Another Jaw Specimen?

[PODIGGER]

Another find from the Peace River last week that I have been trying to identify and could use some help with.  When I first pulled this up out of the water I thought of some kind of broken limb bone. I then noticed the groove and socket that made it look like a piece of a jaw.  I tried searches for alligator and various land mammals and ruled out most of what I found.  The search did point me toward this being a maxilla, the upper jaw.  More searching led me to a picture of a dolphin skull that looked to support the maxilla idea but appeared a bit too small.  So, input from the group would be appreciated.

 

Measurements:

 

7 1/4" x 1 1/8" x 2 7/8"

            or

175mm x 26mm x 88mm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

My search led to this example of a Dolphin skull with what I think drives the idea that this is a maxilla.

 

 

 

 

The labeled areas that are underlined seem to correspond to the areas I have numbered on my specimen shown below

 

 

So, while I am leaning toward this being a maxilla I am wondering, if it is, could it be dolphin or something similar?

 

[Mahnmut]

Hi,

Interesting find!

Although I spent some time staring at 3d scans of different cetacean skeletons, I am far from being an expert.

I see the similarity, some points make me wonder though if all your landmarks are sound, so I dare to be proven wrong again, no offence meant:

-if your number 3 is the postorbital process, then you have not only the maxilla, but part of the frontal too, at least in Tursiops those are separated by a deep suture line.

-If number 2 is the antorbital notch, then there is no orbita to speak of. What could be an orbita in my eye extends from the 6 inch mark to the 4 1/4 in your last pic. Or its missing behind the process 3 (not postorbital in that case)

- I can not see it clearly in the pictures, but is no.2 just a concavity, or a real hole like something that had a nerve or vessel in life?

-I agree with point one probably being an alveolar groove.

-The whole thing seems rather compact compared to modern dolphin bones. Your reference is Urkudelphis chawpipacha from the oligocene of Ecuador, that pic fits much better than modern Tursiops would, I do not know what cetaceans to expect from the peace river.

 

https://commons.wikimedia.org/wiki/File:Dolphin_Skull_Bones.jpg

 

Curious to hear other opinions...

 

Best Regards,

J

 

[PODIGGER]

Mahnmut,

Thank you for your input.  #2 is clearly a hole and I believe it is something that would act as a channel for a nerve or vessel.  I do not know what I have in hand and am searching for the answer as to what this may be.  Hopefully, @Shellseeker, @Harry Pristis and some other Peace River folks will offer an opinion.

[Shellseeker]

13 hours ago, PODIGGER said:

Mahnmut,

Thank you for your input.  #2 is clearly a hole and I believe it is something that would act as a channel for a nerve or vessel.  I do not know what I have in hand and am searching for the answer as to what this may be.  Hopefully, @Shellseeker, @Harry Pristis and some other Peace River folks will offer an opinion.

Been Traveling,  This morning I get to respond to posts. I decided to answer the Smilodon Incisor post 1st, and then the Whale Tooth post, because those are far easier than identifying jaws and alveoli..  I do not have much experience with Dolphin jaws at all... I do not find them.. and I find far less maxilla than mandible...    Maxilla seems massive to me. Do you have broken edges where the fossil would have attached to the skul?

 

I think from mandible,  7 inches implies Capybara,  Tapir sized animals..  I have found lots of Tapir ...

 

This last tapir mandible is greater than 7 inches and would have an equivalent sized maxilla...

 

Jim, I can not help with Dolphin possibility,  but I can suggest other possibilities...

 

 

[PODIGGER]

Jack,

Thanks for your response. I am not wedded to the dolphin ID.  It was simply the only thing I found in my searching that seemed a possibility.  I was thinking this was too thin to be Tapir.  

I think photos 3, 4, 5 & 6 show where the bone would have attached to the skull - the wider end flaring out and curving.

 

Jim

[Bone Daddy]

Maybe I am off-base, but something about it says land critter to me. The cetacean jaw sections I have found were all quite mineralized and the later land critters have a state of preservation that looks closer to your example. I'd lean towards land, but take that with a 5-lb block of salt. 

 

[PODIGGER]

Thanks Bone Daddy.  I am sending it in to the Fl Museum Paleontology Department to see what they have to say.  Hopefully I'll get a response.

[PODIGGER]

It's been eight days since I sent the photos in to the FL Museum of Natural History and I have not received a response.  Don't know if that means they don't have any ideas or if there is a backlog of items submitted.  May be I can ask @Boesse, Dr Boessenecker, to take a look and rule out/in cetacean origin?

[Meganeura]

2 minutes ago, PODIGGER said:

It's been eight days since I sent the photos in to the FL Museum of Natural History and I have not received a response.  Don't know if that means they don't have any ideas or if there is a backlog of items submitted.  May be I can ask @Boesse, Dr Boessenecker, to take a look and rule out/in cetacean origin?

They’re veryyyyyyyyyyyy backlogged. I haven’t heard back and I sent in pics for IDs back in 2022… 

[Boesse]

This is not part of a dolphin skull. I don't know what it is exactly, but it reminds me of a terrestrial mammal pelvis that's been fragmented a bit.

[PODIGGER]

Thank you Dr. B.  I will start looking in the direction of land mammal.