Type: Brazil. São Paulo: Serra near to Santos, 1844, Weddel s.n., (H-NYL35210 – holotype, fide Fleig 1997).
Description. Thallus corticolous; uppersurface whitish gray to ivory, shiny to ± dull, epruinose, emaculate, but occasionally in parts irregularly cracked; abundantly isidiate; isidia initially marginal but soon spreading across the thallus surface and, where eroded, frequently leaving distinct circular scars, cylindrical, simple to sparsely branched, brown at their tip or concolorous with the thallus surface, eciliate; lobes broad, small to moderate-sized, 0.7–6(–8) mm wide, ± rotund, axils incised, margin sparsely ciliate; cilia short and slender, 0.2–1(–1.5) mm long, black, mostly simple, very rarely branched; lowersurface with a broad, deep brown, erhizinate, ~ 1–3 mm wide margin, blackening and densely rhizinate towards the thallus center; rhizines long, slender, black, mostly simple, rarely sparsely branched; medulla white. Apothecia and pycnidia not observed among the Galapagos specimens.
Chemistry. Cortex with atranorin [P+ yellow, K+ yellow, KC–, C–, UV–]; medulla with stictic, constictic and cryptostictic acid, and norlobaridone [P+ slowly orange, K+ yellow, KC+ rosé, turning orange, C+ rosé, turning orange, UV–].
Ecology and distribution. Africa, North and South America (Dodge 1959; Hale 1979; Fleig 1997; Eliasaro & Donha 2003; Spielmann & Marcelli 2009; Benatti & Marcelli 2010). New for Ecuador; from the Galapagos previously reported only online in Bungartz et al. (2016) and mentioned by Miquel & Bungartz (2017) as habitat and food for the endemic micro-mollusk Pupisomagalapagorum Pilsbry, 1934. So far only a single specimen has been collected, in the humid zone, on the small native tree Zanthoxylumfagara.
Notes. This isidiate corticolous species has only been found once in the Galapagos; due to the presence of norlobaridone it has a very distinctive KC+/C+ medullary spot test reaction: initially rosé, soon turning orange.