Biodiversity at the Microbial Level: The Number of Free-Living Ciliates in the Biosphere

Finlay, Bland J.; Corliss, John O.; Esteban, Genoveva F.; Fenchel, Tom

doi:10.1086/419370

Cited by 146 publications

(86 citation statements)

References 37 publications

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“…This should not be surprising in view of the incomplete morphologic data; that is to say, the "morphospecies concept" has been applied despite an inadequate morphologic basis (Esteban et al 1995;Finlay et al 1996). One example of this is the unsupportable synonymy proposed between M. striatus and M. violaceus (Esteban et al 1995).…”

Section: Notice: This Ismentioning

confidence: 99%

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Morphologic and molecular description of Metopus fuscus Kahl from North America and new rDNA sequences from seven metopids (Armophorea, Metopidae)

Bourland

Wendell

Hampikian

2014

European Journal of Protistology

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Most species in the large ciliate genus Metopus Claparède & Lachmann, 1858 lack detailed descriptions based on modern morphologic and molecular methods. This lack of data for the vast majority of species hampers application of a morphospecies approach to the taxonomy of Metopus and other armophorids. In this report we redescribe the large species, Metopus fuscus Kahl, 1927 based on in vivo observation, silver impregnation, scanning electron microscopy, and single-cell 18S rDNA sequencing of a freshwater North American (Idaho) population. Metopus fuscus invariably has a perinuclear envelope of endosymbiotic bacteria not found in other species. Unlike the original description of a single row of coarse granules between ciliary rows, the Idaho population has five loose rows of small interkinetal granules. We discuss the possible importance of this character in metopids. We also provide a phylogenetic analysis including setosus form a fully supported clade, challenging previous morphospecies groupings. We discuss some ambiguities of armophorid morphologic terminology in the earlier literature. Our phylogenetic analysis of Idaho metopids indicates that the genera Metopus and Brachonella are both nonmonophyletic.

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Section: Notice: This Ismentioning

confidence: 99%

“…"morphospecies" concept as it has been applied to the free-living Armophorida (Esteban et al 1995;Finlay et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Morphologic and molecular description of Metopus fuscus Kahl from North America and new rDNA sequences from seven metopids (Armophorea, Metopidae)

Bourland

Wendell

Hampikian

2014

European Journal of Protistology

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“…In protistology, species descriptions often pragmatically conform to the morphological species concept: microbial eukaryotes have traditionally been identified on the basis of their morphological diversity (Finlay et al, 1996). In general, such a concept seems to work well for a number of larger protists.…”

Section: Introductionmentioning

confidence: 99%

Multigene phylogenies of clonal Spumella-like strains, a cryptic heterotrophic nanoflagellate, isolated from different geographical regions

Stoeck¹,

Jost²,

Boenigk³

2008

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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Many nanoflagellate morphospecies comprise an enormous variation of genotypes, probably indicating cryptic species. One of the best-investigated morphospecies with respect to molecular and ecophysiological variation are flagellates of the Spumella morphotype. Here, we have phylogenetically analysed three protein-coding genes (actin, alpha-tubulin, beta-tubulin), internal transcribed spacers (ITS1, ITS2) and the 5.8S rDNA of 17 Spumella-like strains isolated from soil, freshwater and marine samples in order to (i) test the validity of the current Spumella-like phylogenetic classification system based exclusively on small subunit (SSU) rDNA, (ii) elucidate the phylogenetic associations of SSU rDNA-unresolved strains and (iii) evaluate the validity of the assignment of ecophysiological adaptations to previously identified SSU rDNA sequence clades. All single-gene analyses show different patterns of support, are incongruent and identify a number of conflicting nodes. Likewise, a concatenation of all protein genes fails to recover specific SSU rDNA clades. However, a combined analysis of all genes confidently resolved the conflicts of the single genes and the protein-gene concatenations and resulted in a tree topology that is identical to the SSU rDNA analysis, but with enhanced phylogenetic resolution and decisively greater support. We conclude that, depending on the genes concatenated, a 'supergene' analysis minimizes artefactual effects of single genes and may be superior in its performance in phylogenetically analysing cryptic species. We confirm the validity of the SSU rDNA Spumella-like phyloclades and support the suggestion that these clades indeed seem to reflect certain ecophysiological adaptations. INTRODUCTIONIn protistology, species descriptions often pragmatically conform to the morphological species concept: microbial eukaryotes have traditionally been identified on the basis of their morphological diversity (Finlay et al., 1996). In general, such a concept seems to work well for a number of larger protists. However, numerous smaller species (nanoand picoeukaryotes) are morphologically indistinguishable (Coleman, 2002;Hackstein, 1997;Nanney, 2004), as evolution and speciation in microbial eukaryotes are not necessarily accompanied by a perceptible morphological change (Machelon et al., 1984). As a consequence, distinct microbial eukaryote species are often classified as a single species (5cryptic species). The prevalence of such cryptic species impairs biodiversity estimates and analyses of spatial distribution patterns and ecological functions (Bickford et al., 2006;Coleman, 2002;Hackstein, 1997).A group of organisms that falls into this category are colourless chrysophytes often referred to as 'Spumella-like' flagellates or Spumella spp. (Auer & Arndt, 2001;Cleven & Weisse, 2001;Weitere & Arndt, 2003). These organisms account for a substantial proportion of the heterotrophic nanoflagellate (HNF) biomass, especially in freshwater systems (Domaizon et al., 2003;Felip et al., 1999;Zhao et al., 2003), and...

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“…Estes picos adaptativos poderiam ser considerados como pequenas elevações dentro da paisagem dimensional criada por Wright, permitindo uma ampla variação morfológica, pois caso contrário, o valor adaptativo do genoma no alto de um pico elevado faria com que a pressão de seleção para as demais variantes fosse aumentando a probabilidade de serem eliminadas. Pelo exposto torna-se possível, a utilização do conceito de morfoespécies definido por FINLAY et al, (1996) e FINLAY, (1998).…”

Section: Conceito De Espécies Em Tecamebasunclassified

“…Consiste na produção de uma nova teca sem ocorrer a divisão nuclear, deste modo o organismo (a célula) migra para a nova teca abandonando a velha teca. Também há a ocorrência de formação de uma nova teca sem ocorrer a divisão nuclear e a migração do corpo celular, este fenômeno foi observado em aproximadamente 1% dos indivíduos, (HEGNER, 1919 1959;MEDIOLI & SCOTT, 1983FINLAY et al, 1996;CHARMAN, 1999;CRUZ, 2004;GOMES E SOUZA, 2008 VELHO et al, (1999VELHO et al, ( , 2003, LANSAC-TÔHA et al (2004), LEIPNITZ et al, (2006, ALVES et al, (2007ALVES et al, ( , 2012 DULEBA et al, 2004DULEBA et al, , 2005SEMENSATTO et al, 2004;ALVES et al, 2008;LEÃO et al, 2009;e LEIPNITZ et al, 2014) .…”

Section: Conceito De Espécies Em Tecamebasunclassified

Estudo multidisciplinar da evolução ambiental do Reservatório de Salto Grande, Americana, SP, a partir de análises multiproxies geoquímicos, de magnetismo ambiental e biológicos (Tecamebas)

Lerena¹,

María²

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Biodiversity at the Microbial Level: The Number of Free-Living Ciliates in the Biosphere

Cited by 146 publications

References 37 publications

Morphologic and molecular description of Metopus fuscus Kahl from North America and new rDNA sequences from seven metopids (Armophorea, Metopidae)

Morphologic and molecular description of Metopus fuscus Kahl from North America and new rDNA sequences from seven metopids (Armophorea, Metopidae)

Multigene phylogenies of clonal Spumella-like strains, a cryptic heterotrophic nanoflagellate, isolated from different geographical regions

Estudo multidisciplinar da evolução ambiental do Reservatório de Salto Grande, Americana, SP, a partir de análises multiproxies geoquímicos, de magnetismo ambiental e biológicos (Tecamebas)

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