Lithocalla (Ascomycota, Lecanorales), a new genus of leprose lichens containing usnic acid

Abstract

The identity of Lecanora ecorticata has been uncertain due to conflicting reports of the presence of zeorin and the loss of the holotype. Phylogenetic analysis suggests that the species probably belongs in Ramalinaceae, where it is the first leprose species reported. Zeorin was found to be absent in recently collected material of L. ecorticata, including specimens from the type locality, and the report of zeorin in the lost holotype is considered to be due to contamination. A new genus, Lithocalla, is erected to accommodate L. ecorticata and a second closely related species, that occurs in the Falkland Islands, is newly combined as Lithocalla malouina. A lectotype is selected for L. ecorticata. Lithocalla is characterized by a leprose thallus containing usnic acid with fatty acids and terpenoids, but no zeorin; ascomata and conidiomata are unknown.

Pseudolepraria, a new leprose genus revealed in Ramalinaceae (Ascomycota, Lecanoromycetes, Lecanorales) to accommodate Lepraria stephaniana

“…However, this is only partly true, as some lichen groups with this type of thallus (e.g., species of Lepraria neglecta group) can grow also in other habitats (e.g., Laundon 1992 ; Lendemer 2013b ). Nevertheless, the statement of Poelt (1987) was true and innovative at this time and it was later shown that the leprarioid thallus indeed originated in several unrelated lichen lineages (e.g., Ekman and Tønsberg 2002 ; Kukwa and Pérez-Ortega 2010 ; Hodkinson and Lendemer 2013 ; Malíček et al 2018 ; Guzow-Krzemińska et al 2017 ; Orange 2020 ). Furthermore, some leprarioid genera are known exclusively in sterile state, like Andreiomyces ( Arthoniales , Arthoniomycetes ), Botryolepraria ( Verrucariales , Eurotiomycetes ), Lepraria and Lithocalla (both in Lecanorales , Lecanoromycetes ) ( Ekman and Tønsberg 2002 ; Kukwa and Pérez-Ortega 2010 ; Hodkinson and Lendemer 2013 ; Orange 2020 ).…”

“… Pseudolepraria is the first genus forming leprose and sterile thalli that can be placed with high support within Ramalinaceae . Orange (2020) described the genus Lithocalla and placed it with uncertainty in Ramalinaceae . In our phylogeny, Lithocalla forms the sister group to Ramalinaceae sensu Kistenich et al (2018) , but this may be an artifact of the taxon sampling.…”

“… Lithocalla was introduced for two species, which were originally placed, due to morphological similarities, in Lepraria , i.e., L. ecorticata (J. R. Laundon) Kukwa and L. malouina Øvstedal ( Kukwa 2006 ; Fryday and Øvstedal 2012 ). Both, Lithocalla ecorticata (J. R. Laundon) Orange known from Great Britain and Norway, and L. malouina (Øvstedal) Fryday & Orange found in the Falkland Islands ( Fryday and Øvstedal 2012 ; Orange 2020 ), differ from Pseudolepraria stephaniana , in their distribution in colder climates, by the production of usnic and fatty acids, the absence of zeorin and the exclusively saxicolous habitat ( Orange 2020 ).…”

“…For the phylogenetic analyses we used representatives of Ramalinaceae and Boreoplaca ultrafrigida Timdal and Ropalospora lugubris (Sommerf.) Poelt were used as outgroup taxa according to previous studies ( Kistenich et al 2018 ; Orange 2020 ; van den Boom and Magain 2020 ). The independent alignments for each marker were generated in MAFFT using auto option and default parameters ( Katoh and Standley 2013 ).…”

“…In contrast to their simplified morphology, the species produce a vast variety of secondary lichen metabolites, which are an invaluable tool, together with morphological characters that may be sparse, in the recognition of species and their identification (e.g., Laundon 1989 , 1992 ; Tønsberg 1992 ; Sipman 2004 ; Kantvilas and Kukwa 2006 ; Flakus and Kukwa 2007 ; Saag et al 2009 ; Flakus et al 2011a ; Lendemer 2011a , 2013a ; Lendemer and Hodkinson 2013 ; Guzow-Krzemińska et al 2019a ; Kukwa 2019 ). It is also noteworthy that some species until recently classified as Lepraria have been shown to belong to other genera (e.g., Leprocaulon and Septotrapelia Aptroot & Chaves; Bungartz et al 2013 ; Lendemer and Hodkinson 2013 ) or even new genera were established for some peculiar species, e.g., Andreiomyces Hodkinson & Lendemer within Arthoniomycetes ( Hodkinson and Lendemer 2013 ), Botryolepraria Canals et al, related to Verrucariaceae in Eurotiomycetes ( Kukwa and Pérez-Ortega 2010 ) and Lithocalla Orange in Lecanorales (probably in Ramalinaceae ) in Lecanoromycetes ( Orange 2020 ).…”