New Mazon Creek Collection

[bigred97]

Thanks, @deutscheben! When it opened during freeze-thaw, I saw that there was a crack all the way around, and I brought it to my wife to open since she was the one who picked it out of Mazon Creek. She was thrilled when she saw it, and so was I! Chris

[bigred97]

Here is an Achistrum, or sea cucumber, that I found last year at Pit 11. I really like this one as it has the best mouth ring of any sea cucumber I've found, and the gray color is really interesting. Unfortunately, even though I opened this through freeze/thaw, the concretion is very delicate. As I was admiring it the day after it opened, the left half just fell apart into 2 pieces! I wasn't even touching it. Then the other piece broke into 3 pieces when I picked it up. Very disappointing, but I used a little crazy glue to stick it all back together and it didn't turn out too bad.

[bigred97]

Here is another I found in Pit 11 last year. Could this be Palaeocaris typus? It is very small, not even 2 cm for the whole concretion. I'm mostly thinking Palaeocaris due to the size and the 4 antennae, but if someone can give a positive identification I would be grateful. Chris

[RCFossils]

11 hours ago, bigred97 said:

Here is another I found in Pit 11 last year. Could this be Palaeocaris typus? It is very small, not even 2 cm for the whole concretion. I'm mostly thinking Palaeocaris due to the size and the 4 antennae, but if someone can give a positive identification I would be grateful. Chris

   

  

It is definitely a syncarid.

can you get a good close up picture of the telson?

I am leaning more towards Acanthotelson.

[fossilized6s]

Nice collection. Did you ever happen to get your fish cleaned up? 

[deutscheben]

That shrimp is a little gem, I love how distinctive the preservation is, with the clear legs, antennae and telson. 

[bigred97]

Thanks, @deutscheben! I couldn't believe when I first saw it, I really didn't expect to find anything in a concretion so small. And it looks like it could crawl right off the rock!

@RCFossils here is another picture, this was the best I could do tonight. I'm having trouble getting a good picture that is closer, but just let me know if this isn't any better and I'll keep trying! Thanks for your help! Chris

 

 

[bigred97]

@fossilized6s I haven't done anything to the fish. I talked to a professional who said, if you like it the way it is, I would recommend you leave it that way to ensure you don't accidentally make it worse. So that's what I'm doing for now. Chris

[bigred97]

Hi @RCFossils, here are a few more pics of the syncarid, including two that I took using my digital microscope. I'm still not incredibly happy with these pictures but I think this is the best I can do right now. Can you see anything that helps you positively identify it? What exactly are you trying to find? Thanks for taking a look! Chris

 

[bigred97]

Last one - 

 

[bigred97]

I wanted to post one more thing tonight, what I think may be a specimen of Octomedusa pieckorum. Can someone confirm or dash my hopes and dreams? Haha. It doesn't have the characteristic mouth opening, although it seems like that is perhaps not always found. And this specimen appears to only have 2, maybe 3, of the 8 total tentacles. Still, it seems like this would be a pretty rare find. Found in Pit 11. 

And whether this is Octomedusa or not, everyone should really see @RCFossils excellent topic on this species as part of his "Best of the Best" series for some specimens that are truly drool-worthy! Chris

[deutscheben]

Yes, I would definitely say that's an Octomedusa- nice! The one I have doesn't have all 8 tentacles either. 

[RCFossils]

Yes, it is an Octomedusa!

 

[RCFossils]

14 hours ago, bigred97 said:

Last one - 

 

Thanks for the additional pictures.

This is an Acanthotelson.

[bigred97]

Thanks @deutscheben and @RCFossils! I'm very excited about the Octomedusa! Nice to cross another species off the list.

 

Also thanks @RCFossils for identifying the syncarid. Is this a baby, then? All the specimens shown in Jack Wittry's book look bigger, which is why I was leaning toward Palaeocaris. And what did you see in the picture that made your ID possible? Just trying to increase my knowledge, if you have some time to share.

 

Chris

[Mark Kmiecik]

Octomedusa pieckorum. I have one with zero tentacles showing, but the mouth parts are prominent. Maybe if we glue them together and paint in six more arms . . . .

 

I'm leaning towards Acanthotelson stimpsoni, due to its slimmer profile and the structure of the telson.

[bigred97]

Yes @Mark Kmiecik we can do fossil mash-ups! Maybe my fish can be attacking it?

Thanks for the thoughts on the Acanthotelson. I think that is a first for me as well, although I have two other small shrimp-like fossils to post next - maybe I have more!

[RCFossils]

58 minutes ago, bigred97 said:

Thanks @deutscheben and @RCFossils! I'm very excited about the Octomedusa! Nice to cross another species off the list.

 

Also thanks @RCFossils for identifying the syncarid. Is this a baby, then? All the specimens shown in Jack Wittry's book look bigger, which is why I was leaning toward Palaeocaris. And what did you see in the picture that made your ID possible? Just trying to increase my knowledge, if you have some time to share.

 

Chris

I would not label the shrimp as a baby but it is a little smaller then average.

The easiest way to tell the difference between Palaeocaris and Acanthotelson is the telson. Palaeocaris has a more fan shaped telson where as Acanthotelson has multiple spines that project. There are other differences but you need to have a well preserved specimen to identify.

It is true that Acanthotelson can grow larger then Palaeocaris but Acanthotelson are rarely found over 2". The large Acanthotelson in the Wittry fauna book is actually my specimen and is one of the largest that have been found.

[bigred97]

Thanks for the information, @RCFossils! 

 

[Mark Kmiecik]

20 hours ago, RCFossils said:

I would not label the shrimp as a baby but it is a little smaller then average.

Perhaps a troublesome teen? 

[bigred97]

My oldest son just turned 11, I have a few years to go before I have a troublesome teen! LOL

[bigred97]

Here is one I found opened. I could tell there was something there, and it looked like some type of little shrimp. But there was a lot of calcite. It was thick and I found lots of it would flake off if I was careful and worked under magnification. I could perhaps do more work on it, although I think the easiest to remove pieces are already gone, and what remains will be a little trickier to get off. Also, the fossil plane, including the fossil itself is very black and that made it somewhat difficult to photograph, although I think these turned out pretty good - you just don't see the 25 others I had to delete! Found in Pit 11. I think it sort of looks like Hesslerella shermani, although I suppose this could also be another Acanthotelson stimpsoni?

[Tidgy's Dad]

Love the Octomedusa.

 

[bigred97]

Thanks, @Tidgy's Dad!!!

[bigred97]

Here is the other shrimp-like fossil I found open in Pit 11. Again it's very small and I found it already opened. It's sort of red-colored. I would guess another Acanthotelson.