Flatonia Texas Eocene Diatomite thread

[miha]

I made today an Arrangement from the K7 sample.

[bill2penn]

Dear Michel,
FANTASTIC!!

There are several of these forms that I have not observed yet.

Best regards,
Bill

[Beatsy]

I made today an Arrangement from the K7 sample.

Beautiful arrangement with great variety.

Amazing you got that pennate form 3rd from the right on the 2nd row to stay balanced on it's face too. It's so skinny. I had to swear a lot before I eventually got one to "stand up" properly 

Cheers
Beats

[anne]

Dear Michel,
I think your day must have 48 hours...
Absolutely wonderful and the best overview up to now.
best
anne

[bernd552]

Hallo zusammen,


Nach dem ich nun die grossen Diatomeen herausgefiltert habe, bleibt jede Menge feinster Sand mit den kleinsten Diatomeen übrig. Mit dekantieren komme ich so nicht weiter. Ein feineres Sieb als 25µ habe ich nicht. Ich habe überlegt wie ich nun den Sand von den kleinen Diatomeen trennen kann.
Ich bin dabei auf die Goldwäscher Methode gekommen. Dazu habe ich das feine Material mit Wasser in ein
Uhrenglas gegeben und kreisförmig geschwenkt. Dabei sammeln sich grössere Sandkörner in der Mitte.
Diese Ansammlung habe ich heraus pipettiert und verworfen. Das verbleibende Material im Uhrenglas habe
ich wiederum geschwenkt. Das sich sammelnde Material, bestehend aus feinen Sand und kleinen Diatomeen habe ich heraus pipettiert und in einem kleinen Glässchen gesammelt. Dies habe ich eine weile stehen
lassen.
Von dem Bodensatz habe ich etwas aufgenommen und auf ein OT gegeben. Es war feiner Sand und kleine Diatomeen zu sehen. diesen OT habe ich leicht im Kreis geschwenkt. Da der Sand kleiner als die kleinen Diatomeen sind, sammeln sich diesmal fast nur Diatomeen ohne den störenden feinsten Sand in der Mitte
des Tropfens. Diese Ansammlung, habe ich herauspipettiert und gesammelt. 
Diesen Vorgang habe ich solange wiederholt bis der Bodensatz aus dem ersten Gefäss entfernt ist.
Verklumpungen von Diatomeen, meist an Fasern, habe ich durch 25µ Filterung entfernt.
Nun sind die kleinen Diatomeen so gut wie sandfrei.  Es ich eine recht mühselige Methode, die aber
funktioniert. Ich habe mal ein Schaubild bei gefügt.

LG
Michael

Lieber Michael,

die fraktionierte Sedimentation leistet nach meiner Erfahrung auch gute Dienste

https://www.mikroskopie-forum.de/index.php?topic=41337

LG
Bernd

[Michael K.]

Hello Michel,


That is a very nice Arrangement!  I have never seen the round Form (5th row, 4th on the right).
It looks very bizarre.


Greeting
Michael

[miha]

Dear Michel,
FANTASTIC!!

There are several of these forms that I have not observed yet.

Best regards,
Bill

Hi Bill,

Thanks, Fantastic to find some species I never seen before.
Let`s hope that you all find this species too.

B R,
Michel

[miha]

I made today an Arrangement from the K7 sample.

Beautiful arrangement with great variety.

Amazing you got that pennate form 3rd from the right on the 2nd row to stay balanced on it's face too. It's so skinny. I had to swear a lot before I eventually got one to "stand up" properly 

Cheers
Beats

Hi Beats,

Thanks
I have try to use a micromanipulator but I can`t work with.
With the manipulator the diatoms jump on top of the needle and can`t get it off the needle.
I still use a cathair on a wooden stick and that works much better for me.
With this method, you do have to skip the drink.

B R,
Michel

[miha]

Hello Michel,


That is a very nice Arrangement!  I have never seen the round Form (5th row, 4th on the right).
It looks very bizarre.


Greeting
Michael

Hello Michael,

Thanks, it`s a fantastic sample that gives some fantastic not described species.
It will give us a lot of fun the upcomming time.

B R,
Michel

[Carsten Wieczorrek]

Hello,
I asked our Michael K. if he could provide me with his images of algae #49, #51, and #52 in a format that my AI experiment can read. He said yes and suggested I post the results here.
Enjoy reading,
Carsten

Michael K. Image #49
Identification: Unclear / Probable Sponge Spicule (Amphidisc)
(Size: 90 µm)

1. Structure analysis:
• Symmetry: Bipolar and axially symmetric (dumbbell-shaped). It does not exhibit the classic centric (radial) or pennate symmetry of a standard diatom valve.
• Rib structures & Center: The object consists of a solid, hyaline (transparent), slightly bent central shaft. There are absolutely no visible transverse ribs (striae), no central nodule, and no raphe or pseudoraphe system.
• Areolae pattern: Completely absent. The two expanded, bell-shaped (umbellate) ends show concentric ridges or growth lines, but completely lack any hexagonal areolae network, porous structures, or sieve plates typical for siliceous algae.

2. Best matching algae:
1. Chaetoceros (as an atypical resting spore) – < 10 %
(Note: As per the rules, since the maximum probability for an algae is < 30%, only the single most likely genus is listed).

3. Conclusion:
Based strictly on the visible anatomical features (meristics), this object lacks all fundamental diagnostic characteristics of a diatom frustule. The probability of it being a diatom is well below 30%. While finding undescribed species at new locations is possible, morphologically and given the specific length of 90 µm, this structure perfectly matches a siliceous sponge spicule (specifically an "amphidisc" or "birotulate" from the phylum Porifera). These spicules survive the acid preparation process and are extremely common by-catch in diatom samples. If forced into an algae category, it could only be interpreted as a highly deformed resting spore, but a non-algal origin is the only anatomically logical conclusion here.


Michael K. Image #51
Identification: Neidium iridis
(Size: 170 µm)

1. Structure analysis:
• Symmetry: Pennate (bilaterally symmetric) and isopolar. The valve exhibits a classic elliptical-lanceolate outline with slightly wedge-shaped (cuneate) to bluntly rounded apices.
• Rib structures & Center: A straight, central raphe system is clearly visible. The central nodule/area is relatively small. The most critical diagnostic features are the prominent, straight longitudinal lines (canals or blank bands) running parallel to the valve margins on both sides of the raphe.
• Areolae pattern: The transverse striae are arranged parallel to slightly radiate near the center. Unlike the solid, smooth costae seen in genera like Pinnularia, these striae are finely punctate (porous). These punctate striae are characteristically crossed and interrupted by the longitudinal marginal canals.

2. Best matching taxa:
1.Neidium iridis – 85 % (The combination of distinct longitudinal bands, punctate striae, lanceolate shape, and especially the impressive length of 170 µm are perfect morphological matches for this large species or its direct complex).

2.Neidium amphigomphus – 10 % (Shares the genus-specific longitudinal canals and large size, but typically features much broader, more sharply wedge-shaped apices).

3.Caloneis permagna – 5 % (Can reach similar enormous sizes and has a comparable elliptical-lanceolate shape, but features a different type of marginal line and typically has smooth alveoli rather than distinctly punctate striae).

3. Conclusion:
Strictly based on visible anatomy, the prominent longitudinal bands running parallel to the margins that interrupt the finely punctate transverse striae unambiguously assign this alga to the genus Neidium. Factoring in the substantial length of 170 µm, which eliminates the vast majority of smaller pennate diatoms, Neidium iridis is the most accurate and logical morphological determination. Even if it is a potentially undescribed local variation, it morphologically falls right into the Neidium iridis complex.



Identification: Stictodiscus californicus
(Size: 110 µm)

1. Structure analysis:
• Symmetry: Centric (radial symmetry) with a strictly circular valve outline (discounting the mechanical damage at the upper right margin).
• Rib structures & Center: The valve features a broad, distinct central area that lacks a hyaline (transparent) ring or an organized rosette. Instead, the center is filled with large, clearly separated, and loosely arranged areolae. Radiating outwards from the boundary of this central zone to the outer margin are very prominent, thick radial ribs (costae).
• Areolae pattern: Between the strong radial costae, the areolae are arranged in regular, linear to slightly concentric rows. The areolae in the central field are noticeably larger and more irregularly scattered compared to the strictly ordered, finer pores in the outer radial sectors.

2. Best matching taxa:
1. Stictodiscus californicus – 85 % (The broad central area with scattered large pores combined with massive radial costae is the textbook anatomical blueprint for this species. The measured diameter of 110 µm fits perfectly into its typical size range, a classic morphology often found in Oamaru-type deposits).

2. Stictodiscus buryanus – 10 % (Shares the genus-specific radial ribs and porous center, but typically shows minor deviations in the exact spacing and proportion of the central field versus the radial zone).

3.Arachnoidiscus sp. – 5 % (Shares the prominent macroscopic radial ribs, but is anatomically excluded here because it lacks the definitive Arachnoidiscus features: a central hyaline ring and an inner rosette of elongated areolae).

3. Conclusion:
Based strictly on the visible meristics, the combination of massive radial ribs (costae) originating from a large, unorganized central field filled with coarse areolae clearly assigns this specimen to the genus Stictodiscus. Incorporating the arrangement of the pore rows and the precise diameter of 110 µm, Stictodiscus californicus is the most accurate and logical morphological determination. The mechanical damage at the upper right edge does not impede the structural analysis of the remaining intact valve.