Fuscoporia nebularis Comin, Alves-Silva & Drechsler-Santos, 2024

Comin, Marcel, Alves-Silva, Genivaldo, Salvador-Montoya, Carlos A., Góes-Neto, Aristóteles & Drechsler-Santos, Elisandro Ricardo, 2024, Fuscoporia nebularis, (Hymenochaetaceae) a new endemic and threatened species from the cloud forests of southern Brazil, Phytotaxa 664 (1), pp. 12-30 : 18-23

Fuscoporia nebularis Comin, Alves-Silva & Drechsler-Santos sp. nov. Figs. 2 , 3

MycoBank #850660

Diagnosis: —Similar to Fuscoporia wahlbergii and F. torulosa , but F. nebularis differs from F. wahlbergii by having broadly ellipsoid basidiospores, and from F. torulosa by having smaller spores (4–6 × 3–5 vs. 2.9–3.8 × 2.3–3.1 µm).

Etymology: —The epithet ' nebularis ' derives from the Latin 'nebul,' meaning 'a cloud' or 'mist,' and is combined with the Latin adjectival suffix '-aris,' meaning 'found in.' This name indicates it is found in the cloud forests of southern Brazil.

Holotype:— BRAZIL. Santa Catarina, Urubici, Parque Nacional São Joaquim , growing at the base of the trunk of Crinodendron brasiliense Reitz & L.B.Sm. (1958: 20) , 22 August 2019, coll. M. Comin, ( CM254 ) ( FLOR75497 ), GenBank accession numbers: ITS=OR771947; nrLSU=OR827316.

Description:— Basidiomata perennial, pileate to effuse-reflexed, sessile, solitary to imbricate, applanate to triquetrous, measuring up to 19 cm length, 12 cm width, 5 cm thickness; upper surface dark brown (7F8) when fresh and light brown (7D8) when dry, tomentose to somewhat strigose-matted, narrowly zonate, covered with algae and mosses; context brown (5E8) to yellowish brown (5D8), hard and woody, up to 5 mm thick; margin obtuse to sharp. Pore surface refringent, brownish yellow (5C8) when fresh and brown (6D8) when dry; pores round, 6–8 pores/mm, (76–)81.8–157.2(–218.6) µm diam. (av. = 111.3 µm); dissepiments entire, thin to thick, (55–)59.5–143.2(–218.6) µm diam. (av. = 101.5 µm); tubes up to 30 mm long, showing distinct layers, sometimes with thin layers of context between the layers of tubes, woody, slightly paler than the context.

Hyphal system dimitic; generative hyphae 1.5–2.0 µm in diam., thin-walled, hyaline to pale yellowish, simpleseptate; skeletal hyphae thick-walled, yellowish brown in KOH, unbranched, 2.0–3.0 µm in diam. Hymenium, setae 24–30 × 3.9–8 µm, thick-walled, subulate, straight to curved and rarely with bifurcate apex. Cystidioles absent. Basidia 10–15 × 4–8 µm, clavate to subglobose. Basidiospores broadly ellipsoid, thin-walled, hyaline, IKI–, (2.8–)2.9–3.8(– 4.3) × (2.2–)2.3–3.1(–3.3) µm, L = 3.3 µm, W = 2.7 µm, Q = 1.4.

Distribution and habitat:—This species is found in the cloud forests of southern Brazil. The basidiomata grow at the base of live and dead trunks of Crinodendron brasiliense , Drimys angustifolia Miers (1858: 46) , Myrceugenia glaucescens (Cambess.) D. Legrand & Kausel (1943: 7) , M. myrsinoides (O. Berg ex Mart. in Mart.) D. Legrand (1953:9), M. ovalifolia (O. Berg) Landrum (1984: 163) , and M. regnelliana (O. Berg ex Mart.) D. Legrand & Kausel (1953: 11) .

Conservation status:—Endangered. Fuscoporia nebularis is considered endemic to the cloud forests of southern Brazil. The ecosystem where it is found is restricted to areas above 1,000 m. a.s.l. that are naturally fragmented and dependent on specific microclimatic conditions ( Bruijnzeel et al. 2010, Oliveira et al. 2014). This makes it susceptible to threats caused by climate change ( Salazar et al. 2007, Williams et al. 2007, Goldsmith et al. 2013, Gotsch et al. 2014, Pompeu et al. 2014, Helmer 2019) and human activities such as cattle grazing, introduction of invasive species, anthropogenic fire, and land use changes ( Brooks & Balmford 1996, Pinto et al. 2006, Tabarelli et al. 2010), resulting in a continuing decline of habitat.

In over 10 years of sampling, the species has been collected in total about 50 times from the following three sites: São Joaquim National Park, Aparados da Serra/Serra Geral National Park, and Bom Jardim da Serra Wind Farm. It is expected to occur in up to 100 sites across its potential suitable habitat, with up to 50 mature individuals per site, resulting in a population size of no more than 5,000 mature individuals, belonging to a single subpopulation.

Considering that it is not restricted to one plant host and is not extremely rare despite likely being endemic to the cloud forests of southern Brazil, it is expected that the population decline could be between 60–80 % in the next 50 years (a three-generation length of fungal species), mainly due to habitat degradation and the impacts of climate change ( Helmer et al. 2019). Based on its population size and the decline in area and quality, this species is assessed as Endangered (EN A3c).

Additional materials (paratypes): — BRAZIL. Santa Catarina: Urubici, Parque Nacional de São Joaquim , 11 October 2016, coll. M. Comin, CM077 ( FLOR75478 ) ; ibid., 29 August 2018, coll. L. A. Funez, LF 06 ( FLOR75500 ) ; ibid., LF07 ( FLOR75501 ) ; ibid., LF43 ( FLOR75502 ) ; ibid., LF44 ( FLOR75503 ) ; ibid., at the base of living Myrceugenia myrcioides , 30 September 2018, coll. M. Comin, CM99 ( FLOR75479 ) ; ibid., 30 September 2018, coll. M. Comin, CM101 ( FLOR75480 ) ; ibid., 4 October 2018, coll. M. Comin, CM110 ( FLOR75481 ) ; ibid., at the base of living M. myrcioides , 4 October 2018, coll. M. Comin, CM112 ( FLOR75482 ) ; ibid., at the base of dead standing Drimys angustifolia , 4 October 2018, coll. M. Comin, CM114 ( FLOR75483 ) ; ibid., at the base of living M. glaucescens , 5 October 2018, coll. M. Comin, CM120 , ( FLOR75484 ) ; ibid., at the base of Myrceugenia sp. , 5 October 2018, coll. M. Comin, CM121 , ( FLOR75485 ) ; ibid., on dead standing M. glaucescens , 5 October 2018, coll. M. Comin, CM123 ( FLOR75486 ) ; ibid., on living Myrceugenia sp. , 5 October 2018, leg. M. Comin, CM124 ( FLOR75487 ) ; ibid., 6 November 2018, coll. M. Comin, CM128 ( FLOR75488 ) ; ibid., 7 November 2018, coll. M. Comin, CM129 ( FLOR75489 ) ; ibid., coll. M. Comin, CM130 ( FLOR75490 ) ; ibid., Morro da Igreja , at the base of living M. regnelliana , 21 August 2019, coll. M. Comin, CM248 ( FLOR75491 ) ; ibid., coll. M. Comin, CM249 ( FLOR75492 ) ; ibid., coll. M. Comin, CM250 ( FLOR75493 ) ; ibid., on dead standing Myrtaceae , 22 August 2018, coll. M. Comin, CM251 ( FLOR75494 ) ; ibid., at the base of living M. regnelliana , 22 August 2018, coll. M. Comin, CM252 ( FLOR75495 ) ; ibid., CM253 ( FLOR75496 ) ; ibid., at the base of Crinodendron brasiliense , 22 August 2019, coll. M. Comin, CM254 ( FLOR75497 ) ; ibid., on dead standing Myrceugenia sp. in an advanced stage of decomposition, 24 August 2019, coll. M. Comin, CM257 ( FLOR75498 ) ; ibid., at the base of living M. ovalifolia , 28 August 2018, coll. M. Comin, CM263 ( FLOR75499 ) ; ibid. Rio Grande do Sul, Cambará do Sul, Aparados da Serra , in broken standing trunk, 27 May 2021, coll. T. Kossmann, MIND. Funga 0865 ( FLOR75504 ) ; ibid., Bom Jardim da Serra, Parque Eólico Bom Jardim , on dead trunk of standing Myrceugenia sp. , 31 October 2021, coll. T. Kossmann, MIND. Funga 1340 ( FLOR75505 ) .

......continued on the next page a = Chen et al. 2020

b = Groposo et al. 2007

c = observed during this study

d = Dai 2010

e = Hussain et al. 2022

f = Yuan et al. 2020

Figures

FIGURE 2. Fuscoporia nebularis sp. nov. Holotype (FLOR75497). A. Basidioma in situ B. Hymenial setae in Melzer’s Reagent. C. Hymenial setae in KOH + Phloxine. D. Hymenial setae in Melzer’s Reagent. E. Basidiospores in KOH. Scale bars: A = 2 cm; B, C, D, E = 20 µm. Photographs by: M. Comin.

FIGURE 3. Distribution map of Fuscoporia nebularis. The polygons are the delimitations of biogeographic provinces of the Neotropical region provided by Morrone et al. (2022). Figure by: M. Comin.