Michael D. Guiry

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Verified

Michael verified their affiliation via an institutional email.

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• BSc, MSc, PhD, DSc, MRIA
• Professor Emeritus at Ollscoil na Gaillimhe – University of Galway

The recognition of new biological entities and the ability to give them a name is an intrinsic task of the taxonomist and contributes to the construction of a realistic inventory of the number of taxa in a flora or region. Mexico and Latin America have enormous algal resources, both marine and freshwater, and many taxa have yet to be discovered, wh...

The minute marine multicellular heterokont alga originally described as “ Giraudyopsis stellifer ” by P.J.L. Dangeard, nom. inval. , from Atlantic France, was re-isolated by the germling emergence technique and classified according to psa A and psb C sequences. It is genetically similar (99–100 % identity) to Phaeosaccion multiseriatum R.A. Anderse...

To date (1 November 2023), the online database AlgaeBase has documented 50,589 species of living algae and 10,556 fossil species here referred to four kingdoms (Eubacteria, Chromista, Plantae, and Protozoa), 14 phyla, and 63 classes. The algae are the third most speciose grouping of plant‐like after the flowering plants (≈382,000 species) and fungi...

Freshwater organisms in the Okavango Delta and Lake Ngami (Botswana) provide direct and indirect benefits to people and the economy of the region. However, their existence could be potentially threatened by human activities (primarily, upstream water abstraction and planned hydropower structures) coupled with climate change. For their protection, i...

Évaluation taxonomique de Pyropia hiemalis (Kylin) Varela-Álvarez, Guiry & Serrão, comb. nov. (Bangiaceae, Bangiophyceae). Jusqu'à récemment, tous les membres à lames des Bangiaceae Duby étaient assignés au genre Porphyra C.Agardh, nom. cons.; cependant, au cours des vingt dernières années, d'importantes révisions taxonomiques moléculaires de cette...

Simple Summary This inventory represents the first complete inventory of seaweeds (benthic brown, red, and green algae) and seagrasses from the Hawaiian Islands. We present taxonomic records compiled from the literature which include many recent descriptions of new species. Taxonomic records are accompanied by additional information allowing an ass...

Taxonomic, nomenclatural and distributional changes since the publication of the 2011 edition (reprinted 2021) of The Freshwater Algal Flora of the British Isles (“Flora”) are reviewed together with some changes overlooked earlier. Many of the more recent changes are a result of studies combining an analysis of morphological and DNA sequence data....

Cystoseira sensu lato (s.l.) – encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria – is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystos...

Certain conditions must be met to guarantee that the name of a species of algae is valid, under the International Code of Nomenclature of Algae, Fungi and Plants (Turland et al. 2018). Here is a list of requirements, such as an aid to validate the name of your species. The requirements are identical for subspecies, varieties and shapes. This summar...

Geologically recent radiations can shed light on speciation processes, but incomplete lineage sorting and introgressive gene flow render accurate evolutionary reconstruction and interpretation challenging. Independently evolving metapopulations of low dispersal taxa may provide an additional level of phylogeographic information, given sufficiently...

The genus Porphyra sensu lato (Bangiaceae, Rhodophyta), an important seaweed grown in aquaculture, is the most genetically diverse group of the Class Bangiophyceae, but has poorly understood genetic variability linked to complex evolutionary processes. Genetic studies in the last decades have largely focused on resolving gene phylogenies; however,...

The taxonomy of the genera Grateloupia, Phyllymenia and Prionitis has been revised several times but remains controversial. The female reproductive structure in combination with phylogenetic reconstructions are mostly used to define the genera. However, the architecture and behavior of the auxiliary cell ampullae before and after diploidization are...

A taxonomic list of macro marine algae (seaweeds) described in the literature for the Red Sea during the years 1756–2020 is presented. The list was prepared using existing published studies, local monitoring reports, as well as “grey” or unpublished lists of seaweeds for the area. Altogether, we examined more than 300 publications and compiled more...

Accurate species identification often relies on public repositories to compare the barcode sequences of the investigated individual(s) with taxonomically assigned sequences. However, the accuracy of identifications in public repositories is often questionable, and the names originally given are rarely updated. For instance, species of the Sea Lettu...

Sea Lettuce (Ulva spp. Ulvophyceae, Ulvaceae) has tremendous ecological and industrial impacts, from the negative effects of green tide events to the industrial production of food, feed, and value-added products. Due to the morphological similarities between Ulva species, their identification requires the use of “barcoding”, which relies on the seq...

The name Euastrum sinuosum Kützing [Kützing 1849: 174, ‘Euastrum (?) sinuosum’] is an illegitimate name as it included in synonymy “Cosmarium crenatum Ralfs” (Ralfs 1844: 394; Ralfs 1848: 96, pl. XV: fig. 7). Whilst Cosmarium crenatum Ralfs, 1844 is a devalidated name, it was validated as Cosmarium crenatum Ralfs ex Ralfs (Ralfs 1848: 96, pl. XV: f...

It has come to our attention that six proposed transfers in Siqueiros Beltrones & al. (2017) of Navicula Bory taxa to Lyrella Karayeva did not meet the requirements of ICN Art. 41.5 (ShenzhenCode, Turland & al. 2018) as a full and direct reference given to its author and place of valid publication, with page or plate reference and date, were not in...

Sea Lettuce (Ulva spp.; Ulvophyceae, Ulvales, Ulvaceae) is an important ecological and economical entity, with a worldwide distribution and is a well-known source of near-shore blooms blighting many coastlines. Species of Ulva are frequently misiden-tified in public repositories, including herbaria and gene banks, making species identification base...

Foliose Ulva spp. have become increasingly important worldwide for their environmental and financial impacts. A large number of such Ulva species have rapid reproduction and proliferation habits, which explains why they are responsible for Ulva blooms, known as “green tides”, having dramatic negative effects on coastal ecosystems, but also making t...

The brown algal genus Cladostephus (Sphacelariales) is found worldwide in temperate regions. Two species are considered endemic to South America (C. antarcticus Kützing and C. hariotii Sauvageau), whilst specimens from the rest of the world are usually attributed to a third, cosmopolitan species, C. spongiosus (Hudson) C.Agardh. However, comparison...

Marine phytoplankton are responsible for half of the global net primary production and perform multiple other ecological functions and services of the global ocean. These photosynthetic organisms comprise more than 4300 marine species, but their biogeographic patterns and the resulting species diversity are poorly known, mostly owing to severe data...

The chrysophycean genus Lepidochromonas Kristiansen was established to accommodate a single species, Ochromonas diademifera E. Takah. characterized by cells covered by both plate-like scales and crown-shaped scales. Subsequently Lepidochromonas has been synonymized with Paraphysomonas De Saedeleer. Currently, the genus Paraphysomonas is restricted...

Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests...

Next Generation Sequencing (NGS) technologies allow for the generation of robust information on the genetic diversity of organisms at the individual, species and higher taxon levels. Indeed, the number of single nucleotide polymorphisms (SNPs) detected using next-generation sequencing is order of magnitudes higher than SNPs and/or alleles detected...

RbcL sequence analyses of Gelidium divaricatum-like specimens—mat-forming, small red algae—based on new collections from Hong Kong revealed at least three different natural lineages: two align to the current concept of the genus Gelidium (Clades I & II) and one to Gelidiophycus (Clade III). The gross morphology of the specimens in Clade I fit close...

The green algal genus Ostreobium is an important symbiont of corals, playing roles in reef decalcification and providing photosynthates to the coral during bleaching events. A chloroplast genome of a cultured strain of Ostreobium was available, but low taxon sampling and Ostreobium's early-branching nature left doubt about its phylogenetic position...

We present a consensus classification of life to embrace the more than 1.6 million species already provided by more than 3,000 taxonomists' expert opinions in a unified and coherent, hierarchically ranked system known as the Catalogue of Life (CoL). The intent of this collab-orative effort is to provide a hierarchical classification serving not onl...

The Pacific Island region is an ideal setting for case studies on the invasion history of macroalgae in tropical coastal waters. Many textbook examples of algal invasions in this region demonstrate their significant ecological impacts on native reef communities. In light of increased maritime traffic as a potential anthropogenic dispersal mechanism...

Anadyomene stellata (Wulfen) C.Agardh (Anadyomenaceae, Chlorophyta), a vagrant new to Britain Paul Gainey 14, Polwithen Road, Penryn, Cornwall, TR10 8QT, UK Michael Guiry AlgaeBase, Ryan Institute, NUI Galway, Galway H91 TK33, Ireland David Fenwick 84 Roscadghill Parc, Penzance, Cornwall, TR18 3QY, UK Alan Alder UK Vagrancy is not a term that has...

In the third part of his monumental monograph of the Nostocaceae, Komárek included Nostoc flagelliforme, a widely distributed soil species consumed in some part of the world, crediting the name to “Berkeley et Curtis ex Bornet et Flahault 1888”. However, the name was not introduced at the species level by Bornet & Flahault. Instead, the name valida...

A revision of the check-list of the red (Rhodophyta), green (Chlorophyta) and brown (Ochrophyta, Phaeophyceae) seaweeds of Britain has been compiled and revealed 644 taxa, mostly at species level but including infraspecific taxa: 348 reds, 110 greens and 186 browns. There were 30 additions to the list, notably five newly described species and five...

Background: Reliable taxonomy underpins communication in all of biology, not least nature conservation and sustainable use of ecosystem resources. The flexibility of taxonomic interpretations, however, presents a serious challenge for end-users of taxonomic concepts. Users need standardised and continuously harmonised taxonomic reference systems,...

Specimens of a seaweed sent to Sir Joseph Banks in England at the beginning of the nineteenth century by a collector in China were described as a new species, Fucus tenax, by the English botanist and antiquarian Dawson Turner. This seaweed has been extensively used in Japan, China and Korea as a source of glue and gum and has been more recently emp...

[This corrects the article DOI: 10.1371/journal.pone.0119248.].

Proposed hierarchical classification from superkingdom to order. (XLSX)

The common brown alga Scytosiphon lomentaria (Scytosiphonaceae) has generally been regarded as a species complex. In the Pacific, molecular data have shown that it includes more than one species; the diversity in other oceans, however, has not been examined. In the present study, the genetic diversity of S. lomentaria was investigated in 57 samples...

We present a consensus classification of life to embrace the more than 1.6 million species already provided by more than 3,000 taxonomists' expert opinions in a unified and coherent, hierarchically ranked system known as the Catalogue of Life (CoL). The intent of this collab-orative effort is to provide a hierarchical classification serving not onl...

Photosynthetic eukaryotes have a critical role as the main producers in most ecosystems of the biosphere. The ongoing environmental metabarcoding revolution opens the perspective for holistic eco-systems biological studies of these organisms, in particular the unicellular microalgae that often lack distinctive morphological characters and have comp...

The marine red algal family Liagoraceae sensu lato is shown to be polyphyletic based on analyses of a combined rbcL and psaA dataset and the pattern of carposporophyte development. Fifteen of eighteen genera analyzed formed a monophyletic lineage that included the genus Liagora. Nemalion did not cluster with Liagoraceae sensu stricto, and Nemaliace...

Gigartina acicularis is an intertidal, perennial red alga which reaches its northern distributional limit in the north-eastern Atlantic on the Irish coast. It has only rarely been found with reproductive structures in the British Isles. Plants isolated vegetatively from field-collected plants near the northern distributional limit in Ireland formed...

Table S1. Collection data and GenBank accession numbers of the samples of Prasiolales for which new sequences were produced in the study. Moniz M.B.J., Guiry M.D., Rindi F. (2014). tufA phylogeny and species boundaries in the green algal order Prasiolales (Trebouxiophyceae, Chlorophyta). Phycologia: 53 (4): 396-406.

The order Prasiolales is one of the most characteristic lineages of the green algal class Trebouxiophyceae. Although its phylogeny has been studied in detail in recent years, several important features of its systematics and taxonomy are still in need of clarification. We investigated the phylogeny of the tufA gene in the Prasiolales, a marker that...

In development since 1996, AlgaeBase (http://www.algaebase.org) is an on-line database providing free access to authoritative taxonomic, distributional and nomenclatural information of more than 135,000 names of species and infraspecific taxa of algae set in the context of a taxonomic hierarchy. The project was initially funded by the Higher Educat...

The roles of Biological Resource Centres (BRCs), such as the Culture Collection of Algae and Protozoa (CCAP), have extended beyond their traditional maintenance and provision of curated microorganisms to the user community. A major driver for change has been the exponential increase in metagenomics and environmental sequencing data over the last fe...

Ireland has a long history of seaweed utilisation, with accounts of its use as a food dating to at least the twelfth century. Arramara Teoranta (literally “Seagoods Ltd.”) was established by the Irish Government in the late 1940s to continue the long tradition of sustainable seaweed harvesting in the west of Ireland, which began with kelp ash produ...

The widespread view of taxonomy as an essentially retrogressive and outmoded science unable to cope with the current biodiversity crisis stimulated us to analyze the current status of cataloguing global algal diversity. Contrary to this largely pessimistic belief, species description rates of algae through time and trends in the number of active ta...

The conjugating algae, an almost exclusively freshwater and extraordinarily diverse group of streptophyte green algae, are referred to a class generally known as the Conjugatophyceae in Central Europe and the Zygnematophyceae elsewhere in the world. Conjugatophyceae is widely considered to be a descriptive name and Zygnematophyceae ('Zygnemophyceae...

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be disco...

The existing literature on phototropism in marine macroalgae is reviewed. A phototropic response is a sequence of three different processes: reception of the directional light signal; transformation of the signal to a physiological response (transduction); and the production of directional growth response. The only available information about the p...

As defined in the broadest sense, algae are oxygen-generating, photosynthetic organisms other than embryophyte land plants and lichens (Cavalier-Smith, T. 2007. Evolution and relationships of algae: major branches of the tree of life. In Unravelling the algae: the past, present and future of algal systematics, eds. Brodie, J. and Lewis J, pp. 21–55...

Algae have been estimated to include anything from 30,000 to more than 1 million species. An attempt is made here to arrive at a more accurate estimate using species numbers in phyla and classes included in the on‐line taxonomic database AlgaeBase (http://www.algaebase.org). Despite uncertainties regarding what organisms should be included as algae...

Trebouxiophytes of the genus Prasiola are well known in Antarctica, where they are among the most important primary producers. Although many aspects of their biology have been thoroughly investigated, the scarcity of molecular data has so far prevented an accurate assessment of their taxonomy and phylogenetic position. Using sequences of the chloro...

A collection of Laminariales species was made with examples in each of the presently recognized families of the order. Extracts of each species were examined for betaines, using primarily 'H NMR spectroscopy for their identification. Glycinebetaine was detected in all species tested and would appear to be a consistent feature of the Laminariales. G...

Phlorotannins have received much attention due to their ecophysiological importance and potential applications in the biotechnology and food industries. Antioxidant activity studies in seaweeds have mainly focused on in vitro assays; however, there is a paucity of data regarding the effect of brown algal phlorotannins on living cultured cells. The...

The order Prasiolales includes trebouxiophycean green algae widely distributed in polar and cold temperate regions. Molecular data produced in recent years have shed considerable light on the phylogeny and genetic diversity of this group. Most of the information available for the order, however, has been obtained for the northern hemisphere; inform...

Trebouxiophytes of the genus Prasiola are well known in Antarctica, where they are among the most important primary producers. Although many aspects of their biology have been thoroughly investigated, the scarcity of molecular data has so far prevented an accurate assessment of their taxonomy and phylogenetic position. Using sequences of the chloro...

Cyanobacteria (= blue-green algae) are prolific producers of structurally distinct and biologically active metabolites. In the continuation of our search for new sources of anti-infective natural products, we have assessed the in vitro antiprotozoal (Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani) and antituber...

Chondrus crispus has a sexual life history of the Polysiphonia type and spores other than carpospores and tetraspores have not previously been reported. Several cultures of male plants from widely separated geographic locations have now been observed to produce large masses of spores in structures that superficially resemble cystocarps but whose or...

In the continuation of our research on seaweeds, crude extracts of 21 brown algae collected from the south coast of England and the west coast of Ireland were screened for in vitro trypanocidal, leishmanicidal and antimycobacterial activities. Mammalian stages of a small set of parasitic protozoa; i.e. Trypanosoma brucei rhodesiense, T. cruzi and L...

Inferring how the Pleistocene climate oscillations have repopulated the extant population structure of Chondrus crispus Stackh. in the North Atlantic Ocean is important both for our understanding of the glacial episode promoting diversification and for the conservation and development of marine organisms. C. crispus is an ecologically and commercia...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

As part of our continuing research on seaweeds, we have screened the crude extracts of 23 red marine algae collected from England and Ireland. The clinically important blood-stage life forms of Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and Mycobacterium tuberculosis were used as test organisms in the in vitro assays. The selecti...