Trapelia herteliana Fryday
Biblioth. Lichenol. 88: 143. 2004.

Thallus widespreading, 5-10 cm across, but often confined to depressions in the substratum, thin, 0.1 mm thick, cream with a pinkish tinge, areolate; areoles 0.2-0.4 mm across. Photobiont chlorococcoid, cells globose, 8.5-12 m diam.
Apothecia immersed, with a pseudothalline margin, typically narrowly elongate, 0.3-0.4 x 0.1-0.15 mm, but occasionally more rounded; disc red- to dark brown but usually, at least partly white pruinose, separated from the thallus by a thin fissure Exciple thin, pale orange. Hypothcium pale orange-brown, 50-60 m thick, mostly composed of vertically orientated hyphae. Hymenium hyaline, 80-90 m thick, I+ blue; epihymenial zone 15-20 m, orange-brown, granular. Paraphyses slender, 1.5-2.0 m, septate, richly branched and anastomosing, slightly swollen at the apices to 3.5 m, without a pigmented cap. Asci broadly cylindrical, 60-70 x 18-20 m Trapelia-type. Ascospores simple, hyaline, (15-)17-20(-22) x 9-9.5(-11) m.
Conidiomata pycnidia, round, 0.025-0.03 mm diam., dark brown, level with the thallus surface or slightly raised. Conidia filiform, curved, 15-20 x 0.8 m.

Chemistry: K, C+ red, Pd. Gyrophoric acid detected by TLC.

Distribution & Ecology: Known only from a single locality from siliceous rocks on Campbell Island.

Notes: The new species is easily recognized by its elongate, immersed apothecia. In many ways (e.g. elongate apothecia, chemistry) it resembles some species of Rimularia (e.g. Rimularia badioatra), but it is placed in Trapelia on account of its curved, filiform conidia and pale thallus; conidia in Rimularia are generally straight and much shorter (Coppins & Kantvilas 2001). It is possible that the R. badioatra group may be close to Trapelia, but unfortunately, pycnidia have not been observed in any members of the group. Other genera in the Agyriaceae with filiform conidia are Placopsis, which has lecanorine apothecia, and Oreceolina, which is confined to Iles Kerguelen and has a thallus lacking lichen substances (Lumbsh 1997).
The single associated species was Rhizocarpon geographicum.

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Thallus and apothecia