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Unidentified Patterned Fossil


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#21 non-remaniť

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Posted 23 November 2009 - 08:58 PM

I don't have all the answers, but the fossil in question comes from an extremely reworked layer and this might be obscuring some original detail. The size and shape of the pellets does seem more akin to Ophiomorpha burrow linings in which callianassid shrimp are suspected of lining their burrows with agglutinated pelletoidal sediment for stability, but the specimen is much smaller than common Ophiomorpha burrows.

IMG_0072-edit.jpg

Looking at my first picture a little closer... it looks like there is quite a bit of variation in my stool sample. Maybe slightly different critters? A couple small pieces seem to have the rounded edges like Daryl's specimen.

but hang on. i mean, ya'll may well be onto the right answer. but what's weird about the specimen in question, if those are coprolites, is the uniformity of them. they all seem almost exactly the same length and diameter, and the ends are rounded just so. the comparative material posted has much greater variance between individual poops.


Edited by toothpuller, 23 November 2009 - 09:04 PM.

---Wie Wasser schleift den Stein, wir steigen und fallen---

#22 Daryl McEwen

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Posted 24 November 2009 - 12:32 AM

Umm Auspex, illustrations can be deceiving :) , Cretaceous Ghost shrimp burrows are usually several inches in length. I've been viewing this for a while and I am stumped. I seriously doubt that this is a "mass of coprolites," but I still can't offer a knowledgable guess as to what it really is.

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Holy crap, you're Don Miller? Your guys' book was the first one I purchased before I really started getting into hunting. Its also the most well-rounded text on fossils I've been able to find to date. Thanks for all the great info!

#23 Guest_Smilodon_*

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Posted 24 November 2009 - 01:09 AM

Holy crap, you're Don Miller? Your guys' book was the first one I purchased before I really started getting into hunting. Its also the most well-rounded text on fossils I've been able to find to date. Thanks for all the great info!


Why than you, than you vurry much
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Seriously, Daryl, thank you. It's nice to GET an attaboy once in a while. :)

#24 Carl

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Posted 24 November 2009 - 11:41 AM

i have to ask the obvious question. why do the coprolites of "callianassid" shrimp have internal structure?


Modern and fossil fecal pellets from ghost shrimp are easily identified by the bilaterally symmetrical arrangement of two groups of canals (a.k.a. haemorrhodilates) that run the length of the pellets parallel to the long axis. These canals derive from projections extending from the posterior margin of the rear gut that leave their mark on the still-fluid feces as it travels past them. These projections likely divert larger particles in the feces, which might irritate the tissues of the shrimp, away from the pellet edges. The pattern of canals is species-specific and aids ecologists studying modern ecosystems in identifying the pelletís producers. These canal patterns are very obvious in the fossil forms as well.

#25 Carl

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Posted 24 November 2009 - 11:43 AM

I just this moment received my copy of "Discovering Fossils" (from Miller's Fossils, and signed by both authors B) ), and on page 168 is a drawing that looks just like your fossil! It is identified as Ophiomorpha nodosa, the burrow of a ghost shrimp (Cretaceous to Pleistocene).


Ophiomorpha is much larger than this, never phosphatic in preservation, and the bumps are circular rather than elongated. The irony is that the same animal makes both structures!

#26 Carl

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Posted 24 November 2009 - 11:46 AM

but hang on. i mean, ya'll may well be onto the right answer. but what's weird about the specimen in question, if those are coprolites, is the uniformity of them. they all seem almost exactly the same length and diameter, and the ends are rounded just so. the comparative material posted has much greater variance between individual poops.


True, the comparative material posted has more variation in size. They are both examples of invertebrate coprolite masses, just clearly different species. Whatever made the coprolites in the original post must've made them in a very orderly fashion, like deer.

#27 Carl

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Posted 24 November 2009 - 11:49 AM

Looking at my first picture a little closer... it looks like there is quite a bit of variation in my stool sample. Maybe slightly different critters? A couple small pieces seem to have the rounded edges like Daryl's specimen.
[/quote]

Now THESE look much more like callianassid coprolites. They have the rod shape with the broken ends perpendiclar to the long axis. The one on top is especially convincing because the lengthwise section shows the canals. Very nice examples!

#28 Auspex

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Posted 24 November 2009 - 12:21 PM

These are details undreamed of by me!
Thank you for lighting a candle in the dark room of my knowledge :)

"There has been an alarming increase in the number of things I know nothing about."
-Ashleigh Ellwood Brilliant


#29 non-remaniť

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Posted 24 November 2009 - 08:54 PM

Thanks for the detailed information Carl. Interestingly, one of my pieces has some chitinous material attached to the coprolite/matrix mass. Its just a small patch, way too small for me to make an ID from, but I suppose it could be associated. Also I was going to comment on the phosphate preservation of the original specimen not jiving with a burrow (at least in my limited amateur experience) but then I remembered I just found this piece which sure looks like a phosphatic burrow to me. What do you think?

.5" wide
IMG_0074-edit.jpg

IMG_0075-edit.jpg

associated?
IMG_0068-edit2.jpg

Edited by toothpuller, 24 November 2009 - 08:56 PM.

---Wie Wasser schleift den Stein, wir steigen und fallen---

#30 erose

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Posted 25 November 2009 - 08:48 AM

Ophiomorpha are interesting in that it reflects as much about the sediment as the critter. At Big Brook you can go upstream and see another type of burrow called Thallianasoids (SP?) that is also made by Callianasid shrimp. But those are smooth sided. The sediment didn't need reinforcing with agglutinated pellets. In a few formations here in Texas we find a burrow called Spongeliomorpha which clearly shows longitudinal scratch marks where the critter dug through the sediment. These are also believed to be made by Callianasids.

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#31 Carl

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Posted 25 November 2009 - 08:55 AM

Thanks for the detailed information Carl. Interestingly, one of my pieces has some chitinous material attached to the coprolite/matrix mass. Its just a small patch, way too small for me to make an ID from, but I suppose it could be associated. Also I was going to comment on the phosphate preservation of the original specimen not jiving with a burrow (at least in my limited amateur experience) but then I remembered I just found this piece which sure looks like a phosphatic burrow to me. What do you think?

.5" wide
IMG_0074-edit.jpg

IMG_0075-edit.jpg

associated?
IMG_0068-edit2.jpg


I realized after writing that that saying they're never phosphatic was probably too strong a wording. As any of us fossil dweebs knows, practically anything is possible in the fossil record. I do think that the first and second pictures just posted are of a burrow, and, indeed, it looks fairly phosphatic.

Edited by Carl, 25 November 2009 - 08:56 AM.


#32 Carl

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Posted 25 November 2009 - 08:57 AM

Ophiomorpha are interesting in that it reflects as much about the sediment as the critter. At Big Brook you can go upstream and see another type of burrow called Thallianasoids (SP?) that is also made by Callianasid shrimp. But those are smooth sided. The sediment didn't need reinforcing with agglutinated pellets. In a few formations here in Texas we find a burrow called Spongeliomorpha which clearly shows longitudinal scratch marks where the critter dug through the sediment. These are also believed to be made by Callianasids.

Carl, you still in NYC? Send me a PM e-mail.


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#33 Guest_Smilodon_*

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Posted 30 November 2009 - 07:44 PM

Don, you could check the fossil against the description of Halyminites
major in the Horace Richards 1958 monograph (Part I, Page 42, Plate
9). It's a form taxon for burrows, and your specimen generally
resembles the ones illustrated, although it is small and the markings
somewhat differently arranged. I've seen a number of them over the
years, but they are not so common as the text seems to indicate.


From Dave Parris

#34 Haddy

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Posted 01 December 2009 - 08:30 PM

Here's my example from Monmouth County, NJ:

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#35 Carl

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Posted 02 December 2009 - 10:34 AM

Now THAT'S a spot on Ophiomorpha burrow (once called Halymenites)!

#36 Redlichia

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Posted 21 February 2010 - 06:28 PM

Or is a type of Ophiomorpha sp.,or is a nodule of ematite mineral?
->>>>> :)<



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