Loricae and Cysts in the Chrysophyceae

Bourrelly, Pierre

doi:10.1111/j.1749-6632.1963.tb13396.x

Cited by 19 publications

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“…and Ochromonas spp. ; Bourrelly 1963). In fact, we found considerable differences between cysts produced by different strains of Spumella .…”

Section: Discussionmentioning

confidence: 99%

“…They attracted attention as a means for differentiating taxa with similar vegetative cell morphologies. For instance, cyst morphology is used for species identification in the genera Uroglena and Ochromonas (Bourrelly 1963). Further, the ecology of cyst-forming taxa became a focus of interest, as resting stages, specifically those of golden algae (chrysophytes or chrysomonads), are common indicators in past climate reconstruction (Smol and Cumming 2000, Catalan et al 2002, Betts-Piper et al 2004, Kamenik and Schmidt 2005.…”

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confidence: 99%

“…As the genus Spumella is an aggregate taxon (see Boenigk 2008b, Pfandl et al 2009) and recent studies have indicated that this morphodeme evolved at least three to five times independently (Boenigk et al 2005), we use the term Spumella-like flagellate to refer to all flagellates of this morphodeme. Their resting stages are hollow siliceous spheres with a tiny pore (Duff et al 1995), which is closed with a pectinous and sometimes siliceous plug (Bourrelly 1963, Hibberd 1977). Yet, only few studies have investigated the stomatocysts in Spumella (Cienkowsky 1870, Belcher and Swale 1976, Yubuki et al 2008, and thus their systematic value can currently hardly be judged.…”

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confidence: 99%

“…Their resting stages are hollow siliceous spheres with a tiny pore (Duff et al. 1995), which is closed with a pectinous and sometimes siliceous plug (Bourrelly 1963, Hibberd 1977). Yet, only few studies have investigated the stomatocysts in Spumella (Cienkowsky 1870, Belcher and Swale 1976, Yubuki et al.…”

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confidence: 99%

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Taxonomic and Ecological Characterization of Stomatocysts of Spumella-Like Flagellates (Chrysophyceae)1

Findenig

Chatzinotas

Boenigk

2010

Journal of Phycology

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Cyst formation is a characteristic feature of chrysophytes. Cyst morphology is used for species identification, and the distribution of cysts in sediment cores is used to infer past climate conditions. The affiliation of stomatocyst demes with morphospecies, however, remains unclear. Here, we investigated the taxonomic and ecological value of the occurrence of cyst formation and cyst morphology to differentiate chrysophyte flagellates of the Spumella-morphodeme, which are among the numerically dominant eukaryotes in many aquatic and terrestrial habitats. In the investigated 90 strains of Spumellalike flagellates, we observed encystment only in six strains despite the broad range of temperature regimes and chemical factors tested. Spumella-like flagellates that produce cysts are affiliated with different subclusters within the Chrysophyceae and are closely related to strains for which cyst formation is not known. The occurrence of cyst formation is therefore unsuitable as a taxonomic criterion. Cyst morphology allows for differentiating some strains even though distinctly different strains may have similar or even identical-looking cyst demes. Despite considerable changes in cell size of the vegetative cells related to the nutritional status, the size of the cysts was always larger than that of a typical vegetative cell. Cysts were colorless and had no chromatophores, and some granula were visible in the light microscope. None of the investigated strains and none of the so far published cyst descriptions of Spumella spp. entirely seem to match the cyst description of the generic type strain. However, taking methodological bias between light and electron microscopical investigations into account, the cysts 199hm (this paper) and N1846 (Yubuki et al. 2008 seem to correspond to the cyst of the generic type strain. We propose the strain 199hm as epitype for Spumella vulgaris Cienkowsky; we further describe Spumella rivalis Boenigk et Findenig sp. nov., Pedospumella encystans Boenigk et Findenig gen. et sp. nov., and Poteriospumella lacustris Boenigk et Findenig gen. et sp. nov.

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“…and Ochromonas spp. ; Bourrelly 1963). In fact, we found considerable differences between cysts produced by different strains of Spumella .…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Taxonomic and Ecological Characterization of Stomatocysts of Spumella-Like Flagellates (Chrysophyceae)1

Findenig

Chatzinotas

Boenigk

2010

Journal of Phycology

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Chrysophyceae and Synurophyceae

Jordan¹,

Iwataki²

2012

Encyclopedia of Life Sciences

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Until recently, the chrysophytes were an algal group with mixed affinities and variable morphologies, united largely by their golden brown pigmentation. However, morphological and genetic studies have progressively removed many of the unaffiliated taxa, leaving two closely related classes, the Chrysophyceae sensu stricto and the Synurophyceae. Both the classes contain freshwater and marine species, although are considered more abundant and diverse in oligotrophic waters in terrestrial habitats. Cells may be solitary or colonial, having unequal flagella (heterokont), with flagellar swellings on one or both flagella acting as photoreceptors. Taxa covered by siliceous scales are present in both classes, although silicified bristles are only present in some synurophytes. Some chrysophytes may form cellulosic, chitinous, siliceous or calcareous loricae instead of possessing scales. All taxa from both classes produce resting stages known as stomatocysts, with some species forming them during both asexual and sexual phases. Since stomatocysts, and to a lesser extent scales and bristles, are preserved in the underlying sediments, their fossil record is relatively well known, with the oldest stomatocysts found in Early Cretaceous sediments. Fossil stomatocysts have proven very useful in palaeolimnological studies, particularly when reconstructing past nutrient levels, whereas their marine counterparts are a proxy for past sea‐ice distribution. Key Concepts: Genetic studies have shown that the Chrysophyceae sensu stricto and Synurophyceae are closely related, whereas the other taxa previously included in the Chrysophyceae sensu lato belong to different algal classes. Chrysophytes and synurophytes are heterokont algae, with a long ‘flimmer’ flagellum and a short ‘whiplash’ flagellum and with flagellar swellings on one or both flagella. Fucoxanthin is the main pigment responsible for their ‘golden brown’ colouration. Cells may possess silicified scales (but only synurophytes have bristles) produced by Golgi‐derived vesicles. Scale and bristle morphology appears to be species‐specific and is thus a key criterion in the identification of the taxa. Silicified resting stages bearing a plugged pore (stomatocysts) are unique to the Chrysophyceae and Synurophyceae, and may also be species‐specific. Stomatocysts are often preserved in the underlying sediments, and have been used as palaeoenvironmental indicators. The oldest stomatocysts were found in Early Cretaceous marine sediments from the Southern Ocean, whereas the oldest silicified scales and bristles were found in Middle Eocene freshwater sediments from northwest Canada.

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