Large Shark Teeth

[Shellseeker]

Many of you know that I have searched (almost exclusively) the Peace River for the last 5 years with some excellent results. I often go with other fossil seekers who have decades of experience with Peace River fossils.

10 days ago I found a 1.75 inch shark tooth which seemed to be Megalodon, but as you can see from the photos, it has a little something extra.

I have found Giant Thresher (1), Makos (many), Megs (lots), Hemis, and Sand Tigers in the 1.5 inch and above range. What other large shark teeth have forum members found in the Peace River ?

What are the possible identifications for this tooth?

You can click on the 2nd photo (twice) to get a better view.

[Gizmo]

Carcharocles chubutensis - http://en.wikipedia.org/wiki/Carcharocles_chubutensis or

http://www.phatfossils.com/species.php?species=Carcharocles%20Chubutensis

[Shellseeker]

Carcharocles chubutensis

I have no doubts about your ID. On the Wikipedia site,

..Although the teeth of C. chubutensis are morphologically similar to teeth of C. megalodon,[2] they are comparatively slender with curved crown, and with presence of lateral heels feebly serrated.

but there is no cusps on their example photo.

The 2nd link identifies some Chubs with cusps and others without. How do you recognize a Chub?

[RickNC]

Chub

[cowsharks]

Definitely chubutensis or Angustidens depending on the age of the material in the Peace.

[Shellseeker]

Definitely chubutensis or Angustidens depending on the age of the material in the Peace.

Generally, Peace River is dated back to early Pliocene -28 mya. I have never heard of anyone finding either a RIC or an ANGY in the Peace River. Part of my reasoning in this question is to understand how far back the Chubs, RICs, and ANGYs go.

[Harry Pristis]

If you consider C. megalodon a morphospecies, then this tooth is C. chubutensis.

If you consider C. megalodon a chronospecies, then this tooth is C. megalodon.

But, it can't be both.

See the discussion on page 86 of MEGALODON Hunting the Hunter by Mark Renz (2002).

I think that the lateral cusps of this tooth are a holdover juvenile condition, OR, the cusps represent an atavism.

Edited April 15, 2013 by Harry Pristis

[siteseer]

Shellseeker,

I agree with Harry. I have seen a couple of Sharktooth Hill (Middle Miocene) and Bone Valley teeth (Late Miocene-Early Pliocene) with weak cusplets like that. By the Middle Miocene the vast majority of teeth lack cusplets and even the ones that have cusplets from and after that time should be considered megalodon.

Jess

Harry said:
See the discussion on page 86 of MEGALODON Hunting the Hunter by Mark Renz.

I think that the lateral cusps of this tooth are a holdover juvenile condition, OR, the cusps represent an atavisism.

Edited April 14, 2013 by siteseer

[DeloiVarden]

Early juvenile meg regardless of what fancy name gets put on it. Great find.

[Shellseeker]

See the discussion on page 86 of MEGALODON Hunting the Hunter by Mark Renz.

Thanks , Harry. In the version I have, discussion of juvenile Megs occurs on pg 88, including this quote:

"Throughout the Miocene young Megs had cusps, but by the Pliocene they had lost them".

As DeloiVarden implies, I am thrilled that I have something different -- A large Meg like tooth from the Peace River that has lateral cusps. I always ask questions based on finds. Do the cusps on this tooth imply a Miocene (23.03 to 5.332 million years ago) versus Pliocene (5.332 million to 2.588 million years) age for this tooth. I realize nothing is certain, but Miocene material (3-toed, Rhino, etc) seems exciting based on rarity.

Rarity is a topic I would like input on --- As I indicated in my original post, none of my normal Peace River fossil hunting buddies have found juvenile Megs with lateral cusps.

[siteseer]

No, because it's possible for a Pliocene meg tooth to show lateral cusplets for the same reason. Having lateral cusplets remained in the genes of the species millions of years after it was basic tooth character. Occasionally, the gene for cusplets, which had been "switched off" would switch on randomly and an individual would have teeth with cusplets. You wouldn't call it a pathology but just a rare expression of an ancestral trait.

Yeah, it's very rare to see a Bone Valley meg with cusplets - probably just as rare for the Peace River.

Shellseeker said:

As DeloiVarden implies, I am thrilled that I have something different -- A large Meg like tooth from the Peace River that has lateral cusps. I always ask questions based on finds. Do the cusps on this tooth imply a Miocene (23.03 to 5.332 million years ago) versus Pliocene (5.332 million to 2.588 million years) age for this tooth. I realize nothing is certain, but Miocene material (3-toed, Rhino, etc) seems exciting based on rarity.

Rarity is a topic I would like input on --- As I indicated in my original post, none of my normal Peace River fossil hunting buddies have found juvenile Megs with lateral cusps.

[Auspex]

"Re-expressive" genes are one reason why life is so resilient; continuously pushing the envelope is not a job for new mutations alone.

[jcbshark]

Nice find regardless what you call it.lol.I know a guy who found one at a site in sarasota with cusps on it but its the only other one I've seen in the immediate area in 13 years hunting.

[Shellseeker]

Nice find regardless what you call it.lol.I know a guy who found one at a site in sarasota with cusps on it but its the only other one I've seen in the immediate area in 13 years hunting.

Exactly -- I have checked with 20-25 fossil hunters who have some experience with the Peace River -- None of them has found a Meg with cusps. This one is rare and I am thankful to have found it. It has its own riker box

[Auspex]

It deserves a Riker with a solid gold frame!