Cretaceous Diatoms from Marca Shale collected in Panoche Hills, California

[bill2penn]

I now believe that this is a previously undescribed new species of Entogoniopsis. It is very similar to Entogoniopsis polycistinora but different. Stacked image taken with Leitz Pl Fluotar phaco 2 40X/0.70 under phase contrast. Total image width is 100 microns.

[Michael K.]

Hello Bill,

Where are the differences?


Greetings
Michael

[bill2penn]

Hello Michael,

Perhaps it is easiest to compare the two images. In 2015 board user Anatol posted this beautiful brightfield image of E. polycistinora
https://www.mikroskopie-forum.de/index.php?topic=23161.0

If you compare that image to my phase contrast image (which is really needed to see the large pores) you can see that E. polycistinora has two or three rows of pores in between each rib while my species has only one row or maybe two between each rib. Then right in the center of the form the E. polycisinora has a circular plate that the ribs attach to like spokes in a bicycle wheel. My species has just the ribs coming together. There is also a hyaline ridge around my form that is lacking in polycistinora but that can only be observed by REM.

(I apologize for not using the correct terminology for the pores and ribs. I will look them up)

Greetings,
Bill

[bill2penn]

Here is the first example I found of Sheshukovia pruninosum. Stacked image using Leitz Pl Fluotar Phaco2 40X/0.70 under brightfield conditions.
Bill

[anne]

Hi Bill,
wow, wonderful! It was in a Nodule?
best
anne

[bill2penn]

Hi Anne,
Yes, I think I found it in R-9 which you have a sample of.
Bill

[Rene]

Hi Bill, did you find these nodules on all sites, or concentrated in space or time?

Best, René

[bill2penn]

Hi Rene,
The nodules that have the well preserved diatoms seem to be located only in Dosados canyon at around the 35 meter mark. I attach an image of the hillside where we collected for about 100 meters near the top (the red lines on the image). The nodules were concentrated around the 35 meter mark (the left side of the hill) all the way down the hill.  I have examined other, identically looking nodules that were collected in other parts of the Marca shale but while they react similarly with dilute HCl, they don't seem to have any diatom or radiolarian forms.
Bill

[Michael K.]

Hello Bill,

Very nice Found. I have to look at the Marce samples again.


Greeting
Michael

[Rene]

Thanks Bill. Unfortunately, I'm a novice in geology matters. Do you have any ideas about how narrow the time window was for these nodules?

Best, René

[bill2penn]

Sorry Rene. I am also not a geologist. I think the entire 100 meter Marca shale layer took a couple million years to form.
Bill

[bill2penn]

Benetorus fantasmus. Stacked brightfield image using Leitz Pl Apo 40X/0.75. Width of form is 50 microns.
Bill

[Michael K.]

Hallo,

Momentan schaue ich mir die Dosados Probe (Knötchen) nochmal an. Evtl. ist ja noch die ein oder andere unbekannte Form dabei.  Auch wenn manche Formen schon zu sehen waren, füge ich eine weitere Ansicht bei.
Bin mir recht sicher, das es sich hierbei um die "Sheshukova excavata" handelt.
Aufgenommen mit dem 40er Obj. bei schräg gestellter trockener Diatomee.

LG
Michael

[bill2penn]

Very nice Michael!
Here is the only complete and unbroken Kittonia hannae that I have found so far. Stacked image taken with Leitz Pl Apo 40X/0.75. I don't know why the arms are so dark. Perhaps I didn't clean the form well enough.
Bill

[Rene]

Amazing. Congrats Bill, on a great expedition.

René