Porina muralisidiata
Porina muralisidiata is a corticolous lichen in the family Porinaceae. It forms olive-brown patches on tree bark in lowland southern Brazil. The species is densely covered with gnarled, finger-like isidia. It also has unusually large, many-chambered ascospores, a combination not reported in any other known Porina species. It was formally described in 2022 from material collected on roadside trees along a lakeshore at Ipanema in Porto Alegre and is known only from this locality.
Taxonomy
Porina muralisidiata was described in 2022 by André Aptroot from material collected on the bark of roadside trees along a lake at Ipanema, Porto Alegre, Rio Grande do Sul, Brazil, at sea level. The holotype is deposited in the herbarium of the . The species was characterized as a corticolous Porina with a thallus bearing gnarled isidia and large, ascospores measuring 110–132 × 15–18 μm. No other known Porina species was reported to combine muriform ascospores with an isidiate thallus, supporting recognition of P. muralisidiata as a distinct species. The specific epithet muralisidiata refers to the muriform ascospores and the isidia.
Description
The thallus of Porina muralisidiata is continuous with an irregular, slightly glossy surface. It is olivaceous brown, up to about across and up to 0.1 mm thick, and it is not bordered by a distinct . The thallus is densely covered with numerous isidia, which are gnarled and about 0.1 mm wide; they may be simple or branched and often occur in clusters. The is . The perithecia are superficial and not covered by the thallus. They are black, globose to hemispherical with a constricted base, 0.4–0.6 mm in diameter and about 0.4 mm high; the perithecial wall is reddish inside. The ostioles are apical, single, black, and protruding, about 0.1 mm in diameter. The is not . Ascospores are produced eight per ascus. They are hyaline,, and muriform, measuring 110–132 × 15–18 μm, and they lack a surrounding gelatinous sheath. Pycnidia have not been observed. In standard spot tests the thallus is UV–, C–, K–, KC– and P–. Thin-layer chromatography did not detect any distinctive secondary metabolites.
Habitat and distribution
Porina muralisidiata grows on the bark of roadside trees along a lakeshore at Ipanema in Porto Alegre, Rio Grande do Sul, Brazil, at sea level. When it was described in 2022, it had not been reported from outside Brazil. The original description also cited an additional specimen from the same locality. No further occurrences had been reported by 2025.