Perhaps Stomisphaera, like Stomiosphaera echinata Nowak

Hello, 

your photos #3, 4 and 6 appear to have a 2-valve overlapping morphology similar to Schizosphaerella punctulata (see google image search screenshot attached):

oh, also check out Prinsiosphaera from Triassic ODP cores:

http://www-odp.tamu.edu/publications/122_SR/VOLUME/CHAPTERS/sr122_25.pdf

Thank you very much for the suggestions :)

Monika, in the 4th photo, the matrix of the limestone thin-section looks to me like it has an algal component to it as I see what I believe are algal cell structures covering the entire surface.  The calcisphere, I believe, is of algal origin as you can see the cells within the calcisphere itself.  If you have Adobe Photoshop Elements you can see the cell structure a little better by going to the tools section and clicking on Filter, Adjustments and Invert.  The calcisphere appears to be composed of an outer layer of more densely compact cells while the inner part of the sphere appears to be composed of more loosely packed cells.  You might try and make an organic matter strew slide of the rock material (a Palynology preparation without the oxidizing agent) and take a look at the organic matter content and type.  If this is algae there should be plenty of organic debris to look at.  I am not sure this will help but it's about all I can offer without seeing a Visual Kerogen (Organic Matter)  Slide.

Monika, I will try to attach a picture.  I am new to this site so I may not be doing things just right.  You may have to enlarge this photo on your screen but look closely at the center of the calcisphere and then the white-?algal network surrounding the sphere itself.  Hope I am not leading anyone down the wrong path here, but it does look to me like it is of algal origin.  I can't be absolutely sure that my interpretation is correct.

Thank you :) I will check the suggested possibilities.

Dear Monika,

Currently, the oldest calcareous dinoflagellate cysts known originate from Upper Triassic rocks but the affinities of the earliest fossils to extant calcareous dinoflagellates are doubtful for two reasons: they do not show dinoflagellate characteristics, such as an archeopyle and paratabulation, and there is a gap of around 50 mya between the isolated Triassic forms and the uninterrupted fossil record of undoubted Thoracosphaeraceae starting in the Late Middle Jurassic. During the Jurassic and Lower Cretaceous, cysts were produced world-wide and they are widely recognized from shelf and basin environments. Unfortunately literature for the Triassic calcareous dinoflagellate cysts is very few, I hope for you can be useful article of Janofske

(Janofske, D., 1992. Kalkiges Nannoplankton, insbesondere kalkige Dinoflagellaten-Zysten der alpinen Ober-Trias: Taxonomie, Biostratigraphie und Bedeutung für die Phylogenie der Peridiniales. Berliner Geowisenschaftliche Abhandlungen E 4).

I wish you success!

Daria

Thank you very much for this comment.

I am glad Daria pointed out the history of calc. dinocysts, because Schizosphaerella and Prinsiophaera are calcispheres which could possibly be calc. dino cysts, but they do not have the definitive characteristics to be certain.

Dear Monika,

Because your question was formulated: “Middle Triassic calcispheres?” I answered in this connection. On closer examination of attached photos, I turned my attention to the pictures 4 and 7. They resemble the sections of the species Gemeridella minuta Borza & Misik. I hope that for you in this case could be useful following articles:

1. Borza, K., Misik, M. 1975. Gemeridella minuta n. gen., n. sp. aus der oberen Trias der Westkarpaten. Geol. Zb., 26; 77-81.

2. Misik, M., Borza, K., 1978. Gemeridella, Didemnoides, Didemnum und Korperchen ahnlicher Gestalt aus dem Mesozoikum der Westkarpaten. Geol. Zb.– Geologica Carpathica, 29; 307–326.

Good luck!

Daria

Dear Monika,

theses records, if all calcispheres or in some cases ?foraminifers? are vey interesting to the wuestion related to the themes I worked on - indirect proof of "seaplants" as food source fpr placodonts: see e.g. attached paper.

I would be happy to get some reprint, if the paper will be published.

Greetings,

Cajus

Article Fossil Middle Triassic 'sea cows'-placodont reptiles as macr...

Dear Cajus,

I have found the calcispheres (?) by chance while working on the other subject. Calcispheres, algae, are completely new field to me, and I'm trying to find information what the objects really are. I wonder if they are cross-sections of calcareous forams (e.g., Nodosaria or Dentalina) - it is possible.  I have to check microstructure of walls of the objects - it can bring some explanations.

To my knowledge, only some Dasyclades (see the link below - Fig. 5) and single Globochaete alpina (found by me; cf. the second link below) are know from the Anisian, but its younger substages, i.e., Bithynian - Pelsonian, of Upper Silesia (S Poland).

http://paleopolis.rediris.es/cg/CG2013_B02/droite.htm

https://geojournals.pgi.gov.pl/agp/article/view/9894/8427

The object presented here are slightly older (Aegean, maybe Bithynian).

I have already read your interesting papers :)

Hi Monika,

I worked long time ago fewe (some cross sections carbonate facies) with Cenomanian calcispheres (which were thought to originate from "seagrass") - so I am not at stage of knowledge, but this should appear not before Late Cretaceous - but I am "outdated" in this theme. Forams are well known in the Germanic Basin Triassic - especially benthic ones.

Greetings,

Cajus

Thank you for this suggestion :)

Globocheta can be identified easily with polarized light, they have a very peculiar extinction in cross, turning when you turn the microscope plate. Globocheta sometimes occurs in chains. I would rather say that your form are microproblematica (Nagy 1966 or Borza 196 etc...) or they may be foraminifera in section.

Silvia

I call them Stomiosphaera sphaerica (It also exists in the Cretaceous carbonates in Libya), I can say, it is not nodosariids foraminifers, as no way to find with them any single longitudinal sections shows the uniserial arrangement, even in the cretaceous sediments of Libya. It is more likely Stomiosphaera sphaerica rather than Pithonella ovalis from the spherical shape.

This is only my opinion I am not calcispehere specialist, but from my few experience with Libyan stratigraphy.

Calcispheres are possible, as are micro-foraminifera. If they were dentaline or nodosarid foraminifera I would expect to see at ,East an oblique section with more than one chamber. In response to comment above, calcispheres are probably related to dinoflagellates as some have tabulation inside. They are not related to sea grass, the earliest of which is latest Campanian.

Thank you very much for this comment.