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Tiny Jaw From Cretaceous


Ramo

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I was starting to organize all my stuff and came across this tiny jaw in a bag of Codell Sandstone material (Cretaceous). I probably picked it up thinking it was an encodus tooth, but today I noticed it is a jaw with little hollow tooth sockets in it. Any idea what this might be from?

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For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Phoo! That is a small jaw. Fish perhaps? Seems a little long and the teeth holes are spaces fairly far apart to me tetrapod to me.

-Dave

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Bowkill -

I think Auspex may be your new best friend. Sure looks "bird" to me!

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I was hoping bird as well, but I sent Mike Everhart these photos, and he thinks it may be from an aspidorhychid fish jaw. I looked up that fish, and saw they are gar-like and I've never found any gar-like scale, so I'm still hoping for bird.

Ramo

For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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I was hoping bird as well, but I sent Mike Everhart these photos, and he thinks it may be from an aspidorhychid fish jaw. I looked up that fish, and saw they are gar-like and I've never found any gar-like scale, so I'm still hoping for bird.

Ramo

You might send pix to Larry Martin at KU. He's done a lot with the chalk birds. I know nothing about those fish, so Mike might be right. He knows a heck of a lot more about the fauna of the chalk than me. (Still think it looks like a bird, though!)

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Phoo! That is a small jaw. Fish perhaps? Seems a little long and the teeth holes are spaces fairly far apart to me tetrapod to me.

It looks smmiler to some fish jaws that I found in the south easturn part of Iowa, But they are from a different age. And also look at the ends of the bone and if it is al flaky and stuff it is likly a bird.

-Frozen

Edited by frozen_turkey
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If its bird then the bone would be hollow, Id have to agree with fish, the striations on the bone remind me of the rostrum of a gar fish but the holes do seem strange, never seen anything like that, on a rostrum the holes usually run the other way. i will take some pics of some different fish rostrums and post them for you tomorrow.

Danny

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I'm just throwing this out there for you to compare.... but I think it also resembles a ratfish (Ischyodus) dorsal fin spine segment. But that would mean the "tooth sockets" are not natural. :) See my attached image of 2 Ischyodus spine segments. The bone texture looks similar and in your 2nd picture it almost looks like worn serrations along the edges of your specimen, but the picture isn't clear enough for me to say. But you could easily tell by examination and running your finger over the edges.

-steve

post-382-062768900 1278632065_thumb.jpg

Edited by toothpuller

---Wie Wasser schleift den Stein, wir steigen und fallen---

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I'v sent photos to Mike Everhart and he is thinking Aspidorhythnchid fish. (gar type fish) So you guys are probably going to burst my bubble with him. I have never found a gar-type scale though. I was hoping for a bird ID. I also sent photos to KU and they need to see the bone in person.

Ramo

For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Danny,

Yeah, fish jaws don't have tooth sockets as a rule. I don't think it's a fish jaw anyway because of the spacing relative to the jaw size but I don't know what else it could be either.

If its bird then the bone would be hollow, Id have to agree with fish, the striations on the bone remind me of the rostrum of a gar fish but the holes do seem strange, never seen anything like that, on a rostrum the holes usually run the other way. i will take some pics of some different fish rostrums and post them for you tomorrow.

Danny

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Bowkill,

Siteseer seems to have a good point about the spacing… It just doesn’t look right to me either, but I’m far from an expert. But that leads me back to ratfish dorsal fin spine. Did you take a close look? Here are some more images if my first was not clear enough.

Are these features (see image) definitely not the remnant bumps of serrations/tubercules like those of a Chimaeroid dorsal fin spine? They look like little bumps to me, similar to the ones in my first image, but I can't tell for sure from your picture. They could be nothing at all, just a digital artifact. Please overrule me if I’m just seeing things since you have the best view :)

The new image is from an Eocene Chimaeroid species from the Antarctic, but Cretaceous specimens are basically the same. My specimens are 2 late Cretaceous Ischyodus dorsal fin spine segments on top of a pile of sharks teeth among other things. I have noticed that the tubercules on these are often worn down to just bumps more than idealized sharp jagged serrations like in the pictured Eocene specimen.

If it does feel like bumps or tubercules on the edge of your specimen, then I would say the holes may be not natural and just a red herring here. But I can’t tell anything definitively from your pictures. Rule me out so I don’t have to waste any more time if that’s the case please. I just think that there is a striking resemblance minus those tooth sockets of course...

-steve

post-382-026362100 1278675038_thumb.jpg

post-382-046838900 1278675065_thumb.jpg

post-382-020678100 1278675054_thumb.jpg

Edited by toothpuller

---Wie Wasser schleift den Stein, wir steigen und fallen---

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Danny,

Yeah, fish jaws don't have tooth sockets as a rule. I don't think it's a fish jaw anyway because of the spacing relative to the jaw size but I don't know what else it could be either.

Hi Siteseer,

ive attached a pic of fish and fish jaw with sockets, interestingly the broken tooth appears very simular to the broken teeth/sockets on the specimen in question. looks like the teeth may have snapped off the specimen. I still think its some type of gar rostrum although very unusual.

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post-2534-050031600 1278677755_thumb.jpg

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I think Steve(toothpuller) is on the right track. The "sockets" may not be much more than 'pin-hole' sized spots with different mineralization or leaching. Some of those can be seen on his reference photo. Here is a brighter version of Ramo's photo:

post-420-040796100 1278683609_thumb.jpg

The human mind has the ability to believe anything is true.  -  JJ

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We can probably rule out bird, So its between a dorsal spine and rostra, I think both could be possible.

OK heres the fish rostra ( noses )

The first three are Cylindracanthus rectus,

The next four Aglyptorynchus venablesi,

And the last one is Hemirhabdorynchus elliotti.

All the species have two rows of very small rasping teeth.

could it be possible that the specimen in question is a variation with proper teeth :o

Danny

post-2534-098132200 1278683993_thumb.jpg

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I can definately see what you guys mean it is very simular, its just those holes :wacko:

would a dorsal spine perhaps have teeth/barbs that would look like this if broken ? , that might then explain it.

Danny

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Here is another photo. I guess I'm going to have to go with the fish ID. Besides the two tooth sockets, there is a third tooth that is just a mineralized tooth core that is hard to see. It is an equal distance as the other two.

Ramo

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post-40-026104600 1278689709_thumb.jpg

For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Bowkill,

Siteseer seems to have a good point about the spacing… It just doesn't look right to me either, but I'm far from an expert. But that leads me back to ratfish dorsal fin spine. Did you take a close look? Here are some more images if my first was not clear enough.

Are these features (see image) definitely not the remnant bumps of serrations/tubercules like those of a Chimaeroid dorsal fin spine? They look like little bumps to me, similar to the ones in my first image, but I can't tell for sure from your picture. They could be nothing at all, just a digital artifact. Please overrule me if I'm just seeing things since you have the best view :)

The new image is from an Eocene Chimaeroid species from the Antarctic, but Cretaceous specimens are basically the same. My specimens are 2 late Cretaceous Ischyodus dorsal fin spine segments on top of a pile of sharks teeth among other things. I have noticed that the tubercules on these are often worn down to just bumps more than idealized sharp jagged serrations like in the pictured Eocene specimen.

If it does feel like bumps or tubercules on the edge of your specimen, then I would say the holes may be not natural and just a red herring here. But I can't tell anything definitively from your pictures. Rule me out so I don't have to waste any more time if that's the case please. I just think that there is a striking resemblance minus those tooth sockets of course...

-steve

post-382-026362100 1278675038_thumb.jpg

post-382-046838900 1278675065_thumb.jpg

post-382-020678100 1278675054_thumb.jpg

Something I am a little confused about. Are those actually teeth on the spine

in the illustration?

Welcome to the forum!

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Ramo, I see it now. It looks like a third tooth socket or partial tooth protruding and that would, of course, rule out my guess from way out in left field :) Dang, I thought I might have nailed this one like Lebron pounding the stake through the heart of all of Cleveland! Clearer pictures would have helped from the start, but I have had the same problems in the past of photographing small indeterminate fossils. Sorry for the tangent.

-steve

Here is another photo. I guess I'm going to have to go with the fish ID. Besides the two tooth sockets, there is a third tooth that is just a mineralized tooth core that is hard to see. It is an equal distance as the other two.

Ramo

Edited by toothpuller

---Wie Wasser schleift den Stein, wir steigen und fallen---

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Roz,

Along with sawfish "rostral teeth" and stingray spines, its a modified dermal denticle used in defense by chimaeras. They look similar and are similarly composed to teeth because they both developed from the same primitive structure.

-steve

Something I am a little confused about. Are those actually teeth on the spine

in the illustration?

---Wie Wasser schleift den Stein, wir steigen und fallen---

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Roz,

Along with sawfish "rostral teeth" and stingray spines, its a modified dermal denticle used in defense by chimaeras. They look similar and are similarly composed to teeth because they both developed from the same primitive structure.

-steve

Ok, that clears it up then and thanks, Steve..

Welcome to the forum!

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Y'all seem to have gotten 'round to the idea that it isn't bird (Icthyornis had teeth set in grooves, and Hesperornis teeth were much closer together), but we can still be friends :)

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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Y'all seem to have gotten 'round to the idea that it isn't bird (Icthyornis had teeth set in grooves, and Hesperornis teeth were much closer together), but we can still be friends :)

Hi Auspex,

Are you just saying that because we ruled out bird :P

Or do you actually think there is a possibility of it being bird ? :D

Danny

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Hi Auspex,

Are you just saying that because we ruled out bird :P

Or do you actually think there is a possibility of it being bird ? :D

Danny

Safe to rule out bird :(

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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