New insights into the phylogeny and relationships within the worldwide genus Riccardia (Aneuraceae, Marchantiophytina)

Abstract

Abstract. With 280 accepted species, the genus Riccardia S.F.Gray (Aneuraceae) is one of the most speciose genera of simple thalloid liverworts. The current classification of this genus is based on morphological and limited-sampling molecular studies. Very few molecular data are available and a comprehensive view of evolutionary relationships within the genus is still lacking. A phylogeny focusing on relationships within the large genus Riccardia has not been conducted. Here we propose the first worldwide molecular phylogeny of the genus Riccardia, based on Bayesian inference and parsimony ratchet analyses of sequences from three plastid regions (psbA-trnH, rps4, trnL-F). The results support the monophyly of Riccardia and a new monospecific genus, Afroriccardia Reeb & Gradst. gen. nov., is described based on molecular and morphological evidence. The results indicate that several currently recognized infrageneric divisions and a few species are not monophyletic, suggesting that further analyses are needed to arrive at a proper understanding of the phylogeny of the genus. Although evidence for an Andean clade was found, most of the species appear scattered in different clades without clear geographical segregation. Broader sampling and further analyses are necessary in order to improve our understanding of the phylogeny of this poorly known liverwort genus.

Riccardia verticillata Gradst. & Reeb, a new dendroid species of Riccardia (Aneuraceae) from the Cordillera del Cóndor, Ecuador

“…Material of the new species, collected by CP, NZ and AJP during the 2019 botanical exploration of the El Quimi Reserve, was studied by SRG and CR using traditional anatomical and morphological methods (e.g., Rabeau et al 2017;Gradstein and Reeb 2018).…”

Quantification of complex modular architecture in plants

“…In total, 183 collections from the 10 Riccardia species currently reported from sub‐Saharan Africa (Reeb & Bardat, ) were sampled for molecular species delimitation (Table S1). Collections of Aneura (11), the sister genus to Riccardia (Preußing et al ., ), and six collections of the newly segregated genus Afroriccardia (Rabeau et al ., ) were selected as outgroups.…”

The distribution and evolution of fungal symbioses in ancient lineages of land plants

“…Basidiomycota and Ascomycota symbioses appear to have been gained and lost multiple times during the evolution of the Metzgeriidae and Jungermanniidae. In the Metzgeriidae, there was a single gain of Basidiomycota symbiosis within the Aneuraceae and a subsequent loss from a large number of the later-diverging Riccardia species (Rabeau et al 2017). Because the fungal symbiosis status of many Jungermanniidae families remains unresolved, it is not yet possible to accurately estimate gains and losses of Ascomycota and Basidiomycota symbioses in this subclass.…”