Enterographa dokdoensis

Enterographa dokdoensis is a species of saxicolous (rock-dwelling), script lichen in the family Roccellaceae. It occurs in South Korea. The lichen has a thallus that can cover areas up to 5–10 cm in diameter, with a smooth to roughened texture and a green-grey to mauve colour.

Taxonomy

Enterographa dokdoensis was formally described as a new species in 2020 by lichenologists Sergey Kondratyuk, Lőkös, Beeyoung-Gun Lee, and Jae-Seoun Hur. The type specimen of Enterographa dokdoensis was collected by the third author from the Liancourt Rocks in the Republic of Korea, specifically on the Eastern (Dokdo) Islet. This collection was made at the seashore, on the left side of the dock, where the lichen was found growing on rocks alongside Opegrapha ulleungdoensis. The elevation of the site is about 5 meters above sea level. The naming of dokdoensis alludes to its type locality – Dokdo (Eastern) Island of the Dokdo Islands in South Korea.

Description

The thallus of Enterographa dokdoensis can cover areas up to in diameter or even larger. The thallus has a smooth to texture, a green-grey to mauve colour, and can reach a thickness of up to 200 ÃŽÂ¼m. Occasionally, the thallus may display soredious spots. The of this species is Trentepohlia, with algal cells measuring 6.4–9.6 ÃŽÂ¼m in diameter. The of Enterographa dokdoensis is typically indistinct or absent.

The ascomata (fruiting bodies) of this lichen are open and shortly , sometimes branching, and measure 0.1–0.2 by 0.2–1.2 mm. They are rarely ellipsoid and not embedded in a . The of the ascomata is mostly pale brown, occasionally darkening to a dark brownish hue, and is not . The can be up to 32–50 ÃŽÂ¼m wide. The is very thin, ranging from 12 to 20 ÃŽÂ¼m in width, and appears pale or yellowish. The is hyaline and measures 25–50 ÃŽÂ¼m in height. The hymenium is also hyaline and reaches a height of 50–60 ÃŽÂ¼m. within the hymenium are 0.8–1.0 mm wide, with their apices branching and anastomosing, particularly in the upper part, and expanding to about 15 ÃŽÂ¼m wide. The is 2–5 ÃŽÂ¼m thick and contains yellowish crystals that are 2–5 ÃŽÂ¼m in diameter.

The asci of Enterographa dokdoensis are cylindrical and contain eight spores. These ascospores are (threadlike) and not curved, typically with 3–5 septa, measuring 20.8–30.4 by 1.6–3.5 ÃŽÂ¼m, and are surrounded by a thin . The are (point-like), up to 0.1 mm in diameter, and immersed in the thallus. They appear yellowish or brownish, with a pale yellowish wall in section. The are (threadlike) and curved, measuring 12–20 by 0.8 ÃŽÂ¼m.

Chemically, the thallus of Enterographa dokdoensis reacts C+ (red), is K− and PD−, and UV+ (pale cream) to standard spot tests. Gyrophoric acid is present in this species.

Similar species

Enterographa dokdoensis shares several characteristics with other species of the genus Enterographa, yet it can be distinguished by specific features. It is similar to the pantropical species E. leucolyta, which typically grows on shaded, coastal volcanic rocks. However, Enterographa dokdoensis differs in having a lower hymenium (50–60 ÃŽÂ¼m vs. 120 ÃŽÂ¼m), somewhat narrower and longer ascospores (20–30.5 by 1.6–3.5 ÃŽÂ¼m vs. 18–27 by 2.5–4 ÃŽÂ¼m), and shorter conidia (12–20 ÃŽÂ¼m vs. 20–25 ÃŽÂ¼m long).

There was a previous record of E. leucolyta from South Korea's Geumodo Island that might pertain to Enterographa dokdoensis. This is due to the much higher hymenium (120–130 ÃŽÂ¼m) in the recorded specimens, which is unlike the typical hymenium height of E. leucolyta (55–100 ÃŽÂ¼m). Additionally, Enterographa dokdoensis resembles the Australian epiphytic species E. divergens in its very thin, smooth or slightly wrinkled thallus. However, it differs in having a light whitish-grey thallus (as opposed to brownish-grey), indistinct apothecia, a light brown disc (instead of black), and shorter, narrower ascospores that are 3–5-septate (measuring 20.8–30.4 by 1.6–3.5 ÃŽÂ¼m vs. 24–32 by 3–4 ÃŽÂ¼m, 7-septate).

Enterographa dokdoensis is similar to E. praepallens from Japan, especially in the appearance of its apothecia and disc colour. It differs in having a thinner whitish-grey thallus and a lower hymenium. Its ascospores are almost the same as those of E. praepallens. Enterographa dokdoensis can also be compared to E. anguinella from Japan and the Philippines. It is distinguished by its matt whitish-grey thallus (as opposed to grey to light ochre and slightly shiny), indistinct apothecia, and shorter, narrower ascospores that are 3–5-septate (20.8–30.4 by 1.6–3.5 ÃŽÂ¼m vs. 22–38 by 3–4 ÃŽÂ¼m, 7–9-septate).

References