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Carcharocles Chubutensis Sth Area?


RickCalif

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This "meg" in the pictures tied to the links....was found in an area that is supposed to be at an age of 15,5 million or middle miocene,,specifically at the east quarry on Rob's property....,Looking at this tooth....unless its some pathology going on I'd more than likely define it as chubutensis....BUT im sure it just might be a juvi meg???...I know there are some weird faults and whatnot in the area....like snake pit which has a strike that is almost vertical in relation to the nearby areas.,,,i'm just wondering if an olcese layer transects the middle miocene at the east quarry...or other areas for that matter...??? Also....maybe i'm off base with the I.D. of the tooth....if anyone knows please fill me in! I'm pretty sure it is a juvinile meg with cusps.

PICTURES:

http://www.thefossilforum.com/index.php?/gallery/image/32505-001-chub/

http://www.thefossilforum.com/index.php?/gallery/image/32506-002-chub/

http://www.thefossilforum.com/index.php?/gallery/image/32507-003-chub/

Edited by RickCalif
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I don't think it has a discrete cusp; it looks a lot more like a not-uncommon basal deformity to me.

"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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I agree. It looks like a variation of the "ripple" that can occur along a cutting edge. It is a pathology.

Maybe 20-25 years ago, Bob Ernst found the Olcese at the bottom of one of the hills near the "whale quarry." He pointed it out to me maybe 15 years ago but it was overgrown then. The Olcese is also accessible east of the access road in the dry streambed but I think that is just off the property. Exposures of the Olcese can be found elsewhere but shark teeth occur only in a shellbed right beneath a green clay and are rather uncommon. You might find 10-20 teeth in a couple of hours but you have a decent chance at a near-complete bramble shark tooth. For more on the Olcese, check out:

http://pubs.er.usgs.gov/publication/pp642

Jess

I don't think it has a discrete cusp; it looks a lot more like a not-uncommon basal deformity to me.

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Hello, i think that it's a meg too, the tooth seems to be too thick for a Chub, the base of the crown looks like a pathology. I think that it could be a lower tooth L5, but it's difficult to say because of the position of the tooth in the picture.

Edited by Sélacien34
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  • 3 years later...
On 5/1/2014 at 3:31 PM, siteseer said:

I agree. It looks like a variation of the "ripple" that can occur along a cutting edge. It is a pathology.

 

Maybe 20-25 years ago, Bob Ernst found the Olcese at the bottom of one of the hills near the "whale quarry." He pointed it out to me maybe 15 years ago but it was overgrown then. The Olcese is also accessible east of the access road in the dry streambed but I think that is just off the property. Exposures of the Olcese can be found elsewhere but shark teeth occur only in a shellbed right beneath a green clay and are rather uncommon. You might find 10-20 teeth in a couple of hours but you have a decent chance at a near-complete bramble shark tooth. For more on the Olcese, check out:

 

http://pubs.er.usgs.gov/publication/pp642

 

Jess

 

 

Hi Siteseer,

 

   Just saw this post. I would say out of the 30 plus complete meg teeth from Whale Quarry most of them have this "ripple" effect in the cusp area.  Some are more rippled then others, but most of them have it to some degree.  I'm not sure if that would fit into being a pathology, but thought I'd pass it along.  I feel there needs to be more scientific study done in regards to the STH area.  Where are the paleontologist ?  So many interesting fossils.   I sure would be interested to know what hill Bob Ernst found the Olcese in.  If you remember please PM me.  

Lisa T.

IMG_2643.JPG

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Hi Lisa,

 

How are you?

 

The ripple would be categorized as a minor pathology as it isn't "normal" for the species though it might be a character of a regional variant of the species.  I don't think it would qualify as a character to help define a subspecies, or much less, a species.  I have seen this ripple in great white teeth as well and it is considered a minor pathology in that case as well.  Maybe more members have a different opinion.

 

As I recall, just east of the Whale Quarry (and south of Bob's old fenced-in shed)  there is a rather steep drop-off which was thickly-overgrown with weeds.  If you cleared that vegetation and dug down to a green clay and then through that to a thin layer with a lot of broken shells, you would find some complete ones with shark teeth, ray teeth, occasional marine mammal bones.  Bob had a side interest in the Olcese because it offered a different mix of fossils from the STH Bonebed even though it wasn't near as productive.  The Olcese is about 17 million years old or about 1.5 million years older than the STH Bonebed.  He dug different spots with others too (like Marcel and the collector who came from Tennessee - name escapes me at the moment).  

 

A couple of days, he and I spent about two hours digging around to see what we'd find.  The Olcese is made up of different layers and the shellbed is apparently the most fossiliferous.  At first, I thought that green clay was the bottom of the Round Mountain Silt but now believe it is a layer within the Olcese.  It's been over ten years since I've dug that.  In fact, Bob passed away ten years ago last month.

 

What you notice about the sharks in the Olcese is the lack of Carcharodon hastalis and C. planus, which as you know, are common in the STH Bonebed.  The most common teeth you find are Isurus desori (aka early form of Isurus oxyrinchus), Carcharhinus, and Myliobatis.  Less common to uncommon are Squalus occidentalis (same species as in the bonebed), Hemipristis, Odontaspis (a form with long lateral cusplets like O. ferox and may be that species, some teeth being rather large), Sphyrna, Carcharocles (chubutensis or early megalodon).  You also find Echinorhinus and in larger numbers than any other Miocene site I've heard of.  I found at least one partial tooth every time I collected the layer.  Isurus retroflexus is rare.

 

The Carcharocles teeth found there are small - usually less than three inches long - but they can have a light blue color you don't see much at all n the STH Bonebed.  Most of the teeth I've seen have some bleaching.  The collector from Tennessee had a really nice light blue one that was over three inches. 

 

I can only assume you're still having fun out there.  Good luck!

 

Jess

 

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Hi Jess,

 

  We are doing well and of course still having a blast on the property.  

 

I wondered myself if the ripples were a regional variant.  Would be interesting to find out.

 

Thanks for the info on the Olcene layer and it's fossils.  We will check it out.

 

Lisa

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