Myriam de Haan

• BSc
• Researcher at Meise Botanic Garden

Background: The first records of Protosteloid Amoebae in the Democratic Republic of the Congo are discussed in the present paper. This survey on Protosteloid Amoebae is the first from Central African; the previous records for the African continent were restricted to Egypt, Kenya, Malawi, Tanzania and Uganda. Methods: Aerial litter samples, collecte...

Through the publication in 2004 of the new species Physarum squamosum Flatau & Schirmer (Physaraceae, Myxomycetes, Eumycetozoa) two Belgian collections could finally be identified. The first collection dates from November 1994 and was made in Zoerselbos(Zoersel, Province of Antwerp) on dead bramble stem( Rubus sp.). The second one was made in Novem...

Protecting aboveground carbon stocks in tropical forests is essential for mitigating global climate change and is assumed to simultaneously conserve biodiversity. Although the relationship between tree diversity and carbon stocks is generally positive, the relationship remains unclear for consumers or decomposers. We assessed this relationship for...

Myxomycetes (also called Myxogastria or colloquially, slime moulds) are worldwide occurring soil amoeboflagellates. Among Amoebozoa, they have the notable characteristic to form, during their life cycle, macroscopic fruiting bodies, that will ultimately release spores. Some 1,000 species have been described, based on the macroscopic and microscopic...

About a thousand described species of Myxomycetes, colloquially named slime moulds, are present in most terrestrial habitats. Molecular environmental sampling has revealed that a significant proportion of sequences could not be assigned to known species, with some specific groups showing a high hidden diversity. One such group included Stemonitis a...

While there is growing recognition of the importance of traditional knowledge in science, these perspectives remain underrepresented in research publications. However, the synthesis of these approaches has tremendous potential to improve our understanding of wildlife and ecosystems. Toward realizing this aim, we combined local traditional knowledge...

Several populations belonging to the genus Staurosirella have been observed in European rivers that were previously identified as Staurosirella pinnata. In light of the recent taxonomic revisions of the genus Staurosirella, the morphology of the unknown Staurosirella populations has been critically investigated using light and scanning electron mic...

During a survey of the diatom flora present on an artificial substratum (plexiglass) submerged off the southern Bulgarian Black Sea coast, a small-celled diatom taxon, reported previously from the Black Sea as Amphora (Halamphora) sp. S21, was observed. Detailed light and scanning electron microscope observations showed that the original taxon actu...

During a survey of diatoms present in tidal pools on the coasts of Livingston Island (South Shetland Islands), we found several populations, belonging presumably to the Antarctic endemic Craspedostauros laevissimus. Further analyses using light microscopy revealed that the populations show differences in stria density. Following scanning electron m...

Type specimens of four species of Lepidoderma (Myxomycetes, Amoebozoa)—L. crassipes, L. neoperforatum, L. perforatum, and L. stipitatum—have been studied using an integrative approach including application of traditional taxonomy methods, i.e., morphological study under stereoscopic and compound microscopes, detailed analysis of micromorphological...

During a survey of the marine benthic diatom flora on the coasts off Livingston Island (South Shetland Islands, Maritime Antarctic Region), two Halamphora species that could not be identified based on the currently available literature, were observed. Detailed light and scanning electron microscopy observations and thorough comparison with similar...

MORENO, J.F., G. MORENO, Á. LÓPEZ-VILLALBA & M. DE HAAN (2021). A new species of Didymium from Spain. Bol. Soc. Micol. Madrid 45: 13-19. A new species, Didymium charoae, is described from Spain, where it was collected growing on mosses that covered the bark of living trees of Quercus ilex ssp. ballota and, more rarely, on the bark itself. Macro-and...

Lowland tropical bryophytes have been perceived as excellent dispersers. In such groups, the inverse isolation hypothesis proposes that spatial genetic structure is erased beyond the limits of short‐distance dispersal. Here, we determine the influence of environmental variation and geographic barriers on the spatial genetic structure of a widely di...

Protecting aboveground carbon stocks in tropical forests is essential for mitigating global climate change and is assumed to simultaneously conserve biodiversity. Although the relationship between tree diversity and carbon stocks is generally positive, the relationship remains unclear for consumers or decomposers. We assessed this relationship for...

Five species of the terrestrial diatom genus Luticola D.G.Mann were found during a taxonomic survey of two small volcanic islands, Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean). Apart from the two already known Luticola species L. beyensii Van de Vijver et al. and L. subcrozetensis Van de Vijver et al., two new species are described: L....

In this poster we present a selected number of pages from the planned final publication on the Myxomycetes recorded in tropical Africa, the region between the Tropics of Cancer and Capricorn in the series Fungus Flora of Tropical Africa of the Botanic Garden Meise.

This poster presents the results of five surveys spanning a period of three years (2010-2013). A total of 261 specimens have been collected, these represent 27 genera, 69 species and 7 infraspecific taxa.

During a routine biomonitoring project of the water quality in rivers and brooks in Flanders, Belgium, an unusual Ulnaria taxon was found that could not be identified using the currently available literature. Based on detailed light and scanning electron microscopy observations, the unknown taxon is described as new to science: Ulnaria verhaegenian...

The digitization of herbaria and their online access will greatly facilitate access to plant collections around the world. This will improve the efficiency of taxonomy and help reduce inequalities between scientists. The Botanic Garden Meise, Belgium, is currently digitizing 1.2 million specimens including label data. In this paper we describe the...

Gathered needs per type of researcher

Eunotia rudis sp. nov. is described from material collected in acid rivers in an almost pristine tropical rain forest in the Congo Basin in Central Africa. The benthic diatom community was dominated by other Eunotia spp. and small naviculoid taxa. The morphological features of the new species are described and documented based on light and scanning...

Background and aims: The settling velocity of diaspores is a key parameter for the measurement of dispersal ability in wind-dispersed plants and one of the most relevant parameters in explicit dispersal models, but remains largely undocumented in bryophytes. The settling velocities of moss spores were measured and it was determined whether settlin...

A total of 137 observations of myxomycetes growing on epiphytic mosses were made in 17 localities in Flanders (Belgium). One of the objectives of this study was to determine which myxomycetes from these localities occur on and around this particular substrate. The importance of epiphytic mosses, as a substrate for the development of myxomycetes, is...

Gough Island (40°21’ S, 9°53’ W), part of the Tristan da Cunha archipelago, is a small, uninhabited island, situated in the cool-temperate zone of the southern Atlantic Ocean. Large parts of the island are quite mountainous with most of the island above 400 m. This volcanic island is typically oceanic and has never been part of a continental landma...

Conference poster

Conference Poster

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Background and aims – The past few years, the limnoterrestrial and aquatic diatom flora of the entire Antarctic Region (sub-Antarctic islands, Maritime Antarctic Region, Antarctic Continent) is currently under revision. One of the genera that still needed a revision is the genus Eunotia, quite common in wet to semi-wet moss vegetations in the sub-A...

Gyrosigma tenuissimum (W.Sm.) J.W.Griffith & Henfr. was examined in the original material and an emended description is presented. Its protologue contains an error of taxonomic significance: in the type material, the valve and raphe sternum do not show the considerable flexure described and illustrated in Smith (1853). A comparison with Gyrosigma c...

The presentation of three distinct Neidium taxa from the sub-Antarctic and Maritime Antarctic region after examining more than 1500 samples from a broad variety of aquatic and terrestrial (micro-)habitats suggests that taxa representing the genus Neidium Pfitzer are not only quite rare in these regions, but that the three species also represent wel...

Cavinula lilandae, a small new diatom from the Congo Basin in Central Africa, was observed in acid riverine habitats in an almost pristine tropical rain forest. It occurred in a periphytic diatom community dominated by Eunotia spp. and Fragilariforma strangulata (Zanon) Williams & Round. Beside the type locality in the Baomba Stream, and the closel...

The ultrastructure of Gomphonema gautieri (Van Heurck) Lange-Bert, et Metzeltin was studied based on a small population from a small Swedish, slightly acid, eutrophic river. The observations were compared with the holotype slide of G. augur var. gautieri Van Heurck, as the species was originally described in 1885. The valves are characterized in ha...

A revision of taxa from the genus Surirella from the Antarctic region resulted in the description of three new taxa: S. subantarctica Van de Vijver & Cocquyt sp. nov., S. heardensis Van de Vijver & Cocquyt sp. nov. and S. australovisurgis Van de Vijver, Cocquyt, Zidarova & Kopalová sp. nov. Detailed light (LM) and scanning electron microscope (SEM)...

Nitzschia epiphytica and N. epiphyticoides are two small diatoms from Central and East Africa described by Muller in 1905 and by Hustedt in 1949, respectively. To reduce the confusion that exists between the two species, the type of N. epiphyticoides and the original material of N epiphytica were reexamined by light and scanning electron microscopy...

During a morphological and taxonomical survey of the diatom flora of Swedish rivers, five new species have been observed: Caloneis langebertalotii Van de Vijver, Ector & Jarlman sp. nov., C. minuscula Van de Vijver, Ector & Jarlman sp. nov., Fragilaria sandellii Van de Vijver & Jarlman sp. nov., Geissleria scaniae Van de Vijver, Ector & Jarlman sp....

The monospecific diatom genus Cavernosa is known from only two locations: Kapiti Island off the west coast of New Zealand and Ile de la Possession, Crozet Archipelago, in the southern Indian Ocean. Cavernosa kapitiana Stidolph is a chain-forming diatom with cylindrical frustules having an elongated valve mantle. We provide a description of the diff...

In 2009 a study was started to culture aerial litter from selected plants in the park area and old-growth woodlands of the National Botanic Garden of Belgium. This resulted in the first records of Protosteloid amoebae (Amoebozoa) for Belgium. The samples were cultured following the method described by Olive and modified by Spiegel et al. Up to now...

As part of a study on the diatom flora of the Gokyo Valley, Everest National Park, Nepal, eleven species of Cymbopleura (Bacillariophyta), including two new species, Cymbopleura gokyoensis Jüttner et Van de Vijver sp. nov. and Cymbopleura emoda Jüttner et Van de Vijver sp. nov., were investigated using light and electron microscopy. Some taxa could...

During a survey of the non-marine diatom flora from lakes on James Ross Island (Maritime Antarctic Region), five new Luticola species have been recorded: Luticola desmetii, L. doliiformis, L. evkae, L. permuticopsis and L. tomsui. Detailed morphology descriptions of these taxa are given based on both light (LM) and scanning electron microscopy (SEM...

A revision of the diatom genus Navicula s.s. in inland water samples from the Sub-Antarctic and Antarctic resulted in the description of five new species, viz. Navicula australoshetlandica Van de Vijver sp. nov., N. dobrinatemniskovae Zidarova & Van de Vijver sp. nov., N. cremeri Van de Vijver & Zidarova sp. nov. N. conveyi Van de Vijver sp. nov. a...

In 1855, Smith described Achnanthidium lineare based on material collected in 1854 from Lasswade in Scotland. In his collection, a second entry for Achnanthidium lineare from 1854 is present, but based on material from the Vaucluse in southern France. Scanning electron microscopy analysis of both samples revealed that the Achnanthidium valves found...

Four new Achnanthidium species belonging to the species complex around A. minutissimum (Kütz.) Czarn. are described from different localities in Europe. Achnanthidium hoffmannii Van de Vijver, Ector, A. Mertens et Jarlman nov. spec. was found in several oligotrophic, circumneutral rivers in Sweden. The species is characterized by the presence of ir...

During a revision of the genus Luticola on the South Shetland Islands and James Ross Island, four unknown Luticola species were observed. Based on detailed light microscopy and scanning electron microscopy observations, the species are described as new to science: Luticola katkae Van de Vijver & Zidarova sp. nov., Luticola vermeulenii Van de Vijver...

In 2009 an ongoing study was started to culture aerial litter (dead but still attached plant parts) from selected plants in the park area and old-growth woodlands of the National Botanic Garden of Belgium (Meise, Province of Brabant). This resulted in the first records of Protostelids or protosteloid slime moulds from Belgium which are discussed in...

The genus Microcostatus was erected in 1998 by Johansen & Sray to accommodate a small number of tiny naviculoid species belonging to the former section Naviculae minusculae, characterized by the presence of the typical microcostae, a series of external transapical costae near the axial area, the possession of a simple raphe system and the lack of a...

Background and aims - The non-marine diatom flora of Livingston Island (South Shetland Islands, Maritime Antarctic Region) is currently under revision. One of the genera that still needed a revision is the genus Hantzschia, quite common in terrestrial habitats of the Antarctic Region.Methods - Using both Light Microscopical and Scanning Electron Mi...

Three new species and one new variety of the genus Cymbella are described from the Gokyo and Dudh Koshi Valleys in Everest National Park, Nepal. Cymbella himalaspera Jüttner & Van de Vijver and C. subhimalaspera Jüttner & Van de Vijver are related to species in the group around C. aspera (Ehrenberg) H. Peragallo but differ from similar taxa with re...

About thirty Belgian collections (BR, GENT, private herbaria) were assembled for this study. The revision results in the recognition of four species in the Belgian flora: Oligonema flavidum (the commonest species), 0. schweinitzii, 0. fulvum and 0. Intermedium (rare).Belgian material of the latter species was previously confused with 0. aurantium,...

Callus cultures of Ajuga reptans flowers produced a complex mixture of cyanidin- and delphinidin-based pigments, of which more than 90% were acylated. The anthocyanin composition varied little during one growth period. During a time span of 5 years no new anthocyanin classes appeared. Quantitative differences in anthocyanin composition between the...