Type: Brazil. São Paulo: Campos do Jordão, 1420 m alt, in Podocarpus forest, 11-Dec-1995, Ribeiro, C.H. 939 (SP – holotype, B – isotype, H – isotype, fide Marcelli & Ribeiro 2002).
Description.Thallus corticolous; uppersurface whitish gray to ivory, shiny to ± dull, epruinose, emaculate, but occasionally in parts irregularly cracked; abundantly isidiate; isidia marginal to submarginal, cylindrical, simple to sparsely branched, occasionally closely clustered (caespitose), brown to blackened at their tip and frequently ciliate (having a ‘tufted’ appearance); lobes broad, small to moderate-sized, 0.7–6(–8) mm wide, ± rotund, axils incised, margins abundantly ciliate; cilia moderately long and slender, 0.5–2.5(–5) mm long, black, mostly simple, very rarely branched; lowersurface blackened throughout or with a narrow, deep brown, erhizinate, ~ 1–1.5 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 salazinic acid [P+ deep yellow, K+ yellow, soon turning blood-red, KC–, C–, UV–].
Ecology and distribution. Previously known only from Brazil (Marcelli & Ribeiro 2002). New for Galapagos and Ecuador; currently known from a single specimen collected on plant debris below a boulder in the transition zone of San Cristóbal Island.
Notes. This species differs from P. crinitum by its chemistry (salazinic instead of stictic acid). Whereas in Galapagos P. crinitum is among the most common isidiate Parmotrema species, P. neosubcrinitum has only been found once.