Pseudopyrenula guianensis

Pseudopyrenula guianensis
Scientific classification
Kingdom: Fungi
Division: Ascomycota
Class: Dothideomycetes
Order: Trypetheliales
Family: Trypetheliaceae
Genus: Pseudopyrenula
Species:
P. guianensis
Binomial name
Pseudopyrenula guianensis
Aptroot (2016)

Pseudopyrenula guianensis is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae.[1] It is known from lowland rainforest in northern South America, with records from French Guiana (type locality near Saül) and Suriname.[2]

Taxonomy

The species belongs to the Pseudopyrenula subgregaria group (the smaller-spored, 3-septate Pseudopyrenula). It is distinguished within that assemblage by two features used by lichenologists for identification: a clear but oil-dotted internal matrix (a hyaline hamathecium with inspersion) and the presence of the fluorescent compound lichexanthone in the thallus. The type collection was made in 1986 near Saül, French Guiana.[2]

Description

The thallus is thin, whitish and ecorticate (lacking a differentiated outer cortex). Sexual fruiting bodies (ascomata) are produced singly; they are black, hemispherical, and 0.3–0.5 mm in diameter, each with a tiny pore at the top (an apical ostiole). Inside, the hamathecium is colourless but contains scattered oil droplets (inspersion). The ascospores are colourless, divided by three cross-walls (3-septate), and measure 21–25 × 6–9 μm; they are smooth-walled and show diamond-shaped internal cavities (lumina) formed by thickening of the inner spore wall.[2]

The thallus is UV-positive yellow under long-wave ultraviolet light, indicating lichexanthone; thin-layer chromatography confirms this compound.[2]

Habitat and distribution

Pseudopyrenula guianensis grows on smooth bark of trees in rainforest. It is confirmed from French Guiana and Suriname.[2]

References

  1. ^ "Pseudopyrenula guianensis Aptroot". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 30 August 2025.
  2. ^ a b c d e Aptroot, André; Ertz, Damien; Etayo Salazar, Javier Angel; Gueidan, Cécile; Mercado Diaz, Joel Alejandro; Schumm, Felix; Weerakoon, Gothamie (2016). "Forty-six new species of Trypetheliaceae from the tropics". The Lichenologist. 48 (6): 609–638. doi:10.1017/s002428291600013x.