Species delimitation in the Lepraria isidiata-L. santosii group: a population study in the Mediterranean-Macaronesian region

Abstract

A thorough chemical, molecular and morphological study has been carried out on a problematic group in the genus Lepraria characterized by lobed, granular thalli with a raised rim and a preference for mosses, rocks and mineral soils in exposed, xeric habitats. The material examined was collected in seven countries of the Mediterranean-Macaronesian region, from chalk, carbonate rocks and derived soils (A-thalli), and from siliceous rocks and derived soils (B-thalli). The results of a phylogenetic analysis based on 93 ITS sequences (29 of which newly obtained) support the identification and the segregation of two taxa at species level, provisionally identified as Lepraria isidiata s. lat., (most of the A-thalli), and L. santosii s. lat. (B-thalli plus the remaining A-thalli), as the observed genetic variability is quite high. Three chemotypes were detected in L. isidiata s. lat., and seven in L. santosii s. lat. The two taxa are morphologically well characterized: in L. isidiata s. lat. the thallus is thicker and the propagules larger than in L. santosii s. lat. The first stages of thallus development from single propagules are described in both species. Some critical remarks are made about the increasing use of the species rank for taxa of Lepraria, which are morphologically and genetically scarcely characterized.

The genus Lepraria (Stereocaulaceae, lichenized Ascomycota) in Belarus

“…Since then, much attention has been paid to the taxonomy and chemistry of this group, and six species have been newly described, namely Orange and L. toensbergiana Bayerová & Kukwa (Tønsberg, 2002;Slavíková-Bayerová & Orange, 2006;Slavíková-Bayerová & Fehrer, 2007). However, the systematic position of the latter taxon has been briefly discussed (Bayerová & Haas, 2005;Baruffo et al, 2006;Fehrer et al, 2008;Tretiach et al, 2009;Saag et al, 2009), and a new combination L. jackii var. toensbergiana (Bayerová & Kukwa) Kukwa has been proposed (Śliwa & Kukwa, 2012).…”

Lichen Systematics: The Role of Morphological and Molecular Data to Reconstruct Phylogenetic Relationships

“…Chemical characters seem to be useful for the delimitation of species but do not reflect phylogenetic relationships within Lepraria (Ekman and Tønsberg 2002;Fehrer et al 2008;Nelsen and Gargas 2008). A species level study by Tretiach et al (2009), however, demonstrated considerable chemical variability within the two genetically and morphologically well-characterized species L. isidiata and L. santosii.…”

Perspectives on Chemotaxonomy: Molecular Data Confirm the Existence of Two Morphologically Distinct Species within a Chemically Defined Lepraria caesiella (Stereocaulaceae)

“…is one of the few groups of lichenized fungi where there have been multiple attempts to use molecular phylogenetic analyses to confirm the monophyly of species delineated by nonmolecular characters (Slaví-ková-Bayerová and Fehrer 2007, Fehrer et al 2008, Tretiach et al 2009, Lendemer 2011a. Interestingly, these previous studies of have produced conflicting results regarding the utility of chemotaxonomy.…”

“…Some studies have supported the use of chemical characters to delineate species (Slavíková-Bayerová and Fehrer 2007, Fehrer et al 2008. Others, however, have recovered well-supported monophyletic entities that were chemically variable (Tretiach et al 2009). Based on these studies it is clear that within Lepraria s.l., chemical characters alone cannot a priori be used to circumscribe monophyletic taxonomic entities.…”