Remototrachyna, a newly recognized tropical lineage of lichens in the Hypotrachyna clade (Parmeliaceae, Ascomycota), originated in the Indian subcontinent

Abstract

Biogeographical studies of lichens used to be complicated because of the large distribution ranges of many species. Molecular systematics has revitalized lichen biogeography by improving species delimitation and providing better information about species range limitations. This study focuses on the major clade of tropical parmelioid lichens, which share a chemical feature, the presence of isolichenan in the cell wall, and a morphological feature, microscopic pores in the uppermost layer. Our previous phylogenetic studies revealed that the largest genus in this clade, Hypotrachyna, is polyphyletic with a clade mainly distributed in South and East Asia clustering distant from the core of the genus. To divide the Hypotrachyna clade into monophyletic groups and to reevaluate morphological and chemical characters in a phylogenetic context, we sampled ITS, nuclear large subunit (nuLSU) and mitochondrial small subunit (mtSSU) rDNA sequences from 77 species. We are erecting the new genus Remototrachyna for a core group of 15 former Hypotrachyna species. The segregation of Remototrachyna from Hypotrachyna receives support from morphological and chemical data, as well from maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses of the DNA. We used a likelihood approach to study the geographic range evolution of Remototrachyna and Bulbothrix, which are sister groups. This analysis suggests that the ancestral range of Remototrachyna was restricted to India and that subsequent long-distance dispersal is responsible for the pantropical occurrence of two species of Remototrachyna.

DNA barcode identification of lichen-forming fungal species in the Rhizoplaca melanophthalma species-complex (Lecanorales, Lecanoraceae), including five new species

“…In spite of the limitations in delimiting taxa using molecular data, the effective use of genetic data appears to be essential to appropriately and practically identify natural groups in some phenotypically cryptic lichen-forming fungal lineages (Divakar et al 2010b;Leavitt et al 2011b;Leavitt et al 2011c;Molina et al 2011b;Pino-Bodas et al 2011;Pino-Bodas et al 2012), including R. melanophthalma s.l. This does not preclude the fact that additional studies investigating morphological and chemical characters may potentially identify independent characters, or combinations of characters, supporting species circumscribed using molecular data.…”

Hypotrachyna penduliloba and Remototrachyna pandani, two new species in the hyperdiverse lichen family Parmeliaceae from Réunion in the Mascarene Archipelago

“…No prior values were assumed. Model selection was based on Divakar et al (2010Divakar et al ( , 2013. Four parallel runs were performed, each using four independent chains (three heated and one cold chain), with a single tree saved every 1000 th generation for a total of 6,000000 generations.…”

“…In overall morphology and chemistry, R. pandani closely resembles Hypotrachyna pseudosinuosa (Asahina) Hale and the two are likely to be easily confused. According to Divakar et al (2010) the major morphologicalanatomical character separating Remototrachyna from Hypotrachyna is the ascoma anatomy, especially the structure of the proper exciple (see also Ferencova 2012;Flakus et al 2012). Unfortunately H. pseudosinuosa seems to be very rarely fertile and the detailed anatomy of its apothecia is still unknown.…”

“…However, the morphological variability observed throughout its range may reflect cryptic speciation that requires further research (Louwhoff and Elix 2002;our observations). The loci ITS, nuLSU and mtSSU of two H. pseudosinuosa specimens from China were examined by Divakar et al (2010Divakar et al ( , 2013) and it appears that they belong to the Hypotrachyna sensu stricto clade; they are thus clearly distinct from the new species R. pandani. …”

Impact assessment of anthropogenic activities on air quality, using lichen Remototrachyna awasthii as biomonitor

“…Remototrachyna, broad lobed Asian Hypotrachyna clade, is a recent segregate and new genus described by Divakar et al (2010), which differs from Hypotrachyna clade in lobe morphology, rhizinae length, hymenium height, exciple structure and ascospore size. Broad lobed Remototrachyna has wide distribution in South and Southeast Asia and found to be frequently growing on twigs and trunks of Memecylon sp.…”