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Wrens Nest Graptolite?


Tom Hughes

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Dear all,

I recently went for a trip to Wrens Nest and found this small, what I believe Dendroid Graptolite. It measures ~2cm (apologies for the poor quality of the image).

 

If anyone could suggest a Sp. ID, or even if it is a Graptolite that would be very much appreciated. 

 

Thanks,

Tom

20171220_224448.jpg

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I don't know, ... I get a bryozoan vibe from this. :unsure: 

 

Maybe @TqB or @DE&i or @JohnBrewer will know. 

 

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I was thinking Bryazoan, but the structure seems more Graptolite to me, however I'm struggling to find any information regarding Graptolites from this site, but a lot on Bryazoan. :blink:

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I've not heard of and can't find reference to any dendroid graptolites from there and agree it's probably a bryozoan, something like this Reteporina psygma but better images would be needed. (From the Pal Soc Monograph, Snell, 2004, Bryozoa from the Much Wenlock Limestone.)

 

5a3b810c6874e_ScreenShot2017-12-21at09_26_00.png.7fc3e0c81ba4e1b297ec9d7252c24d85.png

 

 

Tarquin

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I agree with Tarquin, I have never seen or collected graptolites from here but plenty of bryozoan fragments that look like this. It needs cleaning up a bit to get an ID.

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The true test on whether this is a Graptolite or Bryozoan would be if the fossil is preserved as a black carbon film vs. calcitic replacement. Quick easy test would be to take something sharp, like a dental tool or pin, and scratch across part of it. If it flakes off then it's probably a Graptolite since they are typically found as carbon films. If it doesn't flake then it's calcitic preservation and thus more likely to be a bryozoan.  If you don't want the invasive, potentially destructive method then look at it under a microscope. Carbon films will not show up as 3-D while calcitic preservation will.

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Hey everyone,

 

I've been avidly searching anything regarding dendroid graptolites being found at wrens nest because some part of me still believed it was - based on its morphology and film like appearance! I have news, I have just this moment stumbled across a book called 'Fossil plants - volume 2' by Albert c. Seward, with the following extract.

 

What do people think?

Screen Shot 2017-12-22 at 00.47.38.png

Screen Shot 2017-12-22 at 00.49.04.png

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the morphology ressembles that of Thallograptus arborescens  (and Coremagraptus) slightly*/**,but algal and bryozoan is frankly just as likely .....I think there's no way to tell

wihout at least more information on the taphonomy and at least an order of magnification higher.

*Mind you: this is really unadulterated hubris. Morphology is often a poor pointer to systematic affinities in branching Paleozoic organisms

 

**the stratigraphy and areal distribution of which I haven't even looked at

Tomexperimpaleozscuphycolbotanyl2010.pdf

 

specicgghitopugyytykkanguujjjiidp88humb.jpg

 

 

 

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Thank you for this in sight. :) Ill try and get some better pictures with a macro lens at a later date and see what shows up. Im not particularly knowledgable about graptolites or Bryazoan, but having slightly more knowledge in Graptolites that area it seemed liked the best place for me to start.

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8 hours ago, Tom Hughes said:

Hey everyone,

 

I've been avidly searching anything regarding dendroid graptolites being found at wrens nest because some part of me still believed it was - based on its morphology and film like appearance! I have news, I have just this moment stumbled across a book called 'Fossil plants - volume 2' by Albert c. Seward, with the following extract.

 

What do people think?

 

Screen Shot 2017-12-22 at 00.49.04.png

 

We didn't know it was a film - that certainly makes it more intriguing. :) As doushantuo says, many taxa branch like that - looking forward to more photos...

Tarquin

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Tarq,I suppose hydroid is totally out of the question?

below:genuine 3dimensionally preserved graptolites.

 

 

6acrospki56ghb.jpg

 

 

 

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Could be but I don't think I'd be able to identify a hydroid. :) 

Those are magnificent graptolites - I've got one of the erratic Silurian limestone pebbles from the Polish coast that might do that if it was etched...

Tarquin

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Not beyond the realms of possibility ,because the ones i showed are from erratics in Germany.

Wish i had those,they are indeed awesome

 

 

 

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  • 11 months later...

My guess is that the specimen in question is the bryozoa Pseudohornera.

This one is from the Ordovician, courtesy of Fossilworks, but the genus does occur in the Wenlock Limestone of the Dudley area. 

Image result for pseudohornera silurian

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