Parmotrema pachydermum (Hue) Blanco, Crespo, Divakar, Elix & Lumbsch, Mycologia 97(1): 157. 2005.
Hue (1899) described Parmelia pachyderma from Montevideo, Uruguay. Hale (1976) combined it in the genus Everniastrum, and Culberson & Culberson (1981) in the new, endemic genus Concamerella. In 2005, based on genetic evidence (although not from this species, but from Concamerella fistulata (Tayl.) W Culb. & C. Culb.), this species was finally placed in the genus Parmotrema (Blanco et al. 2005).

This species is endemic to Rio Grande do Sul State (Southern Brazil) and Uruguay, and is suffering habitat loss by extensive soy plantations associated with fires.

EOO=104671 km2, AOO=28 km2
AOO reduction = 37%
EOO reduction = 14%

Locations = 8-15
Mature individuals = 1 site = 50-100 individuals, all other sites 1-5 individuals
total = 57-170

Generation length = 30 years

Habitat decline = 44% deforestation

EN C2a(i) D
C1(?)

Parmotrema pachydermum is endemic of Southern Brazil (Rio Grande do Sul) and Uruguay. No collections are known from the adjacent Santa Catarina (Brazil) or even Paraguay or Argentina. Apparently the species is typical for the Pampa Biome, although some rare individuals were found in the Rio Grande do Sul Highlands (“Campos de Cima da Serra”), that actually are quite similar to Pampa.
The type collection of P. pachydermum is from Montevideo, Uruguay. Additional localities from Uruguay include Durazno, Lavalleja, Maldonado and Rocha (Culberson & Culberson 1981).  From Brazil it is known from Rio Grande do Sul only, reported for Bagé, Caçapava do Sul, Guaíba, Porto Alegre and São Francisco de Paula (see the references in Spielmann 2006, as Concamerella pachyderma), and Piratini (field observations).

Parmotrema pachydermum is typical of the Pampa biome. It is exclusively saxicolous and grows at sunny places, usually at rocky outcrops or mountains.

The Pampa Biome is suffering a lot of threat in recent years, especially by the extensive soil use for soy plantation and parallel fires, which can reach the rocks where Parmotrema pachydermum grows.

One of the most representative populations of Parmotrema pachydermum stands in Cerro do Ubaldo, Municipality of Piratini, Rio Grande do Sul. Piratini was one of the places where Malme collected many lichens during the First Regnellian Expedition (1892-1894). This place should be elected as a specially protected area.

The real range of distribution of Parmotrema pachydermum requires more field work. No genetic data are known either, although recent collections are under study.

None.