Another Mammal Inner Ear Bone

[Shellseeker]

When I first started in the fossil hunting hobby, I found (on land) a mammal inner ear --- I know it is a Llama inner ear because I found an exact duplicate labeled as such on the internet -- better than nothing, I guess. http://www.thefossil...-ear-but-whose/ Includes photos

Harry Pristis was the only responder and gave me some good advice on "mammal inner ears" which likely still applies.

Lo and Behold, I have ANOTHER mammal inner ear found yesterday, approximately the same size, but it is very different from the one identified as Llama.

Before I found the first one, I had no idea what a mammal inner ear bone might look like or how they might differ -- Here is another example, so that Floridians searching for shark teeth might have an idea of what the funny shaped bone popping into their sieve might be ---

I do find strange and magical bones in my travels

[tracer]

what?

[Boesse]

It's definitely not cetacean, I'll tell you that much. Could you provide some more photos from different angles?

[Shellseeker]

Thanks Bobby,

Eliminating cetacean narrows the options. The Llama ear bone was about 3 inches but not as robust as this one at 27x28x44 mm.

I am attempting to read up on and (guess) pinpoint incus, malleus and stapes. The photos:

[cowsharks]

Is it for sure an ear bone?

Daryl.

[Shellseeker]

Is it for sure an ear bone? Daryl.

Nothing positive. Do you have another candidate? I am pretty sure that it is fossilized bone. I seem to be able to pick out the "head of the Stapes" (top of photo#2) and the round protrusion of the Malleus (center bottom of photo#4), and then in photo#5, the curious circular hole currently holding a pebble.

I am basing Inner ear somewhat on the old thread identifying a Llama Inner ear bone http://www.worthpoint.com/worthopedia/fossil-mammal-fossils-llama-inner-ear-bone

I have searched the internet for photos of mammal inner ear fossils -- There is very little.

I have found measurements of a human inner ear bones. This is a LOT bigger

[davehunt]

There's a little confusion of terms here. Yes, human INNER ear bones are very small (a millimeter or two, I think). However, pretty sure you have the petrous portion of a temporal bone. In mammals, the inner ear bones are within the petrous portion of the temporal. So, yes, an ear bone, but not just the inner ear bone(s). I'll even go so far as to guess that it is a left temporal bone (left side of the skull).

It is not out of line with the size of human temporals. However, I will say I don't think it is human (and I just finished a class on Human Osteology and my final included siding 15 different human temporal bones). My thoughts on that are that the EAM and fossa are at odd angles to each other and too distant for human.

Half the battle is getting the thing oriented correctly so you know what you're looking at. It can be very confusing to orient these lumps until you find some landmarks.

In my opinion, in the edited image I've attached, the bone is exactly upside down. The external auditory meatus (EAM) is the round-ish hole-y thing. That is the hole in the head from the outer ear. I think that depression to the right in the image is the mandibular fossa for the mandibular condyle (the connection point with the lower jaw). The fossa is forward (anterior) of the EAM, so you know which way is the front of the animal.

I think the pebble in #4 is sitting in the internal auditory meatus.

With this info, it might be helpful to see some pix with the bone in correct anatomical position and things might start to click better.

Edited December 29, 2011 by davehunt

[Shellseeker]

Dave,

First, thanks for sharing your knowledge and expertise. When I rave about TFF to other fossil hunters, I am raving about you and Bobby and Harry and other experts and moderators whose contributions make this forum THE best fossil resource. I have been moved from dummy to novice on the topic of mammal inner ears.

Next, a question -- How large is this petrous temporal bone compared to its human equivalent? basically an approximation of overall size compared to a human.

Finally the photos -- the flipped downside up photo, and then others in less pixels in case it is incorrectly flipped.

[davehunt]

The petrous portion of the temporal bone in humans is about the same size as what you have (maybe 2" or 5cm long). However, the bulby part of your bone is the auditory bulla and I believe that means it was a placental mammal, but not human (we do it differently). Surely others can verify that for me.

Edited December 29, 2011 by davehunt

[Shellseeker]

My fossil club visited FLMNH in Gainesville today. I talked to Richard Hulbert in the Paleontology Vertebrae Research Collection Lab and he positively identified this fossil as an sp. Equus Petrosal bone -- so horse. I had a fantastic day and took lots of photos.

One example is this Smilodon Fatalis partial jaw with Carnassial tooth, found in Florida -- Just FANTASTIC!!!

[Bullsnake]

Awesome find! Big kitty! Congratulations, and thanks for sharing.

[ckmerlin]

what?

[Lloyd]

Man, this is a great thread. In all my time collecting in Florida, I never got anything like this... I'm wondering if that's because, in my ignorance, I just put it back into the river not recognizing it as anything. That's one of the things I did learn over the years, and am now being constantly reminded of, if it looks in anyway "strange" put it in the save bucket.

This makes me even more anxious for my springtime trip to Florida... been a LONG time since I've been kneedeep in the Peace digging gravel.