Rhizoplaca occulta S. Leavitt, F. Fernandez-Mendoza , Lumbsch, Sohrabi & L. St. Clair

Leavitt, Steven D., Fernandez-Mendoza, Fernando, Perez-Ortega, Sergio, Sohrabi, Mohammad, Divakar, Pradeep K., Lumbsch, H. Thorsten & Clair, Larry L. St., 2013, DNA barcode identification of lichen-forming fungal species in the Rhizoplaca melanophthalma species-complex (Lecanorales, Lecanoraceae), including five new species, MycoKeys 7, pp. 1-22 : 8-9

Rhizoplaca occulta S. Leavitt, F. Fernandez-Mendoza, Lumbsch, Sohrabi & L. St. Clair sp. nov.

Type.

USA, Nevada, White Pine County, on Cave Mountain, north of antenna site, Humboldt-Toiyabe National Forest, 39.1734°N, 114.6130°W, on basalt, 3150 m alt., July 2010, S. D. Leavitt & Larry L. St. Clair BRY-C55076 (holotype BRY).

Description.

Consists of specimens recovered within 'clade IVa’ in Leavitt et al. (2011a), which is supported as a lineage distinct from all other populations according to coalescent-based genetic analysis of multiple genetic loci. This species is morphologically variable. While some individuals are morphologically similar to Rhizoplaca melanophthalma sensu stricto, vagrant forms, including Rhizoplaca cerebriformis ined. and Rhizoplaca subidahoensis ined. which have been suggested to be distinct species based on morphology ( Arup and Grube 2000; figs 7 & 9), also belong within this species. The mean genetic distance among ITS haplotypes was estimated to be 0.003 ± 0.001.

Chemistry - Usnic (major), constipatic (minor), dehydroconstipatic (minor), 2'-O-demethylpsoromic (minor), and 2'-O-demethylsubpsoromic (minor or trace) acids; usually with psoromic acid (major); and occasionally with dehydroprotocetraric acid (minor).

Reference phylogeny.

Leavitt et al. 2011a (fig. 5, 'clade IVa’).

Reference sequences.

GenBank Nos. HM577307 (ITS), HM577081 (IGS), HM577210 (group I intron), HM577441 (MCM 7), and HM576952 (β-tubulin).

Phylogenetic notes: Strongly supported as monophyletic lineage in both concatenated multilocus gene tree (ML bootstrap = 100%: posterior probability = 1.0) and the ITS gene topology (ML bootstrap = 99%, this study); and strong speciation probability inferred from multiple loci (BPP speciation probability ≥ 0.98). Rhizoplaca occulta belongs to a closely related, and well-supported, monophyletic lineage including Rhizoplaca paralis , Rhizoplaca polymorpha , Rhizoplaca porterii , and the obligatory vagrant species Rhizoplaca haydenii and Rhizoplaca idahoensis .

Ecology and distribution.

Growing usually on exposed calcium-poor rock (e.g. basalt, granite, schist) in pinyon-juniper woodlands but also occurs free on soil. So far known only from collections in western North America. Rhizoplaca occulta included a total of five individuals from Idaho (3 individuals), Nevada (1), and Utah (1), USA, and included GenBank accessions identified as Rhizoplaca cerebriformis ined. (AF159942) and Rhizoplaca subidahoensis ined. (AF159944).

Etymology.

The name is derived from the Latin “occultus,” meaning hidden, and refers to the fact that this species was hidden within the phenotypically circumscribed taxon Rhizoplaca melanophthalma sensu lato.

Specimens examined.

See supplementary file 1.