title: From one to six: unrecognized species diversity in the genus Acantholichen (lichenized Basidiomycota: Hygrophoraceae).
abstract: We present a taxonomic revision of the lichenized basidiomycete genus Acantholichen, species of which produce a characteristic blue-gray, microsquamulose thallus with spiny apical hyphal cells known as acanthohyphidia. Since its discovery, the genus was thought to be monospecific, only including the generic type, A. pannarioides. However, a detailed morphological and anatomical study of recently collected specimens from the Galápagos, Costa Rica, Brazil and Colombia, combined with a molecular phylogenetic analysis of the internal transcribed spacer (ITS1-5.8S-ITS2) region and 28S of the nuc rDNA and RPB2 sequences, revealed a much more diverse and widespread species assemblage. Based on the results of these analyses, we describe five new species in the genus: A. albomarginatus, A. campestris, A. galapagoensis, A. sorediatus and A. variabilis. We also provide an identification key to all species, anatomical and morphological descriptions, photographs and a table comparing main characters of each species.
authors.affiliation: Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia 22030-4444 manudalforno@hotmail.com.
authors.forename: Manuela
authors.initials: M
authors.lastname: Dal-Forno
authors.affiliation: Science & Education, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605, and Botanischer Garten und Botanisches Museum, Königin-Luise-Straße 6-8, 14195 Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Lücking
authors.affiliation: Biodiversity Assessment, Charles Darwin Foundation (AISBL), Puerto Ayora, Santa Cruz, Galápagos, Ecuador.
authors.forename: Frank
authors.initials: F
authors.lastname: Bungartz
authors.affiliation: Universidad Central del Ecuador, Quito, Ecuador.
authors.forename: Alba
authors.initials: A
authors.lastname: Yánez-Ayabaca
authors.affiliation: Instituto de Botânica, Núcleo de Pesquisa em Micologia, Av. Miguel Stéfano 3687, São Paulo/SP, CEP 04301-902, Brazil.
authors.forename: Marcelo P
authors.initials: MP
authors.lastname: Marcelli
authors.affiliation: Laboratório de Botânica/Liquenologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, CEP 79070-900, Campo Grande, Mato Grosso do Sul, Brazil.
authors.forename: Adriano A
authors.initials: AA
authors.lastname: Spielmann
authors.affiliation: Herbario Universidad de Caldas, Edificio Bicentenario, Manizales, A.A. 275, Caldas, Colombia.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Coca
authors.affiliation: Laboratorio de Hongos, Instituto Nacional de Biodiversidad, Santo Domingo de Heredia, Costa Rica.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Chaves
authors.affiliation: ABL Herbarium, G.v.d. Veenstraat 107, NL-3762 XK Soest, The Netherlands.
authors.forename: Andre
authors.initials: A
authors.lastname: Aptroot
authors.affiliation: Botanischer Garten und Botanisches Museum, Freie Universität, Königin-Luise-Straße 6-8, D-14195 Berlin, Germany.
authors.forename: Harrie J M
authors.initials: HJ
authors.lastname: Sipman
authors.affiliation: Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia 22030-4444.
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Sikaroodi
authors.affiliation: Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia 22030-4444.
authors.forename: Patrick
authors.initials: P
authors.lastname: Gillevet
authors.affiliation: Department of Biology, George Mason University, Fairfax, Virginia 22030-4444.
authors.forename: James D
authors.initials: JD
authors.lastname: Lawrey
mesh_terms: D001483:Base Sequence; D001487:Basidiomycota / Q000145:classification* / Q000166:cytology / Q000235:genetics; D001938:Brazil; D003105:Colombia; D003364:Costa Rica; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D014644:Genetic Variation; D008011:Lichens / Q000145:classification* / Q000166:cytology / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D005656:Fungal Proteins
keywords: Basidiolichens; lichenized fungi; montane forest; phylogeny; taxonomy; tropical diversity