Jump to content
FossilNerd

Orthoconic Nautiloid?

Recommended Posts

FossilNerd

I made a trip to my new favorite Upper Ordovician (Drakes Formation) spot today (working on a field trip report ;)). I came across a few of these cylinders, which I believe are orthoconic nautiloids. I found them in many different sizes. Some taper as I would expect from an orthocone. However, they do not have the suture lines or septa that I am used to seeing. Some have what appears to be a possible siphuncle in the center while others do not.

 

Here are a few pics of some of the more interesting ones. I can provide more if needed. Thoughts? Thanks in advance for any assistance!

 

All.JPG.022ccfbcb32ba92d25be09923ed2762f.JPG

 

 

 

 

 

This one is about 3cm in diameter and 7.5 cm length. Number 8 in first pic.

 

Cylinder1.JPG.7206ad3c2a75d978f3c6f807d82ae7e3.JPG

cylinder2.thumb.JPG.089e1d45048c7575866d354ad00a0378.JPG

cylinder5.thumb.JPG.04982ab05a029e6913d2b572d45e90de.JPG

cylinder4.JPG.039c491f7a7616346c741bb1c7a63a6a.JPG

cylinder3.JPG.ff8d4202e0dfffe9b92b158fc861c311.JPG

 

 

There are also a couple that have this twisting pattern on the outside. This one is about 5cm in diameter and 3.5 in length. Number 4 in first pic.

 

spiral2.thumb.JPG.ae3ba28e9ce5f9ba81992312dfda35d4.JPG

spiral1.JPG.d2f6d958b22733bfba7a941a180cd1d5.JPG 

 

 

Possible Siphuncle? 1 cm in diameter. Number 7.

 

small1.JPG.a1d094b52ba91058309ef4b57df01a93.JPG

 

Share this post


Link to post
Share on other sites
Manticocerasman

those are odd, since there are no chambers I would exclude orthocone, on the other hand if the area is known for big orthocones ( like Cameroceras ) you might have fragments of the siphuncle itself, although 3 cm seems very big for a siphuncle. I'm yust speculating now :) 

 

 

Share this post


Link to post
Share on other sites
Rockwood

I think the isolated siphuncle idea is good. There were some monsters around at about that time.

Share this post


Link to post
Share on other sites
FossilNerd
6 hours ago, Manticocerasman said:

those are odd, since there are no chambers I would exclude orthocone, on the other hand if the area is known for big orthocones ( like Cameroceras ) you might have fragments of the siphuncle itself, although 3 cm seems very big for a siphuncle. I'm yust speculating now :) 

 

 

 

4 hours ago, Rockwood said:

I think the isolated siphuncle idea is good. There were some monsters around at about that time.

I haven't collected here much (yet...) so I'm unsure of the types of orthocones that should be found, but according to the below USGS paper, Treptoceras cincinnatiensis should be there. It's described as being Medium-sized (up to 55 cm in length, having shell diameters up to 7.5 cm). That doesn't seem big enough to have a siphuncle that size.

 

Maybe they are something else altogether, or multiple somethings. Maybe similar to a modern tube sponge? Tube Sponge

 

 

 

Frey, Robert C. Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati arch region of Kentucky, Indiana, and Ohio / by Robert C. Frey. p. cm. — (U.S. Geological Survey professional paper; 1066-P) 

 

 

Share this post


Link to post
Share on other sites
Jeffrey P

Trace fossils? They appear similar to Ordovician ones I've seen outside of Montreal.

Share this post


Link to post
Share on other sites
FossilNerd
29 minutes ago, Jeffrey P said:

Trace fossils? They appear similar to Ordovician ones I've seen outside of Montreal.

Like an infilled burrow or the like?

Share this post


Link to post
Share on other sites
Rockwood

 

1 hour ago, FossilNerd said:

Like an infilled burrow or the like?

The geometry seems a bit too precise, and the crystals that fill one seem too complete in my opinion.

Isolated possible siphuncle fragments might not figure prominently in the listings anyway.

Share this post


Link to post
Share on other sites
FossilNerd
1 hour ago, Rockwood said:

 

The geometry seems a bit too precise, and the crystals that fill one seem too complete in my opinion.

Isolated possible siphuncle fragments might not figure prominently in the listings anyway.

I thought that as well. They seem too uniform to be a burrow, but I don’t know what other trace fossil would be cylindrical. 
 

Some are definitely filled with crystals.


22984EFA-73CB-4FA7-B946-B81BF36743AE.thumb.jpeg.c7077f4f169c0cdea59a5d2b782aa254.jpeg

 

Share this post


Link to post
Share on other sites
FossilNerd
1 hour ago, Rockwood said:

Isolated possible siphuncle fragments might not figure prominently in the listings anyway.

It would be awesome if it was a siphuncle, and Camroseras (or similarly large Orthocone) may be in the area. More research is needed on my part and it definitely gives me a starting point.

Share this post


Link to post
Share on other sites
minnbuckeye

I find many crystal filled orthocone cephs every year. I find many siphuncles every year. But I have YET to find a crystalized siphuncle. Not saying it couldn't be, BUT... 

 

 Mike

Share this post


Link to post
Share on other sites
FossilDAWG

I agree with Aulacera (which is known in the older literature as Beatricia).

 

Don

Share this post


Link to post
Share on other sites
piranha
14 hours ago, FossilNerd said:

There are also a couple that have this twisting pattern on the outside. This one is about 5cm in diameter and 3.5 in length. Number 4 in first pic.

spiral2.thumb.JPG.ae3ba28e9ce5f9ba81992312dfda35d4.JPG spiral1.JPG.d2f6d958b22733bfba7a941a180cd1d5.JPG

 

 

The twisting pattern is a morphological feature of: Aulacera undulata

 

image.thumb.png.70295a19765166ac0111f66166cba856.png

 

figure from:

 

Shimer, H.W., Shrock, R.R. 1944

Index Fossils of North America.

Massachusetts Institute of Technology Press, 846 pp. 

Share this post


Link to post
Share on other sites
Rockwood

Wow !

It does look like something a porifera would do. 

Share this post


Link to post
Share on other sites
FossilNerd

@erose @FossilDAWG @piranha

 

Thanks so much! I think you may be correct. :thumbsu:
 

Also, thanks for the link and book reference. Off I go to research! :look:
 

One more question... Is it wrong that I’m excited for it to be a sponge and not an nautiloid? :heartylaugh::P

Share this post


Link to post
Share on other sites
Rockwood
1 minute ago, FossilNerd said:

Is it wrong that I’m excited for it to be a sponge and not an nautiloid? 

_ _ _ _ no.

Share this post


Link to post
Share on other sites
Peat Burns
3 hours ago, FossilNerd said:

I’m excited for it to be a sponge and not an nautiloi

I resemble that remark!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×