Mazon Creek Eurypterid Carapace ???

[Nimravis]

 

I have had these two pieces in my collection for a long time- I always have had a hard time tossing them when I come across them in their drawer because they remind me of a Eurypterid carapaces.

 

What do you think?   @RCFossils / @Rob Russell / @fossilized6s / @Peat Burns and any others that might have info. 

 

 

 

[Fossil-Hound]

If anyone would know it's @Malcolmt though in the fossil record Eurypterids only survived to the late Silurian (418 MYA). The Mazon Creek formations are much later (309 MYA) during the Pennsylvanian unless of course this is said specimen and so happens to break that trend.

[Nimravis]

13 minutes ago, Fossil-Hound said:

If anyone would know it's @Malcolmt though in the fossil record Eurypterids only survived to the late Silurian (418 MYA). The Mazon Creek formations are much later (309 MYA) during the Pennsylvanian unless of course this is said specimen and so happens to break that trend.

Eurypterids are found in the Mazon Creek biota, here is one that Ifound.

 

 

Here is one that is found in Dave's Down To Earth Rock Shops Museum-

 

[Fossil-Hound]

@Nimravis ok I'm impressed. I thought the geologic time periods where off (Silurian and Pennsylvanian). Are there Silurian formation in the Mazon Creek? What you have does look like a Eurypterid carapace but I'll leave it to the experts to supply a positive identification.

[Malcolmt]

Actually eurypterids finally kicked the bucket in the great Permian extinction 252 million years ago. They had been on a steady decline . The ones we found up here were Silurian but potential bits have definitely been found in the Devonian of Arkona up here Ontario Canada. No reason why a Mason nodule could not have a part of a eurypterid in it. We see domes seeding all the time with eurypterid bits at the center.

[Peat Burns]

They're definitely keepers, but I can't say definitively that they are eurypterid.  I can see how that crossed your mind though.

[Nimravis]

3 hours ago, Fossil-Hound said:

Are there Silurian formation in the Mazon Creek?

No there are not.

[Fossildude19]

From Wikipedia:

 

"Eurypterids, often informally referred to as sea scorpions, are an extinct group of arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago, though the group is likely to have first appeared either during the Early Ordovician or Late Cambrian period. The Eurypterida is the most diverse Paleozoic chelicerate order in terms of species, containing approximately 250 species. Following their appearance during the Ordovician, eurypterids would become major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus Eurypterus accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event and would decline in numbers and diversity until they became extinct during the Permian–Triassic extinction event (or sometime shortly before) 251.9 million years ago."

[jdp]

Eurypterids make it well into the Permian. I've collected both body fossils and trackways from the Carboniferous-Permian boundary from a few different localities. They're not particularly common after the end-devonian, but they're definitely there, particularly Adelophthalmus. Some get quite large; the trackway I collected was of a large  animal over 30 cm wide.

[doushantuo]

the specimen shown looks slightly like "Anthraconectes"(reassigned to Adelopthalmus,I believe)

[jdp]

Yeah, I think Adelopthalmus is a safe bet.

[Missourian]

Is there any visible fine detail similar to this?:

 

 

This is a segment from a rather large Adelophthalmus (Pennsylvanian)

 

[RCFossils]

As others have mentioned, eurypterid are well known from many Carboniferous localities.

To my knowledge, Adelopthalmus is the only valid eurypterid described from the Mazon Creek deposit.

There was a second type described that ultimately turned out to be a branch scar.

Mazon specimens are rarer then similar types that I have seen from from other localities in Indiana, Missouri and New Mexico.

Most Mazon specimens are only a few inches in length however I have a body section of one that would have measured close to a foot in length.

I also have a prosoma (head shield) of a very large specimen that was collected at a similar site near Carterville Illinois.

I believe it is the largest example of Adelopthalmus known.

Unfortunately, I do not think either of these specimens are eurypterid.

They do not have the right “look” and lack the scaly pattern.

They are still interesting unknowns.

[doushantuo]

I made an honest,but very very stupid mistake.This post is NOT about Nimravis's pictures.

The first pictures in this post are mystifying(odontogriphid?),and not very arthropod-like,Like RCG rightly points out

I might have to remind myself not to react immediately to a pictiure I recognize,and keep in mind to scroll to the very first post in a thread.

Asinine is the word I'm looking for,probably.

Dense might do,or plain stupid.

At this moment I'm repenting at leisure,bigtime

[Nimravis]

43 minutes ago, RCFossils said:

They do not have the right “look” and lack the scaly pattern.

They are still interesting unknowns.

That is why I never tossed them, they just had the look.

[Nimravis]

Just for eye candy and if you did not see my recent post on Mazon Creek fossils at Dave’s Rock Shop, here are both halves from his Museum.

 

[RCFossils]

This is the best example of a Mazon Creek Adelophthalmus mazonensis that I have in my collection.

[RCFossils]

This is a body section of a very large specimen

[RCFossils]

This is the headshield of my specimen from Carterville Illinois.

I placed it next to an 8” example of Eurypterus remipes (Silurian) from New York.

The Adelophthalmus prosoma is nearly double the size!

I would estimate that the animal would have measured around 16” in length!

[RCFossils]

Carterville Eurypterid prosoma.

[Guest11596]

!

 

 

 

 

 

 

 

[Nimravis]

@RCFossils very nice examples - Thanks for sharing.

[deutscheben]

That Carterville eurypterid is amazing, @RCFossils!

[RCFossils]

On 10/29/2018 at 10:06 PM, Nimravis said:

Eurypterids are found in the Mazon Creek biota, here is one that Ifound.

 

 

Here is one that is found in Dave's Down To Earth Rock Shops Museum-

 

I know someone who can prep out the head (and possibly appendages) of your eurypterid.

PM me if you are interested and I can send you his contact information.

[Nimravis]

1 hour ago, RCFossils said:

I know someone who can prep out the head (and possibly appendages) of your eurypterid.

PM me if you are interested and I can send you his contact information.

Thanks, I will think about it.