Inonotus parvisetus V.R.T. Oliveira, Xavier de Lima & Gibertoni, 2022

X, Vitor, Lima, avier de, T, Virton Rodrigo, Oliveira, argino de, C, Nelson, Lima-Júnior, orreia de, C., José Ribamar, Oliveira-Filho, Santos, Carla, Lima, Nelson & Gibertoni, Tatiana Baptista, 2022, Taxonomy and phylogenetic analysis reveal one new genus and three new species in Inonotus s. l. (Hymenochaetaceae) from Brazil, Cryptogamie, Mycologie 20 (1), pp. 1-21 : 7-10

Inonotus parvisetus V.R.T. Oliveira, Xavier de Lima & Gibertoni , sp. nov.

This species is characterized by the pileate basidioma, narrow tramal setae, absence of hymenial setae, pores 6-8/mm and basidiospores 4.5-5 Μm long.

MYCOBANK NUMBER. — MB 837431.

HOLOTYPE. — Brazil. Alagoas State, Quebrangulo City , REBIO de Pedra Talhada, on dead wood, 09°15’27.0”S, 36°24’44.0”W, 515 m, 19.VII.2018, V. R. T. Oliveira, ( URM [ URM94334 ]).

ADDITIONAL SPECIMEN EXAMINED. — Brazil. Alagoas State, Quebrangulo City, REBIO de Pedra Talhada, on dead wood, 09°15’27.0”S, 36°24’44.0”W, 515m, 14. V.2019, V. R. T. Oliveira, ( URM [94335]).

ETYMOLOGY. — From parvus (Latin) meaning “small”. Referring to the smaller tramal setae in comparison to similar species of the genus.

HABITAT AND DISTRIBUTION. — Tropical, ombrophilous broadleaf forest.

DESCRIPTION

Basidioma perennial, pileate ( Fig. 4 A-B), sessile, broadly attached to dimidiate, solitary to imbricate, convex to triquetrous in section, 2.3-6.7 cm wide, 2.1-4 cm long, 1.1- 2.7 cm thick at the base, hard, light. Pileus surface firstly tomentose, yellowish-brown, but forming a hard, darker to black crust of agglutinated hyphae with age, concentrically sulcated, cracking radially in older parts. Margin obtuse. Pore surface ( Fig. 4C ) dark brown, pores round, 6-8/mm; margin sterile, yellow to brownish-yellow. Context golden-brown, duplex, with a thin black line near the pilear surface. Tubes concolorous with the context, tube layers (up to four layers in the holotype) separated by a thin layer of context, old tubes filled with concolorous to whitish mycelia. Context and tubes turning black in KOH 3%, drying out as dark spot. Hyphal system in the context monomitic, generative hyphae simple and mostly regularly septate, sparingly branched, hyaline, yellow, golden yellow in water and rusty brown in KOH, mostly thick-walled with wide to narrow lumen, rarely hyaline and thin-walled, 3-5.5 Μm in diameter; black line ( Fig. 4D ) composed by dark reddish-brown, more densely agglutinated and intertwined hyphae; below the line, hyphae grow parallel to the pilear surface, near the tube they grow downwards to form the tube trama, and above the line, hyphae concolorous or slightly darker, growing upwards to compose the tomentum. Tomentum dense, hyphae straight, thick-walled with a wide lumen, yellow to dark yellow in water, rusty brown in KOH 3%, 3.4-5.5 Μm diameter, ends obtuse, mostly broken and agglutinated in older parts of the pileus. Tube trama monomitic, hyphae grown straight perpendicular to the pilear surface, generative hyphae hyaline to yellow, thin to slightly thick-walled, 2.5-4 Μm in diameter. Tramal setae ( Fig. 4E ) abundant to rare in the holotype, brownish yellow in water, dark rusty-brown in KOH 3%, more frequent near pore mouths, often protruding out of dissepiment, 45-80 × 6-8.5 Μm. Basidia not observed. Basidiospores ( Fig. 4F ) subglobose, 4-5.5 × 4-5 Μm (Q = 1-1.1), thick-walled, smooth, pale yellow in water and golden yellow to rusty brown in 3% KOH, CB-, IKI-.

REMARKS

Macroscopically, this species is very similar to other pileate species of Inonotus s.l. found in the region. However, the presence of monomitic tube trama, tramal setae and subglobose basidiospores readily places this species in Inonotus s.s. Regarding species recorded in Brazil, it is similar to I. amazonicus Gibertoni & Ryvarden , I. brasiliensis Xavier de Lima & Ryvarden and I. patouillardii (Rick) Imazeki by the presence of tramal setae and absence of hymenial setae. Inonotus amazonicus has wider tramal setae (10-35 Μm); I. brasiliensis is annual, pileus surface yellowish and has larger tramal setae (up to 120 × 15); I. patouillardii has wider pores (3-4/mm) and is usually recorded as parasitic ( Gottlieb et al. 2002).

Figures

FIG. 4. — Inonotus parvisetus V.R.T. Oliveira, Xavier de Lima, Gibertoni, sp. nov. (URM94334): A, B, dried basidiomata of the holotype; C, pore surface; D, longitudinal section of the dried basidioma, red arrow pointing the black line in the context; E, tramal setae; F, basidiospores; G, generative hyphae of the context. All preparations in 3% KOH. Scale bars: A, B, 1 cm; C, 1 mm; D, 5 mm; E-G, 10 μm.