Abstract

Two new species of Amanitasect.Phalloideae are described from tropical Africa (incl. Madagascar) based on both morphological and molecular (DNA sequence) data. Amanitabweyeyensissp. nov. was collected, associated with Eucalyptus, in Rwanda, Burundi and Tanzania. It is consumed by local people and chemical analyses showed the absence of amatoxins and phallotoxins in the basidiomata. Surprisingly, molecular analysis performed on the same specimens nevertheless demonstrated the presence of the gene sequence encoding for the phallotoxin phallacidin (PHA gene, member of the MSDIN family). The second species, Amanitaharkonenianasp. nov. was collected in Tanzania and Madagascar. It is also characterised by a complete PHA gene sequence and is suspected to be deadly poisonous. Both species clustered together in a well-supported terminal clade in multilocus phylogenetic inferences (including nuclear ribosomal partial LSU and ITS-5.8S, partial tef1-α, rpb2 and β-tubulin genes), considered either individually or concatenated. This, along with the occurrence of other species in sub-Saharan Africa and their phylogenetic relationships, are briefly discussed. Macro- and microscopic descriptions, as well as pictures and line drawings, are presented for both species. An identification key to the African and Madagascan species of Amanitasect.Phalloideae is provided. The differences between the two new species and the closest Phalloideae species are discussed.

Highlights

  • By comparing the tree topologies obtained for the individual datasets, no significant conflict, involving significantly supported nodes, was found using the 75% Maximum Likelihood (ML) BP criterion; the datasets were combined

  • The test of substitution saturation (Table 2) showed that the observed index of substitution saturation (Iss) for the ITS-LSU dataset (ITS and LSU partition considered individually) the tef-1, rpb2, LSU and β-tubulin alignments of the combined dataset was significantly lower than the corresponding critical index substitution saturation (Iss.c), indicating that there was little saturation in our sequences (P < 0.001)

  • The ring is smooth or vaguely plicate and the smell weak, resembling raw potato. We concluded that these two morphotypes / clades represent two distinct new species, which we describe below resp. as A. bweyeyensis sp. nov. and A. harkoneniana sp. nov

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Summary

Introduction

Are famous worldwide for their high, often deadly, toxicity. The section Phalloideae comprises nearly 60 described species, a number of which were described only recently, mainly from Asia (Li et al 2015, Cai et al 2016, Thongbai et al 2017). Based on a multigene analysis and morphological data, Cai et al (2014) identified 14 phylogenetic clades potentially representing new species. The phylogenetic analyses made by those authors resulted in the transfer of several species from sect.

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