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Small star shaped fossil


The QCC

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Is this  an Echinoid?
CoralPyritized-Z2x.8_T.jpg.058aea8165809e9c399d1950e89f6f2b.jpg

 

I found this on the end of a piece of pyritized coral I received from Bob O'Donnell.

It looks like the teacher gave the coral a gold star for brilliance.
It is approximately 1mm across it's points.

Microscope: Zeiss Stemi 305edu, 2x photo eyepiece. Camera: Canon 1000d:

1x objective (2x mag.)

CoralPyritized-Z2x.8.thumb.jpg.edbdcee12c1428e53c71128dadef0e23.jpg

 

2x objective (4x mag.)

CoralStar-Z2x2.thumb.jpg.b6968c798bb96925f778bb0a73c0dba4.jpg

 

6x objective (12x mag.)

CoralStar-Z2x2x3_3922.thumb.jpg.0c88f274904e0d1b6a4fbb88d02c700c.jpg

 

 

 

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It's a nice looking crinoid columnal. 

Any idea of the age?

 

 

    Tim    -  VETERAN SHALE SPLITTER

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Sorry I'm no help, but it is an exquisite little thing with a lovely setting. I love the color contrast. :)

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I apologize for my lack of knowledge about the stem.
I received it from Bob O'Donnel who is the curator of the Arkona Lions Museum. He was showing me so many small fossils I was overwhelmed with names.
I recall he said it was pyritized and would look good under a microscope. The stem is approximately 27mm long and I did not see the star on the end until I rotated the stem under the microscope.
 

I picked up several chunks of matrix from the Hungry Hollow  Arkona formation, but do not believe the crinoid is from there.

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At this scale wouldn't the mathematical odds greatly favor it being a pinnule ?

Or does the shape preclude that alternative ?

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Looks like a crinoid stem section

“...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin

Happy hunting,

Mason

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2 hours ago, The QCC said:

It is approximately 1mm across it's points.

Ahem :)

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Good call, Dale. ;) 

 

 

image008.jpg

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    Tim    -  VETERAN SHALE SPLITTER

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__________________________________________________
"In every walk with nature one receives far more than he seeks."

John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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1 hour ago, ynot said:

Agree with crinoid colum segment.

The surface incrustation appears to be iron pyrite.

 

18 minutes ago, WhodamanHD said:

Looks like a crinoid stem section

If these refer to the larger piece I almost missed the fact that that might not be clear.

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The star shaped fossil is a nice crinoid columnal (pinnules are not pentagonal in cross section, as far as I know).

 

On the opposite side (picture #2 of O.P.) are encrusting epibionts, which look similar to Ascodictyon sp.

Here is an example of Ascodictyon vinelliforme (Kiepura, 1965) on Pentagonostipes petaloides (Moore and Jeffords, 1968), GIUS−4−2445/21, Figure F:

 

59309b6bd1119_Fig.3.thumb.jpg.e7d1bb0887e94b83735f867e91dd8e39.jpg

 

Also, here is an example of Pentagonostipes columnal articular facet (D & E, Fig. 3), which looks similar to the specimen in question:

v5n2a04.thumb.jpg.a5e02e1245d03270681754410dcb2f83.jpg

 

Reference:

Głuchowski, E. 2005. Epibionts on upper Eifelian crinoid columnals from the Holy Cross Mountains, Poland. Acta Palaeontologica Polonica 50 (2): 315–328

Scheffler, S. M. et al. 2010. Crinóides da borda leste da bacia do Parnaíba (Formação Cabeças, Devoniano Médio). Bol. Mus. Para. Emílio Goeldi. Cienc. Nat., Belém, v. 5, n. 2, p. 165-173

 

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We might want to point out that there is a taxonomic distinction between echinoids  and echinoderms too.

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That is correct. Echinoids and crinoids are echinoderms. :)

" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

My Library

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