Marasmius coasiaticus J. S. Oliveira 2022, sp. nov.
Creators: name: S, Jadson José
name: Oliveira, ouza de
name: Capelari, Marina
name: Margaritescu, Simona
name: Moncalvo, Jean-Marc
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Marasmiaceae
Marasmius
Marasmius coasiaticus

description: Marasmius coasiaticus J.S. Oliveira, sp. nov.
(Figs 9C; 12)
Differs from Marasmius asiaticus Mesic & Tkalcec (synonym: M.distantifolius Y.S. Tan & Desjardin) in not having violet or ruby nor bright pink pileus which is rather larger (3.5-17 mm diam. vs 2-8 mm diam.), in having more numerous (10-12) non-marginate lamellae, in having smaller basidiospores (13.8-20 × 3.3-4.4 µm vs 18.5-23[-25] × 3.5-5[-6] µm), in having shorter and especially broader pleurocystidia (35-51.3 × 12-18.8 µm vs 37-42 × 9-12 µm), and in having non-mottled pileipellis.
HOLOTYPE. — Brazil. São Paulo State, Santo André City, Reserva Biológica de Paranapiacaba, 9.XII.2010, J.J.S. Oliveira, P.O.Ventura & A. V. Costa JO 323 (holo-, SP[SP 445491]!).
ADDITIONAL MATERIAL EXAMINED. — Brazil. São Paulo State, São Paulo City, Parque Estadual das Fontes do Ipiranga, 1.III.2011, J.J.S. Oliveira & F. Karstedt JO339 (SP[SP 445502]!).
ETYMOLOGY. — Due to its close relationship as sister to M. asiaticus, in the Tropical Asia.
MYCOBANK. — MB 842537.
HABIT AND SUBSTRATE. — Marasmioid (Figs 9C; 12A), gregarious, on dried eudicotyledonous leaves and twigs in the forest litter.
DESCRIPTION
Pileus (Figs 9C; 12A)
3.5-17 mm diam., hemispheric to convex, becoming plane, slightly sulcate, center flat or with a shallow depression, margin decurved to straight, edge entire to slightly crenate; mostly brownish red (N 60 Y 70 M 90), sometimes brownish pink (N 40 Y 60 M 60-70) or orangish red (N 50 Y 80 M 70), with dark reddish brown center (N 80 Y 99 M 80); membranous, context thin (<1 mm); glabrous, dry, dull, subvelutinous, non-hygrophanous.
Lamellae (Figs 9C; 12A)
Adnate, subdistant to distant, L = 10-12, equal, simple or slightly intervenose, l = 0, opaque, cream (N 00 Y 10 M 00), edge even, nonmarginate, interlamellar hymenium concolorous with the pileus.
Stipe (Figs 9C; 12A)
9-20 × 0.3-0.5 mm, central, generally short, curved, filiform, thin, equal, with circular caliber, chitinous, hollow, apex concolorous with the lamellae, becoming black elsewhere, glabrous, smooth, glossy; with a scarce, white to cream, tomentose basal mycelium.
Odor
Not distinctive.
Basidiospores (Fig. 12B)
13.8-20(-20.6) × 3.3-4.4 µm (xmr = 17-18.2 × 3.8-3.9 µm; xmm = 17.6 [± 0.8] × 3.9 [± 0.1] µm; Qrm = 4.4-4.8; Qmm = 4.6 [± 0.3]; n / s = 30/2), oblong, clavate to subfusoid, smooth, hyaline, thin-walled, inamyloid.
Basidia (Fig. 12C)
19.4-25 × 6.6-9 µm, broadly clavate, smooth, hyaline, 2-4-sterigmate, inamyloid, thin-walled.
Basidioles (Fig. 12D)
17.3-22.5 × 7-9.8 µm, broadly clavate, smooth, hyaline, thin-walled, inamyloid.
Pleurocystidia (Fig. 12E)
(16.3-)35-51.3 × 12-18.8 µm, abundant, broadly clavate to inflated, bacilliform, almost oval, smooth, slightly fuscous, yellowish, sometimes hyaline, thin-walled, refractive, inamyloid.
Cheilocystidia (Fig. 12F)
In form of Siccus-type broom cells, hyaline, walls thinner than those of the pileipellis; main body 10-16.3 × 5.6-11.3 µm, cylindrical to clavate, sometimes pyriform to turbinate, thinwalled, hyaline; setulae apical, sometimes slightly divergent, erect, generally short, 1.3-3.8(-5) × 0.6-1 µm, filiform, cylindrical, digitiform, or conical to verruciform, simple or rarely branched, solid, hyaline, regular to slightly irregular in outline, apex obtuse to somewhat acute.
Lamellar trama
Dextrinoid, irregular, interwoven, hyphae cylindrical, 2-6.3 µm diam., regular or irregular in outline, smooth, hyaline, branched and strongly connected, thin-walled.
Pileus trama
Similar to the lamellar trama, hyphae 2-7.5 µm diam.
Pileipellis
Hymeniform, composed of Siccus-type broom cells (Fig.12G), abundant, brownish when in group; main body 11.3-18.8 × 6.3- 16.3 µm, clavate to turbinate, sometimes flattened, or branched, or irregular in outline, hyaline, thin- to somewhat thick-walled; setulae or diverticula apical, sometimes slightly divergent, erect, 0.6-3.8(-5) × 0.5-1.1 µm, cylindrical, digitiform, or verruciform to vesiculose, simple to branched, regular to irregular in outline, almost monilioid, solid, hyaline, or melleus to pale brown, apex obtuse to slightly acute.
Stipe trama
Slightly dextrinoid, cortical hyphae parallel, cylindrical, regular in outline, 2.5-8.8 µm diam., branched, smooth, dark brown, yellowish brown when separated, thick-walled; internal hyphae hyaline, 1.3-11.3 µm diam., thin-walled.
Clamp connections
Present, except in the cortical hyphae of the stipe.
REMARKS
Marasmius coasiaticus J.S. Oliveira, sp. nov. is morphologically very close to M. haematocephalus, but produces smaller, thinner and more delicate basidiomata, having often short and curved stipe. The basidiospores are shorter in average (17-18.2 µm vs 20.1-21 µm) and the pleurocystidia are pale yellow, distinctly broadly clavate or bacilliform inflated (12- 18.8 µm vs 7-9.9 µm in width). Finally, the apical setulae of the Siccus-type broom cells are many times shorter and verruciform. Marasmius coasiaticus J.S. Oliveira, sp. nov. is 1.8 % dissimilar to M. haematocephalus in nrITS. The evident broader pleurocystidia combined with the shorter basidiospores in M. coasiaticus J.S. Oliveira, sp. nov. easily separate it from all varieties under M. haematocephalus (Singer 1976). Marasmius sanguineus Cooke & Massee may be similar, but differs in the adnexed, ventricose, marginate lamellae and longer stipe (up to 40 mm vs up to 20 mm) with lower pileus/stipe length proportion (Cooke 1889; Appendix).
Marasmius coasiaticus J.S. Oliveira, sp. nov. from Brazil is rather sister to M. asiaticus from Malaysia and additional collections from India and Thailand (Figs 1; 3) and, therefore, distant from M. auranticapitatus J.S. Oliveira, sp. nov., M. castanocephalus J.S. Oliveira, sp. nov., M. haematocephalus, M. roseus J.S. Oliveira, sp. nov. and M. rubicundus (Singer) J.S. Oliveira, stat. nov. from Brazil. Marasmius asiaticus was originally named M. distantifolius but, due to competing homonymy with Marasmius distantifolius (Murrill) Murrill, was renamed in Mesic & Tkalcec (2010). Marasmius asiaticus (synonym: M. distantifolius) differs from M. coasiaticus J.S. Oliveira, sp. nov. by having ruby to pinkish hues in the brownish red to brownish violet pileus, marginate, 7-8 lamellae, larger basidiospores (18.5-23[-25] × 3.5-5[-6] µm), smaller pleurocystidia (37-42 × 9-12 µm), and mottled pileipellis (Tan et al. 2009).
description: Published as part of 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), pp. 91-137 in Cryptogamie, Mycologie 20 (5) on pages 112-114, DOI: 10.5252/cryptogamie-mycologie2022v43a5, http://zenodo.org/record/7829356