Morphological and nuclear ribosomal DNA data support distinguishing two new species of Umbilicaria (Umbilicariaceae, Ascomycota) from Europe

Umbilicaria iberica and U. maculata are described as new to science on the basis of morphological and molecular data. Umbilicaria iberica is similar to U. polyphylla but differs in having a monophyllous thallus with a distinctive white reticular pattern over the umbilicus and actinodisc apothecia. Umbilicaria maculata is similar to U. cylindrica but this new species is distinguished by its grey-brown thallus with sparse marginal cilia and white stains on the upper surface especially in the marginal zone, as well as by sessile apothecia with one or a few sterile fissures. Nuclear ITS and LSU rDNA have been used as molecular markers. In the phylogenetic analysis U. polyphylla falls into two well supported clades (A and B), one of which corresponds to the morphotype that is described here as a new taxon. Specimens previously recognized as U. cylindrica fall into three well supported clades: clade C corresponds to the typical morphotype, clade D corresponds to morphotype II described here as a new taxon, and clade E is morphotype III which is recognized as U. cf. umbilicarioides. Typical group I introns have been found in position 1506 of the nuclear SSU rDNA of Umbilicaria; a consensus secondary structure of these introns is presented and we conclude that they represent an important and valuable molecular marker which gives additional support to the ITS and LSU sequence phylogeny obtained.