Plant or animal ?

[Rocky Stoner]

Hi folks, me again ...

Went back to the shale pit to "crack a few" in search of something new, well, you know what I mean.

There were several fossils like the one pictured. Some appeared to be straight across the bottom like a brachiopod but could have looked that way due to the break in the split.

Can you tell if this is plant or animal ?

I searched the regular sources and found little (no) relatively info.

Next time there, I'll try to get better examples.

Thanks again,

 

[westcoast]

 Looks like a brachipod but there are bivalves such as Dunbarella that are common in shale that can resemble brachiopods. Need a complete hinge line/umbo.

[fossilized6s]

I agree with Brachiopod. 

[ynot]

Looks brachiopod to Me also.

[Rocky Stoner]

One other detail that is not evident in the single (sorry) photo, these are very near to absolutely flat. Wouldn't be much room inside for brachipopd innards.

I suppose they could have been flattened somehow if in fact they are brachiopods ?

Thanks.

[Kane]

Some brachiopods could be fairly svelte, but in this case it is a question of the preservation that crushes them flat. Although not a hard and fast rule, generally speaking fossils that appear in highly compressed fissile shale tend to be more likely crushed, while those preserved in limestone tend to be a bit more robust.

[Rocky Stoner]

20 minutes ago, westcoast said:

 Looks like a brachipod but there are bivalves such as Dunbarella that are common in shale that can resemble brachiopods. Need a complete hinge line/umbo.

Image search looks very similar, THANKS for the hit !

[Brett Breakin' Rocks]

2 minutes ago, Rocky Stoner said:

One other detail that is not evident in the single (sorry) photo, these are very near to absolutely flat. Wouldn't be much room inside for brachipopd innards.

I suppose they could have been flattened somehow if in fact they are brachiopods ?

Thanks.

Yes, just as @Kane said if you look around some brachiopods can have a quite thin shape and profile but you also have to consider that this shale is a sedimentary deposit of mud that has been compressed and created under enormous pressure.  It is not uncommon for fossils in shale to be distorted heavily or compressed and essentially 'squished' under all of that weight.

 

Cheers,

Brett

[Brett Breakin' Rocks]

13 minutes ago, Rocky Stoner said:

One other detail that is not evident in the single (sorry) photo, these are very near to absolutely flat. Wouldn't be much room inside for brachipopd innards.

I suppose they could have been flattened somehow if in fact they are brachiopods ?

Thanks.

Here is a nice explanation of the process of specifically strain on the rock. Your shale might be more on the compaction side but still the same forces are involved. 

http://hudsonvalleygeologist.blogspot.com/2013/07/strained-by-stress.html

 

and a distorted trilo to boot ....

 

[Rocky Stoner]

 Stress and Strain ....... Turkey and Cheese. 

Excellent description, thank you !

4 minutes ago, Brett Breakin' Rocks said:

Here is a nice explanation of the process ..

http://hudsonvalleygeologist.blogspot.com/2013/07/strained-by-stress.html

 

and a distorted trilo to boot ....

 

 

[piranha]

Compare with: Protoleptostrophia perplana

 

 

figure from:

 

Ellison, R.L. (1965)
Stratigraphy and Paleontology of the Mahantango Formation in south-central Pennsylvania.
Pennsylvania Geological Survey, Fourth Series, Bulletin G48:1-298  PDF LINK

[Rocky Stoner]

I went back to the "pit" to look for more examples and the ones I'd seen earlier had been overexposed to the sun and disintegrated.

So I popped out a few fresh chunks and found several rather quickly, these three exhibiting the best views of the hinge-line/umbo.

I suppose the pressure would also have contributed by dilation making them thinner than a leaf.

Learned a bit today ... as I do everyday here, thanks !

(and a picture of the "pit" for kicks)

[Herb]

looks like a Miss. brachiopod, Orthotetes sp.

[Miocene_Mason]

Reminds me of protostropholepta (and other strophomenids) sorry to muddy the water further....

I've found these in the mahantango btw

[Rocky Stoner]

14 minutes ago, WhodamanHD said:

Reminds me of protostropholepta (and other strophomenids) sorry to muddy the water further....

I've found these in the mahantango btw

Interesting.

https://en.wikipedia.org/wiki/Strophomenida

quote ... "Typically the dorsal valve was either concave or flat, though occasionally it was convex; the ventral valve was convex."

One flat valve, cool.

Also, in this matrix there are small brachiopods and crinoid segments that are not distorted in the least.

 

Thanks.

... and the crinoid posted earlier was just inches away from these valves and shows now deformation.

[westcoast]

Yes. Beautiful  brachiopods. Quite large too. Another couple of interiors and exteriors of both valves and ID should get a bit clearer..but Protoleptostrophia looking good right now.

[Rocky Stoner]

5 hours ago, piranha said:

Compare with: Protoleptostrophia perplana

 

49 minutes ago, WhodamanHD said:

Reminds me of protostropholepta ....

 

Can I assume these are intended to be one in the same ?

(the latter returns nothing from a search)

Thanks !

[abyssunder]

Maybe this is the most interesting part of a story. Can somebody explain that? Recovering of predation?

 

[Miocene_Mason]

3 hours ago, Rocky Stoner said:

 

 

Can I assume these are intended to be one in the same ?

(the latter returns nothing from a search)

Thanks !

Yeah, wasnt sure of the spelling and I didn't see that comment, so in hindsight I agree with piranha!

3 hours ago, abyssunder said:

Maybe this is the most interesting part of a story. Can somebody explain that? Recovering of predation?

 

Maybe just intraspecies variation? The lines do tend to wiggle as they get bigger I've observed.