Dugong rib possible?

[Brandy Cole]

I may be embarrassing myself here, but I can only learn if I ask. :-)

 

I found a piece in the sandy gravel of South Texas that looks similar to dugong rib examples I've seen on the forum.

 

While trying to identify it, I found an article online from October of 2020 that indicates people have found dugong fossils in Texas, but it seems like it's incredibly rare.

 

I would think it may be especially unusual to find any this far inland.  (Around Waller County, TX).

 

But I do know that so far I've found a lot of pleistocene fauna fossils here that generally seem similar to what  people find in the Peace River.  

 

So I figured I'll post it and see how off base I am.  Dugong rib?  Oddly rounded petrified wood?  Weird black rock?  It would be great to know.

 

One broken end does seem to have 'growth rings' I've seen discussed in other parts.  I'll put that picture first.  But I may need to take a picture in full sunlight to really highlight it.

 

@digit @Shellseeker

 

Thanks!

--Brandy

 

[Brandy Cole]

Whoops, looks like the pictures uploaded in a different order.

 

The fourth picture down is the one that shows the broken surface with what look like light rings around the edges.

 

Also I should note that it's heavy for its size.

[JohnJ]

Better than dugong, it looks like a tusk fragment.

 

Very cool find, Brandy!

[Brandy Cole]

Just now, JohnJ said:

Better than dugong, it looks like a tusk fragment.

Oh wow, that's exciting!  I just picked it up because of the odd shape and the resemblance to some of the ribs I'd seen.

 

What characteristics would indicate tusk?  I haven't seen many examples. I'd like to know what to look for.

[JohnJ]

Look at the "rings" closely, and you will see the diagnostic intersecting arcs of the Schreger pattern.

[Brandy Cole]

40 minutes ago, JohnJ said:

Look at the "rings" closely, and you will see the diagnostic intersecting arcs of the Schreger pattern.

 

It's hard to get good lighting and pictures without glare, but I think I see what you're talking about.

 

 

[JohnJ]

Lightly wetting it might enhance your ability to see more features.

[Shellseeker]

27 minutes ago, Brandy Cole said:

It's hard to get good lighting and pictures without glare, but I think I see what you're talking about

You already have it..  Schreger angle > 90 degrees,  so not Mammoth,  Must be Mastodon or Gomphothere. @darrow

Edited September 15, 2021 by Shellseeker

[darrow]

Schreger angle is definitely greater than 90 degrees.  That would rule out mammoth leaving mastodon as the most likely original owner of that tusk.  You’ll definitely want to consolidate with Butvar B-98 or some similar material.  Otherwise it will very likely discolor and develop cracks perhaps in only a couple months.

[Brandy Cole]

17 minutes ago, darrow said:

Schreger angle is definitely greater than 90 degrees.  That would rule out mammoth leaving mastodon as the most likely original owner of that tusk.  You’ll definitely want to consolidate with Butvar B-98 or some similar material.  Otherwise it will very likely discolor and develop cracks perhaps in only a couple months.

Thanks so much!  I'll start looking into preserving it right away.

 

Any suggestions on good sites or posts directing me on what to do would be very welcome.

[Fossil_Adult]

Woah. Thats a killer tusk man. Great find!

[Tidgy's Dad]

Nice find! 

[digit]

10 hours ago, Brandy Cole said:

I may be embarrassing myself here, but I can only learn if I ask. :-)

That was going to be the name of this forum but we (wisely) chose The Fossil Forum instead. (The URL would have been too long anyway.)

 

You've done well! If you were in Florida poking around in the Peace River your research would have turned up that dugong rib bones are common finds from the Miocene. (Dugongs are found in the Florida fossil record from about 14-7 Ma, if I remember correctly.) Given the odds, it would have been reasonable to start your ID search there and see how your specimen matches. Most folks would look for any slight resemblance and try to argue that their item is the coolest and most rare fossil they can think off--we see lots of "T-rex" teeth and "dinosaur embryos" with (il)logic like this.

 

In your example a series of well lit and exposed images were enough for our members to recognize that you had found a true gem in the rough. I started getting a "tusk" vibe when I saw the striations along the length and the concentric rings showing the Schreger Lines cinched it!

 

10 hours ago, Brandy Cole said:

What characteristics would indicate tusk?  I haven't seen many examples. I'd like to know what to look for.

I wish we had more members ask this follow-up question. It is one thing to post fossil images here and ask for an ID and another to be curious enough to ask how we know. Not only did you find an awesome fossil (I've not yet found a tusk round from the Peace--only small curved flakes) but you've also gained a bit of knowledge based on your find. My personal fossil knowledge tends to grow as I learn more about the various items I find so it is far from comprehensive but idiosyncratic to the places I've hunted and the objects I've found. It's always a great day when you can add a little to what you know about fossils.

 

 

Cheers.

 

-Ken

[Shellseeker]

11 hours ago, Brandy Cole said:

Oh wow, that's exciting!  I just picked it up because of the odd shape and the resemblance to some of the ribs I'd seen.

 

What characteristics would indicate tusk?  I haven't seen many examples. I'd like to know what to look for.

So @JohnJ got it right away,, and @digit 's excellent post has highlighted the "clues".

Let's go photo by photo.

1st Photo  -- longitudinal groves. I am extremely familiar with dugong rib.  I would venture none of them have such lines,  so it is something else.  A possibility is fossilized wood.

2nd Photo.. A hole going into one end and a very complex changing texture inside.. This is NOT fossilized wood. The hole is a root cavity that is similar in many teeth (Whale being a good example).

3rd photo  -- you can note concentric circles making the inner core at the top of the photo. This fossil "grew" larger by adding layers on the outside,  not traditional for tooth growth... (Think about your teeth  -- do they grow larger over time?)..  Concentric circles are a marker of Tusks..

4th photo. The most common fossil tusks belonged to Mammoth, Mastodon, Gomphothere and all of those were in your hunting areas. The Schreger lines differentiate and emphasize the concentric circles...

 

You just had to "read" what your excellent photos were saying!!!

 

Edited September 15, 2021 by Shellseeker

[fossilus]

Nice find! I hunt your same general area and have only found mammoth as full round tusks. I would agree with Darrow about consolidation.

I'm jealous!

[digit]

6 hours ago, Shellseeker said:

3rd photo  -- you can note concentric circles making the inner core at the top of the photo. This fossil "grew" larger by adding layers on the outside,  not traditional for tooth growth... (Think about your teeth  -- do they grow larger over time?)..  Concentric circles are a marker of Tusks..

The best way to think of hose-nose (proboscidean) tusks is to imagine the stack of conical paper cups that were found next to water coolers (is that still a thing?) in offices. Tusks are simply teeth that extend outside of the mouth. Proboscidean tusks continue to grow through the animal's lifetime by adding on new layers ("additional paper cups") to the root end. The diameter of the tusk increases steadily as the animal grows in size. This cone-in-cone structure is what is responsible for the Schreger Lines which were instrumental in the ID of this item.

 

Cheers.

 

-Ken

 

https://onlinelibrary.wiley.com/doi/10.1111/cura.12230

 

https://www.researchgate.net/figure/The-main-orientations-used-in-the-present-article-and-the-basic-structure-of-a-tusk_fig4_230798187

[garyc]

Nice tusk! Now that you found one, get ready to find more. At least that’s how it seemed to be for me 

[Brandy Cole]

Thank you, everyone!

 

@digit I really appreciate the help here and everyone's willingness to answer.  This forum has been an amazing learning tool for me.  The explanations people give when confirming or ruling out identifications has taught me more than hours of googling.

 

@JohnJ @darrow @Shellseeker

I had read about Schreger lines before in past forum posts, but I would never have thought to look for them in this piece or how to differentiate between mastodon or mammoth here.  Thanks so much!

 

@garyc

Well it should help now that I have a much better idea what to keep an eye out for.  When I saw this, I'm embarrassed to admit that I almost threw it back, considering how it looked when I found it.  I just knew it didn't really fit with what I expected from either a rock or fossil bone, so I figured it was worth a trip home with the rest for the clean up.

How it looked when I brought it home...

[garyc]

Looking at your pictures initially I would’ve put this in the petrified wood camp. It’s always a good idea just to go ahead and bring stuff home and clean it up and even post it. It’s definitely a cool find!

[Brandy Cole]

3 minutes ago, garyc said:

Looking at your pictures initially I would’ve put this in the petrified wood camp. It’s always a good idea just to go ahead and bring stuff home and clean it up and even post it. It’s definitely a cool find!

I was definitely leaning that way at the river.  But the lines, odd roundness, and difference between the top and bottom reminded me of teeth a little, so I put it in my bag.  I'm super excited I was wrong. :-)

[fossilus]

This is a chunk of mammoth tusk I found last year in the river. This piece is about 6 in in diameter.

[Brandy Cole]

On 9/19/2021 at 5:58 PM, fossilus said:

This is a chunk of mammoth tusk I found last year in the river. This piece is about 6 in in diameter.

That's amazing!  Much bigger than mine in diameter.  Something that size is probably more what I would have expected a tusk fragment to be like.

[garyc]

It took me forever to find my first piece of tusk and now I found all of these in the last couple of years. It’s interesting the different shapes and textures that they take on after tumbling down the river