What are the chances I found a full jaw

[Maxsg]

Hi so I have been hunting my favorite spot recently, and ever since I first came to this spot I have noticed a good amount of sand tiger teeth popping up, but only in this 10 foot radius. Is it possible that all of these teeth are from the same shark. They all range in similar size and I have only ever found them in this one spot. for every nice one i have pictured. I found 10 more broken ones just missing the roots. 

 

[jcbshark]

In my experience anything is possible but highly unlikely. Unless you're digging stuff out of the original formation most stuff found in rivers and streams are redeposited and are a jumble of species and time frames.The only way to know if they are the same animal is if it died there and you uncover an associated set which seems to happen more in mines where the water doesn't have a chance to scatter material 

[digit]

Yup--like Jeff said.

 

Sometimes, the river just accumulates similar size material into a gravel deposit. The general rule (for which there are always exceptions) is that larger gravel means larger fossil--finer gravel tends to have smaller fossils. I tell beginners that fossils don't know that they are special so they just hang out with other rocks of about the same size. Seriously though, different size classes of material will drop out of transport along the river's course at different locations so it is not uncommon to find larger numbers of similar size fossils in a small area. I have one area that I've returned to often in the Peace River that has very chunky gravel. I like this spot because there tend to be larger fossils found there--though not with the frequency of smaller items like the tiny teeth. One small area in the course of one day turned up over two dozen cetacean ear bones (tympanic bullae). These were obviously not all from one individual--if it were, it would be impossible to have snuck up on this whale. The items were all just about the same size and shape and the river seems to do weird and mindblowing things when depositing fossils.

 

In most cases the shark teeth we find are not the last the set the shark ever possessed. I've heard the number quoted that a long-lived shark can easily go through 30,000-40,000 teeth in its lifetime. At any one time a shark may have on the order of 50 working teeth with possibly 200-300 teeth in various stages of development. That means they may "turn over" their teeth 100 or more times in their lifetime meaning that you probably stand less than a 1% chance that a tooth was in place when the shark died. If you do find hollow shark tooth crowns with no root and no internal dentin, you likely have an incompletely developed tooth that was still developing when the shark died. Shark teeth develop "backward" from what I naively assumed (before learning better here on the forum). They complete the enamel cap, then fill it in with dentin, and the last step is completing the root. I've found a few of these hollow teeth and I usually save them as they do tell an interesting story.

 

There is no way of knowing if the great cache of Sand Tiger teeth you are turning up at your new favorite spot are, in fact, from the same individual but the odds are long. As Jeff mentioned, about the only way of positively identifying an associated set of teeth to one individual is to dig them up in the formation (in situ) and even then they have to be found closely together (hopefully oriented so as to tell the individual tooth positions). These types of finds are very rare and exceptional when they are found. Our current Member Of The Month, @Ramo discovered a fascinating Cretaceous age shark tooth set that was rare enough to generate a scientific paper about its discovery.

 

 

Finding larger items like multiple mammoth teeth of the same size in a particular area tend to have a higher chance of association because the animal has fewer teeth (only 4 functional teeth at any one time) and you can imagine a skull washing out of a river bank during the rainy season and depositing multiple associated teeth nearby in the same gravel bed. I thought two bison molars (the first two I ever found) were associated as they were found within minutes of each other in the same hole I was digging in the river bottom. I showed them to Dr. Richard Hulbert some years back and he confirmed that they were bison. When I said that I suspected they were associated due to their rarity and the fact that they were literally right next to each other in the river bed, Dr. Hulbert taught me an important (and humbling) lesson. He showed me that one of the molars was significantly longer than the other indicating that one animal was much younger than the other when they died--resulting in differing amounts of wear to these teeth. The clincher, that headed off any rebuttals to hearing this new information, was the the fact that they were also the very same tooth position!

 

It looks like you've got a great site that is producing some nice teeth--Sand Tiger teeth are less common than most other species in the Peace River (with local pockets where they are significantly more abundant). I'd keep going back to this spot whenever you get the chance and dig it till the gravel runs out.

 

Cheers.

 

-Ken

 

[Brett Breakin' Rocks]

1 hour ago, digit said:

It looks like you've got a great site that is producing some nice teeth

I don't know about the rest of you ... but I think this Ken fellow is on to something.  Keep your ears open and you're gonna learn many things ..... 

 

[Maxsg]

Thank you so much for these responses. They have been really helpful I appreciate it.

[digit]

24 minutes ago, Brett Breakin' Rocks said:

I don't know about the rest of you ... but I think this Ken fellow is on to something.  Keep your ears open and you're gonna learn many things ..... 

 

Don't make me blush now.

 

The big trick is staying awake till the end of my (verbose) postings. I may not know much when when I think I've learned something, I do like passing it on to others.

 

I think the last sentence above could well be the tag line for this forum. If you're not careful, you just might learn something.

 

 

Cheers.

 

-Ken

[Mark Kmiecik]

The chances that all of the shark teeth from any given species in one area being from one individual are exactly zero, because even if they are you can't prove it. Since there is no way of knowing if they are, there is no way they can be, otherwise we would know. This is the most circular argument against a single individual I can think of at the moment. However, if given enough time . . . . 

 

I hope that confuses your question.

[Fossildude19]

3 minutes ago, Mark Kmiecik said:

The chances that all of the shark teeth from any given species in one area being from one individual are exactly zero, because even if they are you can't prove it. Since there is no way of knowing if they are, there is no way they can be, otherwise we would know. This is the most circular argument against a single individual I can think of at the moment. However, if given enough time . . . . 

 

I hope that confuses your question.

Au contraire, mon frère! 

 

Every once in a while, you get something like this being found.   

 

 

So, some chance, but highly unlikely.   

 

 

[Mark Kmiecik]

47 minutes ago, Fossildude19 said:

Au contraire, mon frère! 

Every once in a while, you get something like this being found.   

So, some chance, but highly unlikely.   

How would you prove that these are all from the same individual?

[Auspex]

The whole shark was found (the picture above includes the jaws, though you can't see it 'til cleaned up).

From the linked article:

"What the Gibsons unearthed were the remains of a 15-million-year-old snaggletooth shark, which paleontologists say is more complete than any other fossil of its kind in the world."

[Kane]

 

 

Or, expressed in this way:

 

P = 1/n where n [ 0,...,1]

[Fossildude19]

44 minutes ago, Mark Kmiecik said:

How would you prove that these are all from the same individual?

As Auspex has stated, the linked article states that the find was the most complete ever found. 

As long as they were all snaggletooth teeth, should be from the same individual. 

Just showing that blanket statements often have exceptions to the rule.  

[Coco]

Hi,

 

On the pic we can see different colours in teeth, it means that the minerals of the sediment in which they fossilized aren't the same... IMO.

 

Coco

[Carl]

16 hours ago, Fossildude19 said:

As Auspex has stated, the linked article states that the find was the most complete ever found. 

As long as they were all snaggletooth teeth, should be from the same individual. 

Just showing that blanket statements often have exceptions to the rule.  

Never say never when dealing with the fossil record