, whitish to creamy buff (OAC 815), entire, not intervenose, distant;
lamellulae present, in 4–5 series. Stipe 70–94 mm long, 4–6 mm thick, cylindrical, equal, cartilaginous to fibrous, hollow, glabrous to slightly pruinose, light reddish brown (OAC 728); with whitish, tomentose basal mycelium.
Basidiospores (4.8–)5.2–8.8 × 2.5–3.8 μm [X rm = 6.3–7 × 3–3.2 μm, X mm = 6.6 (± 0.4) × 6.6 (± 0.1), Q rm = 2–2.3, Q mm = 2.1 (± 0.2), n/s = 30, s = 3], ellipsoid to cylindrical, lacrimoid to short bacilliform, smooth, thin-walled, hyaline, inamyloid. Mature basidia not observed, basidioles 21–35 × 4–8 μm, clavate, hyaline. Cheilocystidia absent. Pleurocystidia 30–87.5 × 5–7.5 μm, rarely projecting over the top of the basidioles, originating deep in the subhymenium, scattered or rare, cylindrical to narrowly fusiform, apex rounded, occasionally subcapitate, hyaline,
inamyloid. Lamellae trama loosely interwoven, hyphae 6–17 μm wide, cylindrical, hyaline, strongly dextrinoid.
Pileipellis hymeniform, composed of Siccus - type broom cells, thick-walled; main body 17–28 × 6–9 μm, clavate to pyriform, ochraceous, yellowish brown to hyaline in KOH; setulae 4–21 μm long, 1.5–3 μm wide at base, rounded obtuse to tapered or acute at apex, erect, yellowish brown, dextrinoid. Stipitipellis composed of hyphae 2–3 μm wide,
cylindrical, pale yellow, caulocystidia cylindrical to forked or bilobed, 22–18 × 4–5 μm, hyaline. Stipe trama composed of hyphae in parallel, 5–8 μm wide, cylindrical, hyaline, dextrinoid. Hyphae at stipe base 1–2 μm wide, cylindrical,
hyaline, dextrinoid. Clamp connections present.
Habit and habitat:—Gymnopoid habit, growing gregarious on leaf litter in coastal Atlantic Forest.
Specimens examined:— BRAZIL. Santa Catarina, Florianópolis, Morro da Lagoa , Trilha do Jipe , 20 March 2014, Magnago AC 1001 (holotype FLOR 55963 About FLOR !; isotype SP!), Magnago AC 1002 ( ICN 179251 View Materials !) ; 16 March 2011, Jaeger M 048 ( FLOR 55928 About FLOR !), Trilha da Lagoa do Peri, 09 February 2015, Neves MA & Smith NP 1155 ( FLOR 55930 About FLOR !), 13 February 2015, Smith NP 514 ( FLOR 55929 About FLOR !), Trilha para praia de Naufragados , 12 October 2015, Neves MA & Smith NP 1165 ( FLOR 55830 About FLOR !). Rio Grande do Sul, Porto Alegre, Morro Santana, 12 January 2015, Magnago AC 1128 ( ICN 179252 View Materials !) .
Phylogenetic analyses
The final matrix of the dataset consisted of 86 sequences from 52 taxa ( Table 1) forming an alignment of 552 base pairs length with 291 unique site patterns, having only unambiguous blocks. The mean of the values from the runs of MC 3 were: estimated marginal likelihood = -3875.33 (mean of the values of the two runs), Tree-Length (TL) = 10.980430, alpha = 0.228992, pinvar = 0.398595, rates A <=> C (0.089483), A <=> G (0.373243), A <=> T (0.093071), C <=> G (0.011757), C <=> T (0.394959), G <=> T (0.037488), frequencies pi(A): 0.249541, pi(C): 0.196779, pi(G): 0.209575, pi(T): 0.344104. For ML, the final ML Optimization Likelihood was -3722.361136; model parameters were: alpha = 0.208880, TL = 1.686086, rates A <=> C (2.133641), A <=> G (7.281515), A <=> T (2.225075), C <=> G (0.259901), C <=> T (8.856011), G <=> T (1.000000), frequencies pi(A): 0.241344, pi(C): 0.206181, pi(G): 0.221598, pi(T): 0.330877.
The 50 % majority-rule consensus tree from B is shown in Figure 3 View FIGURE 3 . The tree is divided into two clades: / Globulares and /Outgroup, both with high statistical support (posterior probability (PP) 1.0 and ML Bootstrap (BS) 99). / Globulares is the ingroup of taxa members of sect. Globulares sensu Antonín & Noordeloos (2010), with all traditional groups represented. The ITS data were informative enough to solve and provide high support for nearly all terminal nodes (species level, or a little bit higher), but many intermediary and all deep nodes are unsupported as expected. The ingroup seems to present three groups of correlated taxa that are not entirely defined by ITS. Marasmius magnus , represented by five samples, clustered within a distinct but unsupported subclade, which is the earliest diverging lineage within / Globulares (depicted by a gradient grey squared shade). The highly supported branch bearing the new species (PP 1.0 and BS 100) rises from an unsupported node revealing it sister with a branch bearing M. nivicola Har. Takah. , M. maximus Hongo and M. wynneae Berk. & Broome. Moreover , this subclade is poorly resolved, with three more branches rising from a collapsed edge. The best-scoring ML tree (Supplementary Material) presented correspondent topology, with no conflict with the Bayesian tree.
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