<i>ELLERBECKIA BAILEYI</i>(H. L. SMITH) CRAWFORD &amp; SIMS COMB. NOV.: TYPIFICATION AND FRUSTULE MORPHOLOGY OF A RARE FRESHWATER FOSSIL DIATOM

Crawford, Richard M.; Sims, Pat

doi:10.1080/0269249x.2007.9705692

Cited by 6 publications

(5 citation statements)

References 4 publications

(2 reference statements)

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“…guyana is thus far unprecedented among diatoms. The imperfect rimoportulae height and position relative to the valve mantle margin were somewhat similar to the porelliportulae of some extant Ellerbeckia species [ 65 , 66 ] and extinct Truania [ 67 ]. The position of rimoportulae on post auxospore valves may reflect their ancestral position in the Paralia- lineage before they became located in their current position, by the Upper Cretaceous.…”

Section: Discussionmentioning

confidence: 56%

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Auxosporulation in Paralia guyana MacGillivary (Bacillariophyta) and Possible New Insights into the Habit of the Earliest Diatoms

Kaczmarska

Ehrman

2015

PLoS ONE

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BackgroundDiatoms are one of the most ecologically important aquatic micro-eukaryotes. As a group unambiguously recognized as diatoms, they seem to have appeared relatively recently with a limited record of putative remains from oldest sediments. In contrast, molecular clock estimates for the earliest possible emergence of diatoms suggest a considerably older date. Depending on the analysis, Paralia and Leptocylindrus have been recovered within the basal molecular divergences of diatoms. Thus these genera may be in the position to inform on characters that the earliest diatoms possessed.FindingsHere we present auxospore development and structure of initial and post-auxospore cells in a representative of the ancient non-polar centric genus Paralia. Their initial frustules showed unusual, but not unprecedented, spore-like morphology. Similarly, initial frustules of Leptocylindrus have been long considered resting spores and a unique peculiarity of this genus. However, even though spore-like in appearance, initial cells of Paralia readily resumed mitotic divisions. In addition, Paralia post-auxospore cells underwent several rounds of mitoses in a multi-step process of building a typical, “perfect” vegetative valve. This degree of heteromorphy immediately post-auxosporulation is thus far unknown among the diatoms.ImplicationsA spore-related origin of diatoms has already been considered, most recently in the form of the “multiplate diploid cyst” hypothesis. Our discovery that the initial cells in some of the most ancient diatom lineages are structurally spore-like is consistent with that hypothesis because the earliest diatoms may be expected to look somewhat similar to their ancestors. We speculate that because the earliest diatoms may have appeared less diatom-like and more spore-like, they could have gone unrecognized as such in the Triassic/Jurassic sediments. If correct, diatoms may indeed be much older than the fossil record indicates, and possibly more in line with some molecular clock predictions.

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Section: Discussionmentioning

confidence: 56%

“…Even though typical vegetative valves of Paralia and Ellerbeckia are somewhat similar (discussed in [ 65 , 70 ] and not repeated here; but see [ 66 ]); their initial cell valves are not. In fact, some characters seen in initial valves of P .…”

Section: Discussionmentioning

confidence: 99%

Auxosporulation in Paralia guyana MacGillivary (Bacillariophyta) and Possible New Insights into the Habit of the Earliest Diatoms

Kaczmarska

Ehrman

2015

PLoS ONE

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“…The study of Crawford and Sims [ 37 ] shows the species from the genus of Ellerbeckia are different from the species from the genus of Melosira. Although the species from the genus of Ellerbeckia are still under the name of genus of Melosira in the Algaebase database [ 38 , 39 , 40 ], the morphological features derived from Figure 1 , Figure 2 and Figure 3 specifically show that Ellerbeckia is a different genus than Melosira .…”

Section: Resultsmentioning

confidence: 99%

“…Although there are different morphologies, the images of both the Ellerbeckia and Melosira frustules show typical heavily silicified frustules with thick frustule walls. Moreover, both genera form a cylindrical shape with the valve faces linking together to form chains ( Figure 1 e,f, Figure 3 c, Figures S1a and S5a ) [ 37 , 38 , 39 , 40 , 41 ]. Tube processes are present in the mantle wall of these frustules.…”

Section: Resultsmentioning

confidence: 99%

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Gluch

Liao

et al. 2021

Nanomaterials

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Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms that Ellerbeckia is different from Melosira. Both genera reveal heavily silicified frustules with valve faces linking together and forming cylindrical chains. For this cylindrical architecture of both genera, valve face thickness, mantle wall thickness and copulae thickness change with the cylindrical diameter. Furthermore, EDS reveals that these fossil frustules contain Si and O only, with no other elements in the percentage concentration range. Nanopores with a diameter of approximately 15 nm were detected inside the biosilica of both genera using TEM. In situ micromechanical experiments with uniaxial loading were carried out within the nano-XCT on these fossil frustules to determine the maximal loading force under compression and to describe the fracture behavior. The fracture force of both genera is correlated to the dimension of the fossil frustules. The results from in situ mechanical tests show that the crack initiation starts either at very thin features or at linking structures of the frustules.

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“…Most species currently considered to belong to this species were formerly placed in either Melosira (sensu lato) or Paralia (Crawford, 1988;Crawford and Sims, 2007). The most common species is E. arenaria (Moore ex Ralfs) Crawford, which is commonly found on sandy sediments in large, oligotrophic to mesotrophic, North Temperate to Boreal lakes.…”

Section: Generamentioning

confidence: 99%

Centric and Araphid Diatoms

Kociolek

Theriot

Williams

et al. 2015

Freshwater Algae of North America

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ELLERBECKIA BAILEYI(H. L. SMITH) CRAWFORD & SIMS COMB. NOV.: TYPIFICATION AND FRUSTULE MORPHOLOGY OF A RARE FRESHWATER FOSSIL DIATOM

Cited by 6 publications

References 4 publications

Auxosporulation in Paralia guyana MacGillivary (Bacillariophyta) and Possible New Insights into the Habit of the Earliest Diatoms

Auxosporulation in Paralia guyana MacGillivary (Bacillariophyta) and Possible New Insights into the Habit of the Earliest Diatoms

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Centric and Araphid Diatoms

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