[1] Found in Brazil, it was formally described as a new species in 2013 by lichenologists André Aptroot and Marcela Cáceres.

The lichen is distinguished from other members of genus Porina by its long and thin ascospores, for which the species is named.

[2] The corticate thallus of Porina linearispora is smooth, shiny, and thin, with a green color and no visible warts.

The lichen has perithecioid ascomata that are simple, dispersed, hemispherical, and emergent, with a diameter ranging from 0.2 to 0.3 mm.

The ascospores are hyaline, filiform with rounded ends, and measure 75–90 by 1.5–2.0 μm; they typically have 9 septa (internal partitions), although that number ranges between 7 and 13.