Please help me ID this Cetacean Petrosal from Peace River, FL

[megchhool]

I have spent many hours on this forum, but this is the first time I am posting because this inner ear bone has me completely stumped. It is the first inner ear bone I have found, and it appears to be the periotic of a small/medium cetacean. I see strong similarities with some dolphins and pygmy sperm whale specimens also pulled from the Peace River in Arcadia, FL, but none that really match up. I am new to identifying anything beyond teeth, but I was excited to find this and would love to have a better idea of what animal it is from.

[Fossildude19]

@Boesse  @Harry Pristis  @PrehistoricFlorida  @siteseer  @caldigger

[Doctor Mud]

Gosh,

 

That is an interesting looking one.

look forward to what the experts have to say.

I was looking at many images of periotics since I also recently found one in New Zealand and I saw nothing quite like this.

[caldigger]

The shape doesn't match any that I have been used to, but it does look like part of it is broken off.

Let's hope one of the heavy hitters jumps in and takes a look.

[megchhool]

Yes, part of it has broken off of one end. But even just looking at the part that is well-preserved with all of the channels, it isn't matching up with anything I am finding from this region. I can't tell you how many hundreds of periotics I have compared it with this week in my amateur attempts to narrow down possible species 

[Plantguy]

Yep it does look different than the periotic stuff I've run into as well. I hate when they have pieces broken off but thats the game we play. Hoping Bobby or one of the others recognizes something diagnostic and can give you a family/genus ID. Very cool!

Regards, Chris  

[Boesse]

Okay so this is a land mammal petrosal/periotic! Not from a cetacean. They're even weirder looking than a dolphin earbone. They're also much, much harder to identify because mammalogists in the past have relied so much on teeth that these bones almost never 1) get removed from the skull properly and 2) get well illustrated. There is a big monograph on artiodactyl and other ungulate petrosals by Maureen O'Leary (Stony Brook) that I just went through, and I think that it could be tapir. I don't know my way around these like I do with dolphins, so it's possible it could be from something else - and I don't know what the petrosal of any edentates or a giant beaver would even look like, and this is in the size range. We have in our collect (donated by Ashby Gale of Charleston Fossil Adventures and found at Edisto Beach) a much larger version of this same morphology, so whatever this is it has a closely related larger relative (horse/tapir, maybe?).