Historical and Current Perspectives on the Systematics of the ‘Enigmatic’ Diatom Genus Rhoicosphenia (Bacillariophyta), with Single and Multi-Molecular Marker and Morphological Analyses and Discussion on the Monophyly of ‘Monoraphid’ Diatoms

@article{Thomas2016HistoricalAC,
  title={Historical and Current Perspectives on the Systematics of the ‘Enigmatic’ Diatom Genus Rhoicosphenia (Bacillariophyta), with Single and Multi-Molecular Marker and Morphological Analyses and Discussion on the Monophyly of ‘Monoraphid’ Diatoms},
  author={Evan William Thomas and Joshua G Stepanek and John Patrick Kociolek},
  journal={PLoS ONE},
  year={2016},
  volume={11}
}
This study seeks to determine the phylogenetic position of the diatom genus Rhoicosphenia. Currently, four hypotheses based on the morphology of the siliceous valve and its various ultrastructural components, sexual reproduction, and chloroplasts have been proposed. Two previous morphological studies have tentatively placed Rhoicosphenia near members of the Achnanthidiaceae and Gomphonemataceae, and no molecular studies have been completed. The position of Rhoicosphenia as sister to ‘monoraphid… 

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References

SHOWING 1-10 OF 101 REFERENCES
Molecular data show the enigmatic cave-dwelling diatom Diprora (Bacillariophyceae) to be a raphid diatom
TLDR
A three-gene phylogeny, based on nuclear (SSU rDNA) and chloroplast (rbcL, psbC) genes, is presented to determine the phylogenetic relationships of Diprora in the diatom tree of life and shows this diatom to be most closely allied with taxa referred currently to the Sellaphoraceae, including Sellaphora or Fallacia.
Phylogenetic relationships and classification of monoraphid diatoms based on phenetic and cladistic methodologies
TLDR
P Phenetic and cladistic analyses of the character state data suggest that the major genera of the Achnanthaceae may form distinct evolutionary lineages, which have each converged on the reduced raphe condition.
A preliminary phylogenetic analysis of the Cymbellales based on 18S rDNA gene sequencing
TLDR
The results indicate that the Cymbellaceae Greville and Gomphonemataceae Kützing are paraphyletic, and that the significance of some of the morphological characteristics traditionally used for classification purposes requires a reassessment.
STRUCTURE, LIFE HISTORY AND SYSTEMATICS OF RHOICOSPHENIA (BACILLARIOPHYTA). I. THE VEGETATIVE CELL OF RH. CURVATA 1
TLDR
The structure and formation of the two types of valve are described, and the heterovalvy shown to be of a different type from that of the monoraphids; on the basis of raphe, valve and girdle structure a close relationship between these and Rhoicosphenia is unlikely.
MORPHOLOGICAL AND MOLECULAR INVESTIGATIONS OF NAVICULOID DIATOMS. II. SELECTED GENERA AND FAMILIES
TLDR
A molecular analysis of 91 species of naviculoid diatoms representing 22 genera and 72 species found support was found for many groups established by traditional morphological methods, although individual genera were monophyletic.
Molecular phylogeny of the Cymbellales (Bacillariophyceae, Heterokontophyta) with a comparison of models for accommodating rate variation across sites
TLDR
Assessing how different models for ASRV affect tree topology and clade support values seems important in cases of sparse or unbalanced taxon sampling or when assessing the phylogenetic affinity of previously unsampled taxa when lineage-specific biases in base composition or evolutionary rate are more difficult to detect.
Systematics of naviculoid diatoms (Bacillariophyta): A preliminary analysis of protoplast and frustule characters for family and order level classification
TLDR
The hypothesis that monoraphid genera have arisen independently from different naviculoid diatoms, and that Achnanthes sensu stricto should be transferred to the Mastogloiales is supported.
Ultrastructure of Cymbella sinuata and Its Allies (Bacillariophyceae), and Their Transfer to Reimeria, gen. nov.
TLDR
Observations show the C. sinuata group shares features of valve symmetry and number of apical pore fields with members of the genus Cymbella, while having raphe, striae, and stigmal features similar to Gomphonema species, and suggest its placement in a new genus, Reimeria.
Evolution of the diatoms: V. Morphological and cytological support for the major clades and a taxonomic revision
TLDR
Phylogenetic reconstructions of the diatoms have been inferred with the 18S and 16S ribosomal RNA genes, and two new subdivisions are proposed (Coscinodiscophytina and Bacillariophytine) and a new class, the Mediophyceae for the bipolar centrics and the Thalassiosirales is proposed.
...
...