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.