Dirina arabica

Dirina arabica is a species of saxicolous (rock-dwelling), crustose lichen in the family Roccellaceae. Found in Socotra, it was formally described as a new species in 2013 by lichenologists Anders Tehler and Damien Ernst. The type specimen was collected by the first author near the village in Homill, at an altitude of 350 m. The species epithet refers to Arabia, the geographical location encompassing the type locality. The lichen is endemic to Socotra, where it grows on Eocene limestone rocks. It has a creamy-white, slightly thallus that is 0.1–0.5 mm thick and a chalk-like medulla. There are no soralia on the thallus. The ascomata have a circular outline and measure up to 2.0 mm in diameter, and have a pruinose, white-grey with a. Dirina arabica is a sister species to Dirina immersa, a sympatric species that can be distinguished from the former by its ascomata.