Eurypterid

[EscarpmentMary]

I was working at my desk today when one of my fossils caught my eye. I picked it up and thought that looks like a  Tully Monster, but a quick check on the internet and I realized too small and not my geological time period, the Tullimonstrum belongs in the Pennsylvanian period. 300 million years ago, too young, there you go Illinois US. So I’m thinking a part of Eurypterid, or sea scorpion, they were around during theSilurian. What do you all think?

 

[Thecosmilia Trichitoma]

Sorry but I am seeing mineral veins, not fossils of any kind.

[LabRatKing]

Yep. No fossil here, just some grainy layers with calcite interspacing.

[JohnJ]

There may be remnants of an eroded coral...

 

[EscarpmentMary]

Yes thank you JohnJ I agree, to the others saying “ it looks like nothing to me” is not conducive!

[Kane]

For eurypterids, these are typically found in a few Silurian formations. The Bertie Formation is by far the most productive in Ontario for finding eurypterids, particularly at the Ridgemount Quarry in the Fort Erie area. There have been some found in the Eramosa Member, but those outcrops are restricted to working quarries. 

 

This is a classic put together by Copeland and Bolton -- both of whom studied the Silurian of Ontario extensively: https://archive.org/details/fossilsofontario03bolt

 

There is a late Ordovician eurypterid up in Manitoulin, just at the boundary with the early Silurian. Here is the paper by Stott et al: https://www.researchgate.net/publication/228349255_A_new_eurypterid_Chelicerata_from_the_Upper_Ordovician_of_Manitoulin_Island_Ontario_Canada

 

The likelihood of finding a eurypterid in your local material is very low, and I don't think any have been reported. 

[Fossildude19]

20 minutes ago, EscarpmentMary said:

... to the others saying “ it looks like nothing to me” is not conducive!

 

People are just letting you know what they think you have. 

Adding that they are not seeing what you are seeing is kind of part and parcel, here.    

 

[Malcolmt]

Others have said but definitely not eurypterid.... Here are a few examples

 

 

 

 

[Kane]

Oh, Malcolm, you show off.  

 

I've been fortunate to see these in person. And these are hardly representative of all the ones he's found over the years. 

[Malcolmt]

Unfortunately it is somewhat doubtful that I will be finding many more as the source is pretty much tapped out unless there is an expansion of the site that will remove 30 to 50 feet of overburden

[Kane]

Just now, Malcolmt said:

Unfortunately it is somewhat doubtful that I will be finding many more as the source is pretty much tapped out unless there is an expansion of the site that will remove 30 to 50 feet of overburden

Yeah, I heard they were digging in the wrong places now.  But you and others made hay while the sun was still shining. 

[Top Trilo]

12 minutes ago, Malcolmt said:

Unfortunately it is somewhat doubtful that I will be finding many more as the source is pretty much tapped out

I wonder why, that's an incredible collection

[Malcolmt]

The site had a layer that was productive for eurypterids that was 6 inches to 2 feet thick. The quarry has now blasted through that layer pretty much everywhere and is now excavating and blasting below that layer. They would have to widen the quarry to expose that layer again. Over the years literally hundreds of collectors were allowed in to save these wonderful creatures thanks to the generosity and realization of the scientific value of these wonderful creatures by the quarry management and owners.. Museums all over the world are fortunate to have specimens collected there. One of  he worlds best acanthodian fish was found there and donated to The ROM . The collectors at the site were for the most part very willing to make sure that anything of real scientific interest ended up at a museum or university.

[jpc]

darn... I had this place on my bucket list.  

 

[EscarpmentMary]

Thanks for the response all, really it was an innocent question really, I still feel it’s a fossil of some sort, the fossils of this area seem to come in a Lagerstatte of heavily calcified fossils, I have many ideas about the changing environment some 500 million to 350 million years ago. There it was, up against an ancient coral bloom.  Quite beautiful, I will hold it in my collection, I see a tail, segmented shell and perhaps a claw. My only resource is you all. Probably need to take a fossil break 

[Kane]

1 hour ago, EscarpmentMary said:

Thanks for the response all, really it was an innocent question really, I still feel it’s a fossil of some sort, the fossils of this area seem to come in a Lagerstatte of heavily calcified fossils, I have many ideas about the changing environment some 500 million to 350 million years ago. There it was, up against an ancient coral bloom.  Quite beautiful, I will hold it in my collection, I see a tail, segmented shell and perhaps a claw. My only resource is you all. Probably need to take a fossil break 

Unfortunately, none of the fossils you have shown us come from a Lagerstatte. In your area, the only reported Lagerstatte area is in a few of the Wiarton quarries. Have another look at the work by Tetreault. 

[EscarpmentMary]

OK I take everything backKane sent me a BOOK! a paper and Malcolmt sent me photos. I'm doing a happy dance in my living room!!! Thankyou so much, so glad I joined the fossil forum. 

[Notidanodon]

@Malcolmtjust a few examples

[EscarpmentMary]

[EscarpmentMary]

[EscarpmentMary]

[EscarpmentMary]

I have been reading and learning and I'm thinking my Eurypterid Chelicerata is the new species identified in November 2005 as Orcanopterus manitoulinenisis. 

I will try and present my case here:   The above map shows where this particular species was found in the strata.  My sample was found in Big Bay, Ontario Canada, I have included photos of Big Bay, taken on that day last November. I picked it off the beach surface. So many water washed stones as you can see. I often brought my children here when they were small, there is a General Store up the road and we along with all the other summer people would go there for ice cream and wander down to the beach. I don't usually keep the stones we find there because to tell you the truth I want to leave them there for other future generations to find and wonder at. I saved that rock of the Eurypterid however,  for the lovely coral bloom. Now I have used the term Laggerstatte and Kane has rightly warned me that the Eromasa Lagerstatte is not in this area or Owen Sound for that matter so I have included the map of Tetreault's showing the location of said Lagerstatte.

The reason I do use the term however is because Tetreaults description is calcareous, chalky, and containing calcium carbonate which to me describes the look of this fossil. In the paper on the Orcanopterus manitoulinenisis the authors describe this particular species as difficult to preserve as fossils due to their thin unmineralized chitinous cuticle leaving me to believe only a preservation technique such as a calcareous effect high in calcium carbonate could this be achieved but I am not a chemist.  How did it get there? The appearance of the water washed stones would suggest to me that storms and inter tidal forces would carry these already fossilized pieces to the beach.  Lastly, the diagram at the top is the drawing by the authors of the paper Orcanopterus manitoulinensis, I used the telson shape and the paddle as a way to match them up however the Big Bay fossil has, in my opinion, if you look carefully, a perceptible chelicerae which is not included in their diagram.

[Kane]

I'm sorry, but the specimen you presented is heavily eroded coral on weathered dolostone.

 

It is highly improbable (as in winning the Lotto 649 jackpot three times in a row improbable) it is Orcanopterus manitoulinensis as the lithology is not in any way similar to your piece. I visited the specific locations where these were reported, as one of the authors is a friend of mine. The lithology is distinctively platy, occurring in a very thin banded horizon. Your piece is not platy, wrong texture, wrong kind of rock, and wrong colour. The horizon in which these appear is a heavily recessive unit, which means it would not survive transport, but would erode to nothing en route.

 

You may be overthinking this. Occam's razor would strongly suggest this piece belongs to the local Silurian strata, and most of the washed in rocks were transported relatively recently in geologic temporal terms. 

[Malcolmt]

Must be nice to have been to those locations........ and even nicer to know one of the authors....

[EscarpmentMary]

I never thought about the strata, you have a good point there, oh well, nothing ventured as they say. I really learned a lot though, thanks so much.