Fish Brains Or ?

[Pool Man]

Hello all.I'd like to get some opinions on this article I recently found online. I find these fossils fairly often. I have seen them being sold at the Venice shark fest as Fossil brains. I believe they are brain endocasts. I have found enough other fish part casts, that it seems very reasonable.

http://www.lakeneosho.org/Fossil/index.html

Here's a fairly worn one I found recently

Thanks for looking!

Dan

[PaleoRon]

"specimens states that they are "Sea Brains", representing "fish ballast organs"

The last time I checked brains are not composed of bone. There are several fish bones of odd shape that are collectively called "tully" or "tilly" bones. They are described as being fish "ballast" bones, and seem to be boney growths from within a fish. I have not seen a complete fish skeleton that has these bones attached, but some of them look like they might be associated with fins and others seem to look like cranial elements. The operative words here are "look like" and these forms may be something altogether different.

Your specimen may be a fish neurocranium but I have no idea what species. If you have access to the Smithsonian's Lee Creek volume 3 you should check out the various photos in the boney fish section. If you don't have access to a hard copy you can find it online here:

http://www.sil.si.edu/smithsoniancontribut...ename=SCtP-0090

I hope this helps.

[mommabetts]

Interesting

[tracer]

i'd try to get a neurocranium and look at it and see if the internal cavity shape of it is similar to the cast. but even if that's what it is, it's more of a "skull" cavity cast than a brain cast. for consistency's sake, let's just call it a fish "prong".

(um, that last comment there should be hilarious to anybody who's able to draw analogies between two unrelated threads weeks apart, but for the others out there who are normal, it coulda been tedious. i either accept the applause or pull my cap down over my eyes in shame, or both, but appear insincere.)

[PaleoRon]

I have had similar specimens in the past including broken ones. The ones that I had were actual laminated bone and were solid all the way through. From the pics I can't tell if this specimen is actual bone or hardened sediment.

Page 174 of the text shows a similar structure.

http://www.sil.si.edu/smithsoniancontribut...o/SCtP-0090.pdf

[Auspex]

...I believe they are brain endocasts. I have found enough other fish part casts, that it seems very reasonable.

The one you're holding does not look like what I call Tilly bones, in that it seems more symmetrical. Tillys look (to me) like swolen bones.

[Pool Man]

Thanks everyone. I agree with tracer that it would be a skull cavity mold not a brain. They do not have any internal pore structure. The broken ones i've seen have a very smooth dense composition

Great PDF Ron! Thanks! The examples on 174 Letter H and I. Thats what I'm finding.

Dan

[PaleoRon]

Thanks everyone. I agree with tracer that it would be a skull cavity mold not a brain. They do not have any internal pore structure. The broken ones i've seen have a very smooth dense composition

Great PDF Ron! Thanks! The examples on 174 Letter H and I. Thats what I'm finding.

Dan

They come in several shapes and sizes and run from very fragile to very dense. Most of the pieces I have found were from the top of the skull and the rear. Sorry I don't have more reference photos.