Pycnoporus amazonicus Gurgel & T.S.Cabral, 2025

F., Rafaela Araújo, S., Gurgel Catarina, Leimi, Carvalho Dirce, De, Komura Ruthe, Dalman, Jesus Santos, De, Isadora Fernandes, Vargas-Isla, França Ruby, Ishikawa, Noemia Kazue & Cabral, Tiara Sousa, 2025, A new species and a new record for Pycnoporus P. Karst. (Polyporaceae) from the Brazilian Amazon, revealed by an integrative approach of classical taxonomy and phylogenetic studies, Cryptogamie, Mycologie 20 (5), pp. 61-86 : 70-73

Pycnoporus amazonicus Gurgel & T.S.Cabral , sp. nov.

( Figs 6; 9A, D, G; 10 A-D)

TYPE MATERIAL. — Brazil • Amazonas, Manicoré, Comunidade Barro Alto ; 05.VII.2021; D.L. Komura leg.; DLK3268100; holotype: INPA-Fungos 295581; GenBank : OP198494 - ITS, OP198567 - LSU, PP988043 - tef 1 • Pará, Altamira, Trans Assurini , Travessão da firma; 3°16’47”S, 52°34’54”W; 17.VII.2021; R. J.S. Dalman leg.; RJS51119; paratype: INPA-Fungos 295548 • same data; 09.VII.2022; R. J.S. Dalman leg.; RJS225128; paratype: INPAFungos 295551 • same data; 14.VIII.2022; R. J.S. Dalman leg.; RJS252130; paratype: INPA-Fungos 295552 • same data; R. J.S. Dalman leg.; RJS253131; paratype: INPA-Fungos 295553 • same data; R. J.S. Dalman leg.; RJS254132; paratype: INPA-Fungos 295554 • same data; R. J.S. Dalman leg.; RJS255133; paratype: INPA-Fungos 295555 • same data; R. J.S. Dalman leg.; RJS256134; paratype: INPA-Fungos 295556 • Novo, Vicinal da 16; 10.VII.2021; R. J.S. Dalman leg.; RJS27118; paratype: INPA-Fungos 295547 • same data; 27.VII.2022; R. J.S. Dalman leg.; RJS224125; paratype: INPA-Fungos 295550 • Tocantins, Mateiros, Parque Estadual do Jalapão ; 24. VI.2018; T. B. Gilbertoni leg.; TBG15 ; paratype: URM 93365 .

TABLE 2. — Estimated divergence times obtained in molecular analyses.

DIAGNOSIS. — Differs from the other species in the genus by the basidiome with a soft aspect, orange to matt orange, with brown context mixed with orange and cream zones barely visible, gray line between context and hymenophore, 3-5 pores per mm, with smooth, elongated basidiospores, 5.7-7.9 × 3.0-4.8 µm. It is distinguished from P. coccineus by its context with predominating pale orange zones with moderate orange-yellow, and smaller spore sizes 4.0-5.2 ×2.0-2.3, and from P. sanguineus by its 5-8 pores per mm in the hymenophore.

ETYMOLOGY. — In reference to Amazonia, where the holotype was collected.

DISTRIBUTION. — So far known for Brazil in the Brazilian Amazon (Amazonas and Pará) and the Cerrado biome ( Tocantins).

SUBSTRATE. — Growing on burnt dead trunk of an indeterminate angiosperm and causing white rot.

MYCOBANK. — MB850045.

DESCRIPTION

Basidiome perennial, gregarious, cespitose; varying in shape from dimidiate, dimidiate elongated, semicircular, with attack on the substrate ranging from strongly adhered to semistipitate, 67-115 mm diameter × 47-66 mm width × 4-5 mm thickness, soft and malleable when young, coriaceous with age. Pileus surfacecrusty to smooth, velvety to tomentose, bluish, slightly glossy to opaque, orange (N 00 Y 90 M 60) to matt orange (N 00 Y 99 M 60), and the whole surface becomes yellowish white (N 00 Y 20 M 00) at high temperatures and in older specimens. Margin thick, acute to obtuse, entire to irregular, concolor to pileus surface, or pale orange (N 00 Y 80 M 50). Context and pileus surface form distinct layers in cross-section, fibrousand softcompact, 2-3 mm thick, non-homogeneous zones, predominantly brown (N 60 Y 99 M 70), sometimes merged with orange (N 00 Y 90 M 60) and cream (N 00 Y 40 M 10) zones, with homogeneous orange (N 00 Y 90 M 60) and cream (N 00 Y 40 M 10) zones in

A the apical portion, reflecting the developmental stage. Line grayish brown (N 60 C 00 M 10) and cream (N 00 Y 40 M 10), between the context and the hymenophore. Surface of the pores of the hymenophore bright orange (N 00 C 90 M 60) to moderate reddish orange (N 00 C 90 M 80); pores circular, angular to irregular, 3-5 pores per mm, 0.2 × 0.3 mm diameter; dissepiment thin, entire or lacerated, concolor to the pore surface; tube circular with 1 layer up to 2-2.5 mm deep, about 0.4 mm wide, light orange (N 00 C 80 M 50). Macrochemical reaction occurs when adding 5% KOH resulting in a rapid color change from black to greenish brown in part of the basidiome. Hyphal system trimitic. Pileus surface composed of generative hyphae, 2-4 µm diameter, thin-walled to slightly thick, fused to abundant skeletal hyphae, 3-4µm diameter, hyaline in 5% KOH, CB-; IKI-.Context composed of generative hyphae thin-walled, with frequent clamps, rarely branched, 2-4 µm diameter, hyaline to yellowish in 5% KOH, CB-; IKI-; skeletal hyphae dominate, thick-walled, non-septate, unbranched, straight or slightly tortuous, 3-7µm diameter, hyaline to yellowish in 5% KOH, CB-; IKI-; binding hyphae thick-walled, non-septate, branched with short branches, 2-4 µm diameter, hyaline to yellowish in 5% KOH, CB-; IKI-.Trama of the tubes composed of hyphae similar to the context; skeletal hyphae, 2-5 µm diameter; connective binding hyphae more conspicuous than context, 1-3 µm diameter. Hyphae with orange crystals predominate in all the parts of the basidiome, 2-4 µm diameter, hyaline in 5% KOH, CB-; IKI-. Basidium clavate, 10-16×5-7 µm, with basal clamp, four sterigmata, hyaline in 5% KOH, CB-; IKI-. Basidiospores 5.72-7.96 ×3.06-4.83 µm (x=6.92 ± 0.6×4.01 ± 0.5; Qm =1.7), elongated, smooth, slightly curved, hyaline in 5% KOH, CB-; IKI-.

REMARKS

There is little clarity on the taxonomic value of some morphological characters, such as the presence of a line between context and hymenophore observed in Pycnoporus amazonicus Gurgel & T.S.Cabral , sp. nov. This characteristic is observed below the pileipellis, sometimes in Trametes betulina (L.) Pilát, T. hirsuta (Wulfen) Lloyd , and T. versicolor (L.) Lloyd, and always in the clade meyenii ( Welti et al. 2012). On the other hand, the absence of a black line below the pileus, allied to a glabrous upper surface, and the absence of parietal crystals were diagnostic characteristics used to recognize Leiotrametes Welti & Courtec. (synonym of Cubamyces Murrill ) ( Justo & Hibbett 2011; Welti et al. 2012).

For the species within Pycnoporus , this characteristic was shown to be delimitative, and we report the presence of this characteristic for the first time in specimens of the genus.

When compared to other species in the genus, P. sanguineus has a smooth, zoned pileus, 5-8 pores per mm, context with alternating white and medium orange, scaly to cottony zones, and P. coccineus has a smooth pileus, pores 3-5 per mm, and a context of a pale color, with predominant zones alternating from white to moderate orange ( Nobles & Frew 1962, lectotype analysis), while P. amazonicus Gurgel & T.S.Cabral , sp. nov. has a smooth to tomentose pileus, 3-5 pores per mm, and a context sometimes not visible, predominantly brown, with a grayish line between the context and the hymenophore. With respect to the other two species of the genus, P. cinnabarinus has a thicker basidiome ( 170 mm), 1-4 circular pores per mm ( Nobles & Frew 1962, lectotype analysis), and P. puniceus has a well-supported morphology and phylogeny, with a cinnabar pileus, 1-3 irregular pores per mm and a context with intense and lighter cinnabar zones ( Nobles & Frew 1962; Ryvarden & Johansen 1980; lectotype analysis).

Thus, the morphological characteristics of colours and appearance of the context allied to the presence of a line between the context and the hymenophore and the numbers of pores per mm present in the hymenophore, together with the phylogenetic position within Pycnoporus , forming strongly supported clades in two of the phylogenies ( Figs 3; 4), provide evidence that Pycnoporus amazonicus Gurgel & T.S.Cabral , sp. nov. is a distinct species.