The genus Agaricus in the Caribbean. Nine new taxa mostly based on collections from the Dominican Republic

Abstract

Field collections of Agaricus were collected in the Dominican Republic from 2009–2016 with the intent to evaluate the diversity in this genus, which was quasi-unknown in this country. In the same period, studies on tropical Agaricus revealed tropical clades that remained unclassified. A new taxonomic system of classification was developed, with the aim, inter alia, to integrate such tropical clades. A recent phylogenetic study, which included some samples from the Dominican Republic, revealed they belonged to three putative new sections. Our objective in this paper is to describe the species of Agaricus collected in this country and to classify them whitin the new taxonomic system, including formal descriptions of the three new sections to which they belong. A preliminary study indicated that the collections of the Dominican Republic belong either to a group of three related subgenera (Flavoagaricus, Minores, and Minoriopsis) or to the unrelated A. subg. Pseudochitonia. For the species of the three related subgenera, a phylogenetic analysis based on ITS sequences data reliably confirmed the classification of the species into five sections including the three new sections, which were well supported. For the collections of A. subg. Pseudochitonia, preliminary studies indicated that they all belonged to species of A. sect. Xanthodermatei without any doubt except for one species. This species was included in a multi-gene (ITS, LSU and tef-1α) phylogenetic analysis which confirmed placement in this section. Consequently, all the samples were included in a phylogenetic analysis based on ITS sequences and focusing on A. sect. Xanthodermatei. We noted an unusually high intraspecific variability in the ITS sequences of five of the 12 studied species. Fifteen taxa are described, among which three sections and six species are new for science: Agaricus sect. Kerrigania, Agaricus sect. Minoriopsis, Agaricus sect. Pantropicales, A. argenteopurpureus, A. candussoi, A. flavidodiscus, A. lodgeae, A. porphyropos and A. tephrolepidus. We report all these taxa from the Dominican Republic but the latter three species are also recorded from Puerto Rico, United States Virgin Islands, and Mexico, respectively.

A new section and species of Agaricus subgenus Pseudochitonia from Thailand

“… angusticystidiatus . Thus up to now, there are six subgenera and 24 sections in the genus Agaricus ( Zhao et al 2016 ; Chen et al 2017 ; Parra et al 2018 ).…”

“…That means divergence time has been used as an additional criterion to rank taxa of above species level in Agaricus . Later, the criterion of divergence time, along with phylogenetic, monophyletic and morphological support, has been accepted in other new subgenus and section recognitions in Agaricus , such as a new subgenus Minoriopsis ( Chen et al 2017 ); and a new section Kerrigania ( Parra et al 2018 ).…”

“…In that study, Agaricus was segregated into five subgenera and 20 sections, according to the phylogenetic position and divergence time of each clade. With the recent discovery of an American subgenus and a new clade found in the Caribbean area, Agaricus now contains six subgenera and 23 sections ( Zhao et al 2016 , Chen et al 2017 , Parra et al 2018 ).…”

Outstanding Pinkish Brown-Spored Neotropical Boletes:Austroboletus subflavidusandFistulinella gloeocarpa(Boletaceae, Boletales) from the Dominican Republic

“…(Caesalpinoideae), which represent its possible ECM host trees. See Parra et al [107] for further details on lowland vegetation in the Dominican Republic. Apparently localized in the Dominican Republic.…”

Neoboletus antillanus sp. nov. (Boletaceae), first report of a red-pored bolete from the Dominican Republic and insights on the genus Neoboletus

“…solitary to gregarious, growing on limestone among litter in a seasonally dry and moist anthropised lowland mixed stand under a large array of neotropical broadleaved trees, including Coccolobauvifera , which represents its probable ECM host tree. See Parra et al (2018) for further details on vegetation.…”