Giant worm?

[TinaLu]

Hello, all. I can't wait to be enlightened all the amazing things there are to learn in this forum...

 

In the mean time, I'm hoping you all might be able to help me out with ID'ing this specimen. My father's friend found this in a lake about 30 feet from the shore. (He told me which lake and where today but I was so excited to be looking at it, I have totally forgotten. I'll be back tomorrow with that info.)  He has four segments total, found lying all together. He originally thought it was a rusted pipe. One segment appears to be an "end" as even though it is still as big around as the other pieces and doesn't taper much at all, it has what looks like well... a small opening like a mouth or anus. All pieces have the oval center running through them and what looks to be a small, round opening through one end of that oval which was maybe a nerve or vein (if it is indeed a worm or mollusk of some sort)? I've researched earthworm anatomy and it appears similar, but would maybe be something more like a giant tube worm or shipworm, I guess? The end that doesn't have the mouth/anus doesn't appear to be the actual other end as it's just a weathered version of one of the segment ends, so it's not a complete specimen. While discussing it and due to excitement, I apparently failed to get a photo of them all together, but the specimen is probably 2 feet in length and 5-6" wide. Each section is also about 5-6" long. It looks like an irregularly shaped "pipe" or rolled tune of dough, rusted in color (which I realize is from the mineral content, not the specimen coloring). Thank you for any assistance you can provide. 

[fossisle]

Baculites or straight nautiloid

 

[Douvilleiceras]

Definitely a Baculite, a Cretaceous-period ammonoid from the Family Baculitidae, Order Ammonitida. The position of the siphuncle, the cross-section matching that of a Baculite, and the complex suture rule out the possibility of a straight-shelled nautiloid. It's good sized - looks like you have a large portion of the cephalopod, great find!

 

Attached is a picture of Baculites sp. from my personal collection, found in the Pierre Shale of South Dakota. 

 

[TinaLu]

Thank you so much!

 

The suture lines on this appear to be straight vs. complex. They broke apart into relatively straight sections like a huge crinoid. 

[Plax]

your last pic shows a partial suture end at 2 o'clock

[TinaLu]

Thank you. I wasn't aware that's what that was as it is the most eroded/weathered end.

 

This was found in Lake Hattie near Laramie, Wyoming. My father's bestie will be excited to hear what he found. 

 

I truly appreciate you guys! 

[RJB]

I only opened up this post cause of 'Giant Worm'.  Got my curiousity going instantly.   But yeah, what all these guys said.  Would be interesting to see it prepped out of the rock.

 

RB

[TinaLu]

So the only fossil part is the center oval section? The way he found it as a tube thinking it was a pipe, I assumed the entire object was the fossil that had washed free from its surrounding rock and the oval in the center was the siphuncle.  But you guys are saying the oval is the shell and one circle that runs through all of the ovals is the siphuncle?? There's no chance that it was perhaps a belemnite or similar creature (where the "shell" was on the inside of the creature) which would make the surrounding "rock" part of the fossil?

 

(I'm sorry I don't understand these creatures any better, but truly appreciate the education you wonderful folks are providing.) 

[TinaLu]

Only asking because there are certain shapes that fan out from the oval, usually 4 in a certain "array" in most of the sections.  

[abyssunder]

Can we have lateral views of the specimens?

[ynot]

3 hours ago, TinaLu said:

Only asking because there are certain shapes that fan out from the oval, usually 4 in a certain "array" in most of the sections.  

Those are stress cracks in the concretion that surrounds the fossil.

[RJB]

The siphuncle is the very small circle within the big oval circle.  You can also see it in the picture I posted.

 

RB

[Douvilleiceras]

6 hours ago, TinaLu said:

So the only fossil part is the center oval section? The way he found it as a tube thinking it was a pipe, I assumed the entire object was the fossil that had washed free from its surrounding rock and the oval in the center was the siphuncle.  But you guys are saying the oval is the shell and one circle that runs through all of the ovals is the siphuncle?? There's no chance that it was perhaps a belemnite or similar creature (where the "shell" was on the inside of the creature) which would make the surrounding "rock" part of the fossil?

Only the oval cross-section is the actual fossil. The yellow rock is just layers of sediment that encased the Baculite. As for the suggestion that it could be a Belemnite, the features of your specimen do not match. Since your specimen has a siphuncle, we can readily rule out whether it's a Belemnite guard/rostrum, as this part of the belemnite only has an alveolus (the conical depression in the rostrum where the phragmocone is situated). Also, belemnite guards have growth lines and radial patterns of fibrous calcite, shown in the diagram of belemnite rostrum cross sections below (Image courtesy Hans-Joachim Engelhardt, licensed under the CC BY-SA 4.0 license, usage not endorsed by author in any way).

 

 

The other relevant part of the Belemnite is the phragmocone, or the chambered cone connected to the rostrum, briefly mentioned above. This section does have a siphuncle, which can run along the center of the phragmocone (as in many straight-shelled nautiloids) or run along the side (illustrated here). Yet, Belemnites have simple sutures, unlike your find, whose complex sutures point to an ammonoid. Also, you mention that your piece is ~2 feet long, barely getting smaller in diameter, while Belemnite phragmocones are often sharp cones, quickly coming to a point at the end of the alveolus. I'm confident that what you have is a Baculite. 

 

Diagram of rostrum with phragmocone in alveolus, from Guillaume Louis, published in 1867 (public domain):