A morphological and phylogenetic evaluation of Marasmius sect. Globulares (Globulares-Sicci complex) with nine new taxa from the Neotropical Atlantic Forest

Abstract

The largest and most recently emended Marasmius sect. Globulares (Globulares-Sicci complex) has increased in number of species annually while its infrasectional organization remains inconclusive. During forays in remnants of the Atlantic Rainforest in Brazil, 24 taxa of Marasmius belonging to sect. Globulares were collected from which nine are herein proposed as new: Marasmius altoribeirensis, M. ambicellularis, M. hobbitii, M. luteoolivaceus, M. neotropicalis, M. pallidibrunneus, M. pseudoniveoaffinis, M. rhabarbarinoides and M. venatifolius. We took this opportunity to evaluate sect. Globulares sensu Antonín & Noordel. in particular, combining morphological examination and both single and multilocus phylogenetic analyses using LSU and ITS data, including Neotropical samples to a broader and more globally distributed sampling of over 200 strains. Three different approaches were developed in order to better use the genetic information via Bayesian and Maximum Likelihood analyses. The implementation of these approaches resulted in: i) the phylogenetic placement of the new and known taxa herein studied among the other taxa of a wide sampling of the section; ii) the reconstruction of improved phylogenetic trees presenting more strongly supported resolution especially from intermediate to deep nodes; iii) clearer evidence indicating that the series within sect. Sicci and sect. Globulares in the traditional concept are non-monophyletic by this more stringent evaluation; and iv) the existence of several monophyletic suprespecific groups equivalent to the stirpes of Singer – clusters of morphologically similar species. These two latter points corroborate with findings of previous studies implementing analyses with the entire genus. Based on these results, we proposed a new infrasectional classification elevating Singer's concept of stirpes to series. Thirteen new series, the emendation of three extant series and three subsections gathering these series based on the major clades are proposed.

Global distribution and richness of Armillaria and related species inferred from public databases and amplicon sequencing datasets

“…Additionally, the relatively characteristic signs of Armillaria presence in the environment, including white mycelial fans under tree bark and black shoestring-like rhizomorphs (Baumgartner et al, 2011) are easy to identify, collect, culture, and sequence species of Armillaria , which certainly aids in our understanding of the distribution of these species even in the absence of sporocarps. Lastly, the entirety of the armillarioid clade has relatively few species when compared to other genera found in the Agaricales (Liimatainen et al, 2014; Oliveira et al, 2020). Of course, the available community sequencing studies from which we mined do not comprehensively represent all natural communities in which armillarioid species occur, so there are undoubtedly more species that are left to be found as sampling increases.…”

Marasmius magnus (Marasmiaceae, Basidiomycota) en Argentina

“…La secuencia obtenida fue ensamblada y editada manualmente utilizando el software Geneious 9.1.4 (Kearse et al, 2012) y depositada en la base de datos del Genbank. Para la construcción de la matriz, se seleccionaron las secuencias más afines (90-100 % de similitud y e-value = 0.0) a través de la herramienta BLAST (Basic Local Alignment Search Tool), sumado a las secuencias pertenecientes a la sección Globulares, subsección Globulares de acuerdo a los criterios determinados por Oliveira et al (2020) (Oliveira et al, 2020). Todas las secuencias utilizadas en este estudio se listan en la Tabla 1.…”

“…La matriz incluyó 47 secuencias pertenecientes a 12 taxones clasificados dentro de la sección Globulares subsección Globulares, más el grupo externo (Oliveira et al, 2020). El alineamiento resultó en un total de 817 caracteres, de los cuales 533 eran sitios conservados, 267 variables y 201 parsimonioso-informativos.…”

“…Set de datos de secuencias de ITS de Marasmius utilizadas en los análisis filogenéticos, clasificadas por grupos infragenéricos ss. Oliveira et al (2020). El doble guión (--) indica que esa especie no fue asignada a ninguna serie.…”

“…El doble guión (--) indica que esa especie no fue asignada a ninguna serie. Las secuencias disponibles en GenBank se encuentran en: a, Oliveira et al (2020); b, Razaq et al (2013); c, Wannathes et al (2009); d, Antonín et al (2010); e, Kiyashko et al (2014); f, Magnago et al (2016); g, Este estudio; h, Seok et al (GanBank); i, Matheny et al (2006); j, Boskovic & Galovic (GenBank); k, Wang et al (2015); l, Schoch et al (2012); m, Antonín et al (2014).…”