I Think These Are Some Sort Of Trace Fossil? And Am Wondering What Exactly They Are Burrows? Trackways? And What May Have Made Them?

[claire01]

I have come across several of them now and can't find anything that matches up with them and still fits my Cretaceous area. Does anyone know what they might be? Thanks very much for any help

. This one is Approx 3.5" x .75" (the rock itself is slightly larger)

Paper plate for scale:

One more, but I have several others:

Or am I completely off the mark?

[tmaier]

I vote "YES" on all of those specimens. They are burrows.

[claire01]

Thank you! What made them? What would you call these particular ones? I can't find a good match.

[tmaier]

Wait for more opinions. I normally go no further than to say they are a trace, because the source of most trace are unknown or wild guesses in the literature.

Were there any context fossils, that would give clues about the environment?

[claire01]

I was expecting them to be either crab or shrimp related, but they look very different from the ones I have been able to find online. These that Ive found, to me, look very similar to some trilobite trackways I ran across while trying to figure out just what they were, but that doesn't fit my area at all.

*Edited to say: I have examples of burrows that I am reasonably sure are either crab or shrimp and they look different.

Edited September 8, 2014 by claire01

[caldigger]

To me they look like something burrowing and excreting the silt behind it as it went.

[BobWill]

The big piece on the paper plate looks like an ammonite section with 2 very worn ribs projecting up from an umbilical margin with inner whorls missing. Could we see more views of anything that shows any details or curved surfaces on any of those?

[kauffy]

because the source of most trace are unknown or wild guesses in the literature.

I disagree, most of the literature on trace fossils evaluates the structural components of the ichnofossil and deduce the mechanisms by which a certain track could be made. From this there are many modern analogues which can be assumed, for the most part though trace fossils are classified by the type of actions being performed to create them, ie burrowing, feeding, resting ect.

One could look at thousands of interesting articles/ papers which put forth great information on different traces in different sedimentary environments... Unfortunately you'd need to be pretty familiar with the different structures to identify them correctly. Which I am not!

I kinda see "ammonite" structure in the first one, but I am still leaning towards trace fossil until we see some more angles . Pretty interesting non the less, thanks for sharing.

[fossilcrazy]

My picture doesn't give age ranges, but some similar traces to compare. If you notice; no speculations are made on what made the traces. The only thing scientists have to go on, is comparing extinct species to extant species. Actual body fossils are needed to make good conclusions.

[kauffy]

Its simple. But a great reference, thanks fossilcrazy

Edited September 9, 2014 by kauffy

[claire01]

I'm pretty sure they are burrows, I have found a number of ammonites here and don't think that's what these are, BobWill, but I will spend a little more time looking them over for signs that that's what they might be and will post some more pictures in the morning when the light is better. Thank you!

It would make sense for them to be ghost shrimp burrows but I see no evidence of shrimp coprolites on these and I would expect to see at least one or two clinging to them somewhere. I have found a good many of what I believe to be shrimp burrows and they don't have this distinctive shape. This is all pure guesswork based solely on my observations of the area though, so please correct me if I'm wrong.

Thanks kauffy and fossilcrazy, just seeing your responses

Edited September 9, 2014 by claire01

[kauffy]

I'm pretty sure they are burrows, I have found a number of ammonites here and don't think that's what these are, BobWill, but I will spend a little more time looking them over for signs that that's what they might be and will post some more pictures in the morning when the light is better. Thank you!

It would make sense for them to be ghost shrimp burrows but I see no evidence of shrimp coprolites on these and I would expect to see at least one or two clinging to them somewhere. I have found a good many of what I believe to be shrimp burrows and they don't have this distinctive shape. This is all pure guesswork from my observations of the area though, so please correct me if I'm wrong.

I think your reasoning (guesswork and observations) are fine, you are the one with them in hand with the best view!

Keep in mind that you can have many different species of marine crustacean which behave differently in the same environment, especially in any diverse ecosystem different organisms make use of different niches. With this comes the great possibility that there are other arthropods (besides a ghost shrimp) which may behave/burrow differently.

Again as others and I have stated scientists tend to shy away from identifying ichnofossils by what animal produced them without direct association, more so the behaviour they exhibit and mechanisms used to create them.

Have you done a google scholar search on the area with "trace fossils" included? Perhaps this may turn up something relevant.

Cheers

Chris

Edited September 9, 2014 by kauffy

[claire01]

Thanks Chris, I think I can honestly say I have spent more time researching and puzzling over these than a good many of my other fossil finds. Not sure why I find them so intriguing. Tomorrow I will post some pictures of the other burrows I have. Thanks!

[tmaier]

I disagree, most of the literature on trace fossils evaluates the structural components of the ichnofossil and deduce the mechanisms by which a certain track could be made. From this there are many modern analogues which can be assumed, for the most part though trace fossils are classified by the type of actions being performed to create them, ie burrowing, feeding, resting ect.

I said "guess", but you disagree, and the proper word should be "assume".

[kauffy]

I said "guess", but you disagree, and the proper word should be "assume".

I 'guess' i just interpreted your first comment as suggesting the literature was inadequate at describing trace fossils, and they were all just taking wild stabs at what they were. My point was that the literature is quite sufficient, but yes I agree to "guess" or to "assume" what animal made them is the same thing...

[tmaier]

I'm an engineer, and we are trained to never use the word "guess" or "assume". We say "best approximation" or "highly correlative". It sounds more like we know what we are talking about.

But... privately we call it a W.A.G.

[claire01]

Okay, a few more pictures:

These are what I have assumed were burrows collected from the same area which are on an 8 " x 8" white surface:

Shoot, my files are too large so I'm skipping down to another comment for the rest of the photos, sorry.

[claire01]

And here are images of the ones in question on the same 8" x 8" surface:

The one in the upper right hand corner may have something inside:

I'm working on cleaning it up, but it may just be that little fragment and nothing more.

[tmaier]

Finding a burrow with the creature in situ might be very significant, especially if it has not been found before.

It is rare.

[PFOOLEY]

Modern Ghost Shrimp traces...

...from Life Traces of the Georgia Coast.

[tmaier]

As you work to clean it up, take a series of photos along the way just in case tragedy strikes and it crumbles. At least you will have a record of "the one that got away" and possibly have a guide to how to put it back together again.

Edited September 9, 2014 by tmaier

[tmaier]

And if it really looks like some burrowing type of creature, I would stop and consult a professional paleontologist to see how significant it is, before proceeding too far. Then they could take it from there (but you would have to donate it).

[claire01]

PFOOLEY- so not a burrow, but a trackway? That image is dead on. Would this have to have been made on the surface, not underwater? I ask because in the past I have found what looked to me like bird track imprints, but they were dismissed as not possible for my Cretaceous shallow sea environment. The tracks(?) I found and these new trackways were found at the top of my hunting spot that slopes down to a lake and I think are therefore from a more recent period. I have long believed that in this particular spot were fluvial? alluvial? deposits that made a trackway find not out of the realm of possibilities. But that may all just be wishful thinking on my part. It would open up a lot of possibilities, though. Someone reign me in if I'm talking crazy, though

[tmaier]

That's why I was asking about fossils in context... what were the neighbors like at this time?

[tmaier]

Also, that image of the ghost shrimp trace is a feeding burrow, the animal is digging into the sediment to find food.