Biogeography of aquatic hyphomycetes: Current knowledge andfuture perspectivesSoa Duarte a, *, Felix Barlocher b, Cl

audia Pascoal a, Fernanda C

assio aaCentre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho Campus de Gualtar, 4710-057 Braga, PortugalbDepartment of Biology, Mount Allison University, Sackville, New Brunswick E4L 1G7, Canadaarti cle i nfoArticle history:Received 2 March 2015Received in revised form26 May 2015Accepted 5 June 2015Available online xxxKeywords:Aquatic hyphomycetesBiogeographyPhylogeographyMetagenomicsMorphospeciesGenetic diversityNext-generation sequencingabstractSince Ingold's (1942) initial description, mycologists have been interested in deciphering global distri-bution patternsofaquatichyphomycetes, agroupoffungithatplay akeyroleinplant-litter decom-position in freshwaters. However, many questions remain largely unanswered. In this review, we useddistributiondata of morphospecies from studiesthroughout the world in an attempt to better under-standthemagnitudeofglobalspeciesrichness, patternsofbiodiversity andtheextentofcosmopoli-tanismversus endemism. Sampling efforts have varied among geographic regions, and correlatesignicantly with species richness. Community similarity decreased with geographic or latitudinal dis-tance. Speciesrichnesswashighestatmid-latitudes(temperatestreams), andhighcommunitysimi-larities were found between geographically distant locations in similar climatic zones. Studies relying onmorphotypes have undoubtedly provided relevant information on the geographic distribution of aquatichyphomycetes. However, metagenomicapproaches combining taxonomic,phylogenetic and functionaldiversityincoordinatedsurveyswillbethebestoptionto better decipherdiversitypatternsofthesefungi and their functional roles at a global scale. 2015 Elsevier Ltd and The British Mycological Society. All rights reserved.1. IntroductionFungi are widely distributed across all biomes and play a majorrole in the recycling of organic matter with more than 600 speciesreported from freshwaters (Wong et al., 1998; Shearer et al., 2007).Ingoldianfungioraquatichyphomycetesaboundin well-aeratedwaters and are regarded as the dominant microbial decomposersof leaves decaying in streams (B arlocher, in this issue). Members ofthisecologicallydenedgroupregularlysporulateunderwater,and have large conidia (often spanning more than 50mm) of twopredominant shapes: branchedandoftentetraradiateor multi-radiate(stauroid), andsigmoidor worm-like(scolecoid) (Guliset al., 2005; Shearer et al., 2007) (Fig. 1). Much of our knowledgeonaquatichyphomycetediversityinfreshwatersemergesfromspecies classication based on their characteristic conidial shapes.Though slightly heavier than water, conidia are readily trapped infoam or scum, which accumulates in streams (Ingold, 1975). Con-idiacanalsobesampledfromthewatercolumnbyltrationorfrom naturally colonized submerged substrata (e.g. leaves,twigs)andsubstratebaitsafterinducingsporulationinthelaboratory(Gulis et al., 2005).De Wildeman (1893, 1894, 1895) was the rst to recognize someof the typical conidial forms of aquatic hyphomycetes anddescribedspeciesofseveralgenera(Clavariopsis, LemonnieraandTetracladium) (Fig. 1). However, these fungi only gained relevancenearly half a century later when Ingold (1942) described 16 forms ofconidia and traced themback to mycelia on decaying alder leaves inastreamnearLeicester, inEngland. Intherstof manypapersdevotedtoaquatichyphomycetes, Ingold(1942)wrote: Myob-servations on aquatic hyphomycetes have been limited,so far,tothe immediate neighbourhood of Cropston in Leicestershire, but itis of interest to knowif they are of wide occurrence. In subsequentyears, he found identical or similar spores in samples from manyregions in Britain (Ingold, 1943a,b), and other parts of the world,including Europe (e.g. Switzerland: Ingold, 1949),Africa (Nigeria:Ingold, 1956, 1959; Uganda and Zimbabwe: Ingold, 1958;Swaziland: Ingold, 1973), North America (Canada: Ingold, 1960) andCaribbeanIslands(e.g. Jamaica: HudsonandIngold, 1960), thusdemonstratingtheworld-wideoccurrenceof aquatichyphomy-cetes. Studiesbyotherresearchersconrmedtheirglobaldistri-bution (e.g. California: Ranzoni, 1953; Japan: Tubaki, 1957; eastern *Corresponding author.E-mail address: [email protected] (S. Duarte).Contents lists available at ScienceDirectFungal Ecologyj ournal homepage: www. el sevi er. com/ l ocat e/ f unecohttp://dx.doi.org/10.1016/j.funeco.2015.06.0021754-5048/ 2015 Elsevier Ltd and The British Mycological Society. All rights reserved.Fungal Ecology xxx (2015) 1e10Please cite this article in press as: Duarte, S., et al., Biogeography of aquatic hyphomycetes: Current knowledge and future perspectives, FungalEcology (2015), http://dx.doi.org/10.1016/j.funeco.2015.06.002 USA: Petersen1962, 1963a,b; Scandinavia: Nilsson, 1958, 1964;South Africa: Greathead, 1961; Australia: Cowling and Waid, 1963;Cuba: Marvanova and Marvan, 1969 and Malaysia: Nawawi, 1985).Comparedtootherfreshwaterfungi, thedistributionof aquatichyphomycetes is relatively well studied and several data compila-tions exist based on morphospecies (taxonomy based on morpho-logical differences of the conidia) (e.g. Ingold, 1975; Webster andDescals, 1981; Marvanov a, 1997; Santos-Flores andBetancourt-L opez, 1997;Gulisetal., 2005), althoughstudiesintropicallati-tudes have been less common (e.g. Sridhar et al., 1992; Goh, 1997;Marvanova, 1997). Comparablecommunities exist intemperatezones on both sides of the equator; streams closer to the equatorare represented by a characteristic tropical mycoora, whichnevertheless contains many species common to temperate zones(Wood-Eggenschwiler and B arlocher, 1985). In fact, many species ofaquatic hyphomycetes have been found in streamfoam collected indifferentpartsof theworld(Ingold, 1975;WebsterandDescals,1981), suggestingthatthedistributionof aquatichyphomycetesmight followthe hypothesis of Baas Becking (1934). This hypothesispostulates, withrespect tomicrobes, that everythingisevery-whereandthatsmall organisms(