Two Mazon Creek Mystery Fossils

[Mark Kmiecik]

Here's a couple that I have no clue on ID. I'm asking the usual gang to help with ID, and anyone else with an educated guess.

@connorp @fiddlehead @deutscheben @Nimravis @RCFossils @stats

 

 

 

Edited February 7, 2022 by Mark Kmiecik

[Nimravis]

The first one looks shrimpy to me and the other looks like a poorly preserved piece of flora.

[deutscheben]

B0012 looks like Mazopherusa prinosi, the fan worm. They are often found bunched in groups like this, and the segmentation and mineral preservation look similar as well to samples I have.

[stats]

2 hours ago, Mark Kmiecik said:

Here's a couple that I have no clue on ID. I'm asking the usual gang to help with ID, and anyone else with an educated guess.

@connorp @fiddlehead @deutscheben @Nimravis @RCFossils @stats

 

 

 

 

The first looks like a shrimp, probably a molt. 

 

The second is a fan worm.   Braceville?  It could be multiple individuals, but I have seen one worm the was wound around inside a concretion.  It makes the concretion break up in multiple planes.

 

Cheers,

Rich

 

 

[Mark Kmiecik]

On 2/7/2022 at 6:12 PM, stats said:

The second is a fan worm.   Braceville?

 

No, I found that in a creek.  Thanks for the info. The possible shrimp molt I found at Braceville.

[Mark Kmiecik]

2 hours ago, stats said:

It could be multiple individuals, but I have seen one worm the was wound around inside a concretion.

 

It does compare favorably to a fan worm colony shown in The Mazon Creek Fossil Fauna, Wittry 2012, p. 169, fig. 169.4.

Edited February 8, 2022 by Mark Kmiecik
added info

[fiddlehead]

Based on the tail shape and its relatively large size to the animal, in my opinion the "shrimp" is probably a Lobetelson mclaughlinae. The second fossil is a mass of similar sized sphenopsid cones. In the Mazon Creek area, the only recognized (known) cone form of this size and grows in mass on the same branch is Mazostachys pendulata. 

 

Hope this sheds some light,

Jack

[Mark Kmiecik]

7 hours ago, fiddlehead said:

Based on the tail shape and its relatively large size to the animal, in my opinion the "shrimp" is probably a Lobetelson mclaughlinae. The second fossil is a mass of similar sized sphenopsid cones. In the Mazon Creek area, the only recognized (known) cone form of this size and grows in mass on the same branch is Mazostachys pendulata. 

 

Hope this sheds some light,

Jack

 

Thank you, Jack. As usual, my ID's are far from correct. I truly appreciate your time and input, sir!

[stats]

15 hours ago, fiddlehead said:

Based on the tail shape and its relatively large size to the animal, in my opinion the "shrimp" is probably a Lobetelson mclaughlinae. The second fossil is a mass of similar sized sphenopsid cones. In the Mazon Creek area, the only recognized (known) cone form of this size and grows in mass on the same branch is Mazostachys pendulata. 

 

Hope this sheds some light,

Jack

Wow!  I need to look at a few of my "worm" colonies.  What led you to that conclusion?  Where it was found?

 

Thanks!

 

Cheers,

Rich

[fiddlehead]

8 hours ago, stats said:

Wow!  I need to look at a few of my "worm" colonies.  What led you to that conclusion?  Where it was found?

 

Thanks!

 

Cheers,

Rich

Unlike today, Paleozoic cones contained no seeds or pollen, only spores. And all sphenopsid cones are cylindrical, and produce evenly spaced whorls of thin sterile bracts. These protect spore sacs containing exclusively tiny microspores. Cones when young have tightly closed bracts appearing annulated with rounded and even inner segments. A possibly closed cone can be seen on the top fossil half, at the bottom left. It has the sterile bracts still in the enrolled position.  Most, if not all the other cones seen here have opened to some extent and the sterile bracts have attempted to straighten. And if uncompressed, the bracts acutely point toward the distal end of the cone. Often associated with open cones are dispersing spores. These are often found in a soft kaolinite surrounding the cone as seen here.

  The objects seen on this rock are linear, cylindrical and have evenly spaced annulations. I believe some can be seen producing bracts emerging from the annulation constriction. "Worms" like the polycheates (bristle worms) found at Mazon Creek produce setae which might have superficial resemblance to unrolled cone bracts. But setae on worms are borne in a bundle from the center of the segment, not from the annulation constriction. The previously mentioned Fan Worm, doesn't  produces any bristle-like structures along the body.

 

Hope there is some clarity in this,

Jack  

[flipper559]

1 hour ago, fiddlehead said:

Unlike today, Paleozoic cones contained no seeds or pollen, only spores. And all sphenopsid cones are cylindrical, and produce evenly spaced whorls of thin sterile bracts. These protect spore sacs containing exclusively tiny microspores. Cones when young have tightly closed bracts appearing annulated with rounded and even inner segments. A possibly closed cone can be seen on the top fossil half, at the bottom left. It has the sterile bracts still in the enrolled position.  Most, if not all the other cones seen here have opened to some extent and the sterile bracts have attempted to straighten. And if uncompressed, the bracts acutely point toward the distal end of the cone. Often associated with open cones are dispersing spores. These are often found in a soft kaolinite surrounding the cone as seen here.

  The objects seen on this rock are linear, cylindrical and have evenly spaced annulations. I believe some can be seen producing bracts emerging from the annulation constriction. "Worms" like the polycheates (bristle worms) found at Mazon Creek produce setae which might have superficial resemblance to unrolled cone bracts. But setae on worms are borne in a bundle from the center of the segment, not from the annulation constriction. The previously mentioned Fan Worm, doesn't  produces any bristle-like structures along the body.

 

Hope there is some clarity in this,

Jack  

Very nice explanation Jack !! Thank you !!

 

Phil

[deutscheben]

Yeah, thanks for the explanation. They are a dead ringer for fan worms on first glance, but I think I see the differences you are referring to. It would also make more sense for it to be a plant knowing that it came from the river.

[Mark Kmiecik]

14 minutes ago, deutscheben said:

Yeah, thanks for the explanation. They are a dead ringer for fan worms on first glance, but I think I see the differences you are referring to. It would also make more sense for it to be a plant knowing that it came from the river.

 

I've seen a shrimp found in the creek by a friend of mine on her first trip and I'm the one who took her there to collect. Beginner's luck I guess. 

[stats]

12 hours ago, fiddlehead said:

Unlike today, Paleozoic cones contained no seeds or pollen, only spores. And all sphenopsid cones are cylindrical, and produce evenly spaced whorls of thin sterile bracts. These protect spore sacs containing exclusively tiny microspores. Cones when young have tightly closed bracts appearing annulated with rounded and even inner segments. A possibly closed cone can be seen on the top fossil half, at the bottom left. It has the sterile bracts still in the enrolled position.  Most, if not all the other cones seen here have opened to some extent and the sterile bracts have attempted to straighten. And if uncompressed, the bracts acutely point toward the distal end of the cone. Often associated with open cones are dispersing spores. These are often found in a soft kaolinite surrounding the cone as seen here.

  The objects seen on this rock are linear, cylindrical and have evenly spaced annulations. I believe some can be seen producing bracts emerging from the annulation constriction. "Worms" like the polycheates (bristle worms) found at Mazon Creek produce setae which might have superficial resemblance to unrolled cone bracts. But setae on worms are borne in a bundle from the center of the segment, not from the annulation constriction. The previously mentioned Fan Worm, doesn't  produces any bristle-like structures along the body.

 

Hope there is some clarity in this,

Jack  

Thanks for the great explanation, Jack!

 

Cheers,

Rich