Cabalodontia brunnea Westphalen & Regio 2026, sp. nov.

Cabalodontia brunnea Westphalen & Regio sp. nov. Figs 7 C, 7 D, 11 B Etymology. Refers to the brownish basidiomes. Diagnosis. Characterized by the pale brown basidiomes with short, irregular spines, hyaline to yellow hyphae, and basidiospores (3.7 –) 4–4.7 (– 4.9) × 2.4–3.0 (– 3.1) μm. Typification. Brazil. Rio Grande do Sul: Caxias do Sul, Cânion Palanquinhos, 18 Sep. 2017, M. C. Westphalen 600 / 17 (SP 512588). Description. Basidiomes adnate, resupinate, annual, not detaching, forming confluent large patches on the substrate, soft and somewhat brittle; sterile margins absent or very thin, fimbriate to byssoid, up to 1 mm wide. Hymenophore pale brown to ochraceous when fresh, unchanging or slightly darker upon drying, formed by small irregular spines, up to 0.5 mm long, often somewhat cluttered, very brittle upon drying, 6–9 per mm. Subiculum beige to pale yellowish brown, homogeneous, thin and fragile, cottony, up to 0.5 mm thick. Hyphal system monomitic, hyphae more densely arranged towards the trama and looser near the substratum; generative hyphae clamped, thin- to thick-walled, often branching near the septa or at clamp connections, 2.5–5 μm wide, hyaline to pale yellow, golden yellowish-brown in mass, CB +. Skeletocystidia abundant, heavily encrusted, arising from sclerified generative hyphae in the subiculum and projecting toward the trama and above the hymenium, clavate or more commonly tapering towards the apex, encrusted portion 25–70 (– 100) × 5–9 (– 12) μm. Basidia clavate, tetrasterigmate, 13–16 × 4–5 μm. Basidiospores ellipsoid, hyaline, thin-walled, (3.7 –) 4–4.7 (– 4.9) × 2.4–3.0 (– 3.1) μm, IKI –, CB –. Habitat and distribution. Known only from the type locality in Araucaria forests in Rio Grande do Sul State. Growing on dead logs of unidentified angiosperms. Notes. Cabalodontia brunnea is distinguished within the genus by its pale brown basidiomes with irregular short spines and a somewhat farinaceous appearance due to the encrusted cystidia. Microscopically, it presents yellowish hyphae and ellipsoid basidiospores measuring (3.8 –) 4–4.7 (– 4.9) × 2.4–3.0 (– 3.1) μm. As in the case of C. albofulva, this species is known only from its type locality in southern Brazil. Despite extensive sampling in the region, including nearby Araucaria forests, no additional specimens have been found, suggesting that it could represent a rare taxon. Phylogenetically, C. brunnea is closely related to C. delicata, a species also found in Araucaria forests and high-altitude Atlantic rainforest areas (Westphalen et al. 2019). However, C. delicata is relatively common in these habitats and differs from C. brunnea by its pale white to cream-colored basidiomes, shorter aculei, and smaller, subglobose to broadly ellipsoid basidiospores.