Silurian Trilobite Help

[historianmichael]

I recently collected in the Rose Hill Formation in West Virginia. I found a lot of small trilobite pieces and a couple brachiopod and pelecypod fossils. I am having some trouble figuring out what these two fossils are. Any help would be greatly appreciated. Please let me know if you need any additional photos.

 

#1- the piece at the bottom of the photo measures about 0.5 cm tall and 1 cm wide. 

 

I found a similar looking fossil below. No clue what it could be...

 

 

 

#2- the pygidium measures about 1 cm tall and 1.3 cm wide.

 

[Misha]

Neat finds whatever they are!

I am not of much help here but @piranha has lots of knowledge and information when it comes to bugs and he may know what these might be

 

Upon looking at it a bit more maybe #2 is a cheirurid cephalon?

[aek]

#2 does look cheirurid-ish. Perhaps you can prep it out a bit to reveal more?

[piranha]

Calymenidae

 

[historianmichael]

Thank you all for your fast responses. Unfortunately the sandstone does not preserve the fossils that well and I think that is all that there is.

 

@piranha Out of curiosity, is it your understanding that #1 is part of the glabella and cheek of Calymene sp.? I am trying to understand where on the anatomy of the trilobite #1 comes from. 

[piranha]

Just now, historianmichael said:

Thank you all for your fast responses. Unfortunately the sandstone does not preserve the fossils that well and I think that is all that there is.

 

@piranha Out of curiosity, is it your understanding that #1 is part of the glabella and cheek of Calymene sp.? I am trying to understand where on the anatomy of the trilobite #1 comes from. 

 

 

Correct.  The species is: Liocalymene cresapensis

 

 

Edgecombe, G.D., Adrain, J.M. 1995. Silurian Calymenid Trilobites from the United States. Palaeontographica Abt.A, 235:1-19

[historianmichael]

@piranha Same for #2? Is that Liocalymene cresapensis as well?

[piranha]

That would be my label if they were found in the same vicinity.

[piranha]

Liocalymene clintoni is also described from Rose Hill.  This species is different with a sigmoidal glabellar furrow 1p and smooth pleural area on the pygidium.

 

figures from:

 

Whittington, H.B. 1971. Silurian Calymenid Trilobites from United States, Norway, and Sweden. Palaeontology, 14(3):455-477  PDF LINK

[historianmichael]

@piranha They were found at the same locale. Thank you for the information on the difference between the two cephalons. I am aware that both types of trilobites are found in the Rose Hill formation but I had not been able to come across a good image of the cephalon of Liocalymene clintoni. I will have to go back through what I found to make sure I have labeled things correctly. Thank you again! 

[EMP]

4 hours ago, historianmichael said:

I recently collected in the Rose Hill Formation in West Virginia. I found a lot of small trilobite pieces and a couple brachiopod and pelecypod fossils. I am having some trouble figuring out what these two fossils are. Any help would be greatly appreciated. Please let me know if you need any additional photos.

 

#1- the piece at the bottom of the photo measures about 0.5 cm tall and 1 cm wide. 

 

I found a similar looking fossil below. No clue what it could be...

 

 

 

#2- the pygidium measures about 1 cm tall and 1.3 cm wide.

 

 

I just collected in the Rose Hill! I have some pictures of my finds if they'd be of any help to you identifying stuff. 

 

1. Looks like it could be a pentamurid brachiopod. 

 

2. I agree this looks like a trilobite cephalon. 

 

3. Take this with a grain of salt, as it may depend on where exactly in WV you found this, but at least in Maryland and in the adjoining areas of West Virginia (by Wills Mountain) L. clintoni is only present in the uppermost layers of the Rose Hill, which are thin bedded shales and argillaceous limestones. Your photos look to be of ironstones/sandstones from lower in the formation (there are two prominent ironstone beds in the Rose Hill, a lower one and an upper one). Trilobites are well known from those, but at least in MD L. clintoni isn't present below the upper shale layer (perhaps it's different in WV). At any rate L. clintoni has a smooth pygidium and this does not. I'd go with a Calymene sp. ID on this specimen. There's a couple of different Calymene species in the Rose Hill, but you really need a cephalon and size to differentiate between them.  

 

Say, you didn't find any shiny, black, spine like things at this site did you? I found a couple at the place I collected, and they may be acanthodian spines. I was wondering if those were just a one off occurrence or if there's more of them in the Rose Hill. 

 

Actually come to think of it, @piranha was Liocalymene cresapensis reclassified from Calymene cresapensis? I've seen C. cresapensis reported from the Rose Hill, but not L. cresapensis, and I was wondering if that's just because the report's from 1920 or if they're actually different species. 

[piranha]

28 minutes ago, EMP said:

There's a couple of different Calymene species in the Rose Hill, but you really need a cephalon and size to differentiate between them. 

 

I posted the info on how to differentiate the species -- if you take a moment to read the previous post above.

 

28 minutes ago, EMP said:

Actually come to think of it, @piranha was Liocalymene cresapensis reclassified from Calymene cresapensis? I've seen C. cresapensis reported from the Rose Hill, but not L. cresapensis, and I was wondering if that's just because the report's from 1920 or if they're actually different species. 

 

Edgecombe & Adrain 1995 reclassified it:

 

Discussion: WHITTINGTON (1971) revised the monotypic genus Liocalymene with the observation that "its relationships are obscure, for no other late Ordovician or early Silurian calymenid exhibiting similar characters [to L. clintoni] appears to have been described" (p. 474). The late Llandovery species Calymene cresapensis PROUTY, 1923, shows trends towards several of the diagnostic characters of Liocalymene, and is regarded as the plesiomorphic sister species of L. clintoni. lt is accordingly classified as Liocalymene, but it provides links to less highly modified calymenids (notably Ordovician species of Sthenarocalymene SIVETER, 1977).

 

Edgecombe, G.D., Adrain, J.M. 1995

Silurian Calymenid Trilobites from the United States.

Palaeontographica Abt.A, 235:1-19

[historianmichael]

@EMP Unfortunately I did not see any fish material at this site. It was all just sandstone. Nevertheless, you are able to find both L. cresapensis and L. clintoni in the sandstone. Here is a tiny L. clintoni pygidium I found.

 

 

I also found a bunch of thorax sections from Trimerus sp. For example, here is a piece.

 

 

 

@piranha Please let me know if you disagree with any of these identifications.

[Rexofspades]

On 7/17/2020 at 5:50 PM, historianmichael said:

@EMP Unfortunately I did not see any fish material at this site. It was all just sandstone. Nevertheless, you are able to find both L. cresapensis and L. clintoni in the sandstone. Here is a tiny L. clintoni pygidium I found.

 

 

I also found a bunch of thorax sections from Trimerus sp. For example, here is a piece.

 

 

 

@piranha Please let me know if you disagree with any of these identifications.

just hunted at rose hill formation today! did you split rock for any of these? or is it all surface finds. I'm new to finding stuff in Rose hill so i could use any pointers I can get haha. 

[historianmichael]

21 minutes ago, Rexofspades said:

just hunted at rose hill formation today! did you split rock for any of these? or is it all surface finds. I'm new to finding stuff in Rose hill so i could use any pointers I can get haha. 

These were all split out. Look for rocks that have weathered fossils on the outside and then split them open to get the fresher material. Most of my finds came from one big rock.