Taxonomy and systematics of Hyaloscyphaceae and Arachnopezizaceae

Abstract

<p>The circumscription and composition of the <em>Hyaloscyphaceae</em> are controversial and based on poorly sampled or unsupported phylogenies. The generic limits within the hyaloscyphoid fungi are also very poorly understood. To address this issue, a robust five-gene Bayesian phylogeny (LSU, <em>RPB1</em>, <em>RPB2</em>, <em>TEF-1α</em>, mtSSU; 5521 bp) with a focus on the core group of <em>Hyaloscyphaceae</em> and <em>Arachnopezizaceae</em> is presented here, with comparative morphological and histochemical characters. A wide representative sampling of <em>Hyaloscypha</em> supports it as monophyletic and shows <em>H. aureliella</em> (subgenus <em>Eupezizella</em>) to be a strongly supported sister taxon. Reinforced by distinguishing morphological features, <em>Eupezizella</em> is here recognised as a separate genus, comprising <em>E. aureliella</em>, <em>E. britannica</em>, <em>E. roseoguttata</em> and <em>E. nipponica</em> (previously treated in <em>Hyaloscypha</em>). In a sister group to the <em>Hyaloscypha-Eupezizella</em> clade a new genus, <em>Mimicoscypha</em>, is created for three seldom collected and poorly understood species, <em>M. lacrimiformis</em>, <em>M. mimica</em> (<em>nom. nov.</em>) and <em>M. paludosa</em>, previously treated in <em>Phialina</em>, <em>Hyalo­scypha</em> and <em>Eriopezia</em>, respectively. The <em>Arachnopezizaceae</em> is polyphyletic, because <em>Arachnoscypha</em> forms a monophyletic group with <em>Polydesmia pruinosa</em>, distant to <em>Arachnopeziza</em> and <em>Eriopezia</em>; in addition, <em>Arachnopeziza variepilosa</em> represents an early diverging lineage in <em>Hyaloscyphaceae</em> s.str. The hyphae originating from the base of the apothecia in <em>Arachnoscypha</em> are considered anchoring hyphae (vs a subiculum) and <em>Arachnoscypha</em> is excluded from <em>Arachnopezizaceae</em>. A new genus, <em>Resinoscypha</em>, is established to accommodate <em>Arachnopeziza variepilosa</em> and <em>A. monoseptata</em>, originally described in <em>Protounguicularia</em>. <em>Mimicoscypha</em> and <em>Resinoscypha</em> are distinguished among hyaloscyphoid fungi by long tapering multiseptate hairs that are not dextrinoid or glassy, in combination with ectal excipulum cells with deep amyloid nodules. Unique to <em>Resinoscypha</em> is cyanophilous resinous content in the hairs concentrated at the apex and septa. Small intensely amyloid nodules in the hairs are furthermore characteristic for <em>Resinoscypha</em> and <em>Eupezizella</em>. To elucidate species limits and diversity in <em>Arachnopeziza</em>, mainly from Northern Europe, we applied genealogical concordance phylogenetic species recognition (GCPSR) using analyses of individual datasets (ITS, LSU, <em>RPB1</em>, <em>RPB2</em>, <em>TEF-1α</em>) and comparative morphology. Eight species were identified as highly supported and reciprocally monophyletic. Four of these are newly discovered species, with two formally described here, viz. <em>A. estonica</em> and <em>A. ptilidiophila</em>. In addition, <em>Belonium sphagnisedum</em>, which completely lacks prominent hairs, is here combined in <em>Arachnopeziza</em>, widening the concept of the genus. Numerous publicly available sequences named <em>A. aurata</em> represent <em>A. delicatula</em> and the confusion between these two species is clarified. An additional four singletons are considered to be distinct species, because they were genetically divergent from their sisters. A highly supported five-gene phylogeny of <em>Arachnopezizaceae</em> identified four major clades in <em>Arachnopeziza</em>, with <em>Eriopezia</em> as a sister group. Two of the clades include species with a strong connection to bryophytes; the third clade includes species growing on bulky woody substrates and with pigmented exudates on the hairs; and the fourth clade species with hyaline exudates growing on both bryophytes and hardwood. A morphological account is given of the composition of <em>Hyaloscyphaceae</em> and <em>Arachnopezizaceae</em>, including new observations on vital and histochemical characters.<br /></p>