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More Micros From The Peace River And Cookiecutter Creek

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digit

Here's a bit of an update on this topic. I've been traveling lately to various locations around the Caribbean doing coral reef surveys. The trips have been back to back to back and I've had little time to do anything else but prepare for the following trip in the few short days between. As a result I've had my remaining Mazon Creek nodules simmering in a nice long soak in the bucket in my garage and my other buckets of Cookiecutter Creek and Peace River micro-matrix waiting patiently for some attention beside them. I've now gotten to a breather in my busy schedule where I'm home for more than a day and I've been able to indulge myself in a little fossil hunting from home. So nice to be able to hunt from the comfort of a chair. :)

I've just about finished up the micro-matrix that I was able to collect at the location on the Peace River that presented me with that fabulous Columbian Mammoth molar some months back (still eternally grateful to have friends like John to make trips like that possible). That spot contained a wealth of mega-mammal fauna (mammoth, mastodon, giant ground sloth, camel, bison, etc.) and it seems the mammalian richness extends down to the micro scale. I've been very lucky at being able to find some additional Sigmodon (Cotton Rat) molars. The find of the morning was a pair of associated molars in the original mandible (well, a portion of it anyway). The S-shaped ridges on the top of the tooth easily identify these as Sigmodon (literally "S tooth"). I really enjoy teeth in their original position in the jaw (because I find so very few in this original context). Made my morning. Again, apologies for the less than tack sharp micro-photos but I still need to invest in a better macro lens for my DSLR as the cheap digital microscope I'm using has limited focusing and depth of field capabilities.

Cheers.

-Ken

post-7713-0-41003700-1444235773_thumb.jpg post-7713-0-71993500-1444235773_thumb.jpg

post-7713-0-63206100-1444235772_thumb.jpg post-7713-0-05420600-1444235773_thumb.jpg

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digit

I think I've also found another posterior Sand Tiger Shark tooth--Carcharias sp. (taurus?)

post-7713-0-07782800-1444236266_thumb.jpg post-7713-0-44631600-1444236266_thumb.jpg

Al Dente led me to a diagnosis of the first one I found back in July (http://www.thefossilforum.com/index.php?/topic/55298-more-micros-from-the-peace-river-and-cookiecutter-creek/?p=597728) and I think this tooth, which is a little less worn, shows two side cusps better. I've also found a few more Nurse Shark teeth ( Ginglymostoma) but none nice enough to bother photographing and posting. I really need to get myself up to Gainesville and get me a heaping helping of Rattlesnake Creek micro-matrix if I'm to find a presentable specimen.

Cheers.

-Ken

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digit

Here's a bit of an update on what I've been finding in the micro-matrix I collected from the Peace River earlier this year. I was surprised when I spotted an unusual tooth in my paper plate while sorting through the fine gravel--a gator tooth! I'm used to finding gator teeth in my 1/4" mesh screen but this is the first I've found in my micro-matrix. This tooth was just under 6mm at its maximum width so it just barely managed to slip through my 1/4" screen that I used to remove the more coarse material from my micro-matrix while collecting it. This unusual find was (surprisingly) soon followed by another gator tooth of comparable size (though I doubt I could convincingly state these were associated). To round out the growing mini gator collection a truly micro size (and more conically pointed) gator tooth revealed itself on my plate. This one is only around 3mm wide (~1/8") and a little less than 6mm long (~1/4"). I'd say this safely holds the record for the smallest gator tooth I've yet recovered from the Peace.

post-7713-0-62733900-1444758542_thumb.jpg

Another unusual find turned up at about the same time--a small sawfish rostral "tooth" (actually a tooth-like dentical set into sockets along the length of the sawfish's blade-like snout). I've found a few larger examples of these before but this one is only 10mm long by 4mm wide which was easily small enough to end up in my micro-matrix.

post-7713-0-90825500-1444758541_thumb.jpg

Hope you enjoyed this bit of diversity from my micro-matrix as much as I did upon discovering them.

-Ken

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digit

I mentioned that I have been collecting quite the collection of small rodent dentary and I've got another incisor to add to the collection. Unlike the molars shown in previous posts, I don't think I'll be able to narrow teeth like this down to a genus or even family but it is still fun to find something as delicate as a rodent tooth that has survived being aggregated into a gravel bed in the Peace River. It also amuses me on some level to have found "elephant" and "mouse" teeth from the same spot in the river. Here's the latest rodentary addition to my collection--it's just 12.5 mm from tip to tip and I like the way you can see the growth lines along its length.

post-7713-0-57746800-1444771951_thumb.jpg post-7713-0-76589900-1444771070_thumb.jpg

-Ken

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digit

I love the little conical fish teeth that display the small enamel cap distinctly. This little one is only 7mm long and displays the lighter colored "arrowhead" enamel very well.

post-7713-0-03207900-1444772221_thumb.jpg

I also had a nice abundance of good quality Dasyatis? stingray teeth in this collection of micro-matrix from the Peace River. Here's a photo of one of the largest and most complete at about 4mm x 5mm in size posed with the tiniest example I've ever pulled from my micro-matrix. The little one is barely 1mm x 1.5mm in size. This comparison illustrates well the range of sizes for these little ray teeth.

post-7713-0-63413400-1444772220_thumb.jpg

-Ken

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digit

Finally, here are a couple of unusual shark teeth that I'd appreciate some feedback for.

The first is an example of a type of tooth I find on occasion. The tooth has a small slightly curved blade and an oversized dual-lobed root that gives the tooth a rather inflated teardrop profile. The overall size is about 5mm from tip to base and about 4mm across the bulk of the root. I've been trying to figure out if these teeth are just worn down examples that once possessed a wider T-shaped root of which the sides have been worn down to just the central nub or if this accurately represents the root as it was shaped when the tooth left its owner's jaw. I know that symphyseal teeth are often smaller and oddly shaped so I wonder if this could be an explanation for such a tiny tooth with more than its share of root? Willing to be schooled by any of the shark dentition experts that inhabit this forum.

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The second tooth is again a small one. From the tip to the furthest point of the root it is approximately 5.5mm. The root itself is rather curved and concave on the bottom which I've tried (but probably failed) to show in photographs from different angles. The base of the root is approximately 4mm x 6mm in overall dimensions.

post-7713-0-33484500-1444772680_thumb.jpg post-7713-0-69426900-1444772680_thumb.jpg post-7713-0-12523900-1444772681_thumb.jpg

The odd cupping of the root may best be seen in the first photograph. The second photo show the tooth from the top down and shows the very wide (almost triangular) base of the root. The blade (with chipped tip) is not unusual but the shape of the root is unlike most of the flattened roots I see on the rest of the teeth I glean from the micro-matrix. Does a tooth of this shape ring any bells to anyone? I can try photographing from other angles or with different lighting if someone thinks that will help.

Thanks for having a look.

Cheers.

-Ken

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ynot

Hey-hi Ken,

I probably should not throw in My 2 cents, but I think tooth 1 is a symphyseal and tooth 2 is an angel shark.

Tony

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digit

I don't know that I've heard of members of the family Squatinidae being found over in our area but for all I know it could be an angel shark tooth. We'll see what others say when they've had a look.

Thanks.

-Ken

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Al Dente

I agree with Tony's IDs for the last two teeth.

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digit

Well doesn't that just make my day! After dinner I did a little google image searching for "squatina teeth" (using a common genus for angel sharks). I was amazed not only to find teeth that had that same odd triangular cupped base as my specimen but also that there were references to these teeth being found in places like North Carolina. I now concur that this odd little tooth looks to be from an angel shark--I didn't even think that was possible coming out of the Peace River--I'm duly chuffed by that!

I'm also happy that my instincts to consider the first tooth a possibly symphyseal seem to have been borne out. Does a tiny tooth like this have any distinctive features that might indicate what type of shark might have held this tooth in the centerline of its jaw at one time?

I love learning new stuff. If I learn at least one new thing each day that will almost make up for all the stuff that evaporates from my consciousness on a daily basis.

Thanks for the feedback guys.

-Ken

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Al Dente

Does a tiny tooth like this have any distinctive features that might indicate what type of shark might have held this tooth in the centerline of its jaw at one time?

I suspect this is from a species of Carcharhinus. Here is a jaw from a modern Carcharhinus species. It is a good example of how many symphyseal teeth a shark can have and the variation in shape of the symphyseal teeth.

post-2301-0-59906600-1444823706_thumb.jpg

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digit

Quite informative--thanks. One of these days I do need to study the shark teeth more so I can try to deduce some of the less distinctive teeth I find. For example, I still don't think I can reliably tell a Hammerhead Shark (Sphyrna) from a Snarpnose Shark (Rhizoprionodon) or some Carcharhinus teeth. I still get confused even when using online information with photos as is found at the bottom of this page:

http://www.fossilguy.com/gallery/vert/fish-shark/sphyrna/sphyrna.htm

I really just need to get my bowl of shark teeth and dump it out on my desk and sort through them till I have some that are distinctively Sphyrna. Probably even more difficult to distinguish at micro size where they much more resemble Rhizoprionodon with their angled blade.

Cheers.

-Ken

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jcbshark

Interesting Ken, thanks. I never thought about the different shapes in those due to placement.:) Never found any posteriors that I know of in the matrix I've gone thru

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digit

They are not very common--though they should be at least twice as common as symphyseals as there are two posteriors to every middle tooth. That being said, I've gone through bucketfuls of Cookiecutter micro-matrix and I have quite a number of symphyseals but very few lateral or posterior teeth and that number has markedly increased with finding the 4 pictured above in the last couple of weeks. By sorting the micro-matrix from Cookiecutter Creek through a stack of sifters with different mesh sizes I am able to partition the matrix into different size classes. This makes the micro-matrix a little easier to go through as you can focus on items of a particular size more efficiently. I wrote about this a while back in this topic:

 

http://www.thefossilforum.com/index.php?/topic/71406-optimizing-micro-matrix-sorting/

 

In my notes, I noticed that most of the nice complete large Isistius triangulus teeth were coming from the portion of the micro-matrix that was between 1/4" and 1/8". My records also showed that the 1/8" to 1/12" size class turned up a much larger number of broken teeth (only the triangular crowns teeth that were split down the middle from the tip leaving only the left or right sides). The few whole teeth that were found in this size class tended to be much smaller anterior (front) teeth but, due to their size, there was also a higher chance of finding laterals/posteriors--though still at "needle in a haystack" probabilities. Below 1/12" I've only ever found one tiny complete tooth and mostly just tiny fragments from larger teeth.

 

This has provided some useful knowledge about the size distribution of Isistius triangulus teeth in the Cookiecutter Creek micro-matrix. I used this to concentrate some micro-matrix between 1/4" to 1/8" to bring along optimized samples as gifts to maximize the recipient's chances of finding some nice specimens with the least amount of searching.  If someone was interested in finding the posterior (or very curved lateral) teeth, then pulling out the matrix between 1/8" and 1/12" would be the place to look as this is their size class. The material finer than 1/12" contains some other fossil material (small Dasyatis, drum and other fish teeth) but rarely anything useful in terms of Isistius. I did sample down to 1/30" (slightly less than 1 mm) to pick through looking for the Holy Grail of an upper Isistius  (a few mm long but very narrow). So far, this fine material amounts to looking at mostly sand grains--quick to sort through but rather fruitless with few fossils.

 

Cheers.

 

-Ken

 

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MarcoSr
On 10/11/2017 at 1:18 PM, digit said:

They are not very common--though they should be at least twice as common as symphyseals as there are two posteriors to every middle tooth. That being said, I've gone through bucketfuls of Cookiecutter micro-matrix and I have quite a number of symphyseals but very few lateral or posterior teeth and that number has markedly increased with finding the 4 pictured above in the last couple of weeks.

 

-Ken

 

 

Ken

 

I see the same thing with the cookie cutters that I find from the Eocene of Virginia.  I have a good number of symphyseals but have only a couple of the very distal laterals and only a single posterior tooth.  I would expect to be finding more very distal lateral teeth and more posterior teeth than I am finding based upon the fact that cookie cutters lose their bottom teeth as a complete set.

 

I've also searched a good amount of finer sized Eocene matrix but haven't found an upper tooth either.  With the finer sized Eocene matrix that I search, after washing really well with water and drying, a soaking in 3% Walmart Hydrogen Peroxide will usually remove any remaining sand only leaving very small quartz pieces and the fossils.  This saves a lot of searching time by further reducing the matrix volume and makes the fossils easier to see.

 

Marco Sr.

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digit

Nice tip. I think the sand at Cookiecutter Creek is silica and so I don't know if reduction with hydrogen peroxide would be effective. I'm going to try to get out to the creek during the dry season and pick up some more very fine matrix in a misguided quest to see if I can find an upper Isistius.

 

Hoping to get out to your sons' place sometime next year to hunt the Oligocene and collect some micro-matrix for later picking.

 

 

Cheers.

 

-Ken

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MarcoSr
10 hours ago, digit said:

Nice tip. I think the sand at Cookiecutter Creek is silica and so I don't know if reduction with hydrogen peroxide would be effective. I'm going to try to get out to the creek during the dry season and pick up some more very fine matrix in a misguided quest to see if I can find an upper Isistius.

 

Hoping to get out to your sons' place sometime next year to hunt the Oligocene and collect some micro-matrix for later picking.

 

 

Cheers.

 

-Ken

 

Ken

 

Every matrix is different.  With my Eocene matrix, which is sand based, the H2O2 removes about 1/3 of the volume and only leaves quartz and fossils.  However, I can only use the H2O2 on the very fine fraction.  The larger matrix sizes have pyrite pieces that react with the H2O2 to produce an acid that discolors and etches the fossils.  I will send you a PM on the ranch.

 

Marco Sr.

 

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digit

Here's a last few goodies from the micro-matrix that I had sitting around waiting to be photographed. I pulled out the camera and set it up with the macro lens and connected it to the computer to compose some images of the tiny bits found in the micro-matrix. Here are few specimens that I thought worth the effort of photographing. First we have a nice selection of what I believe are Sand Tiger Shark (Carcharias taurus) symphyseal teeth. They are difficult to photo edge-on but these teeth are exceedingly narrow (virtually 2D) and seem to match-up to the other symphyseals I've found for this species while picking micro-matrix.

 

2017-10-27 14-55-58.jpg    2017-10-27 14-52-48.jpg

 

I find lots of stingray tail barb fragments but do not often find the terminal end so this was nice to see emerge from a pile of micro-matrix. The little shark tooth with the pathological split tip (split into two curved tips) was an unusual find as I don't come across many path teeth while searching micro-matrix.

 

2017-10-27 15-14-01.jpg

 

2017-10-27 15-20-26.jpg

 

Cheers.

 

-Ken

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MarcoSr
16 hours ago, digit said:

 

The little shark tooth with the pathological split tip (split into two curved tips) was an unusual find as I don't come across many path teeth while searching micro-matrix.

 

 

 

2017-10-27 15-20-26.jpg

 

Cheers.

 

-Ken

 

Ken

 

Split tips are one of the more noticeable shark tooth pathologies.  Even the shark species with the larger teeth like megalodons can have this pathology.

 

Below is a picture of a 5" megalodon from my younger son's collection with a split tip pathology.  This tooth has two well defined tips and they are also fully serrated. The tips also have two sets of serrations running between the two of them.  At some point my son needs to take a closeup of the tips.

 

59f4a124150d2_Mel9-16-03CarcharoclesMegalodon.thumb.JPG.756029e4301118caa677ddcfd63811ca.JPG

 

Marco Sr.

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Coco

Are you sure the 2 bigger teeth are from Carcharias taurus ? They look like lower parasymphyseal Hemipristis...

 

Coco

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digit
2 hours ago, Coco said:

Are you sure the 2 bigger teeth are from Carcharias taurus ? They look like lower parasymphyseal Hemipristis..

You know, you could be correct on that--the deflection of the tip would be a good clue. I'll have to look into some tooth sets online and do some comparisons.

 

Regarding pathological shark teeth--When I was at the GSA conference in Seattle last week, someone brought by a majorly deformed large meg tooth. It had an area along one edge near the tip where the tooth looked like it was a car that ran into a tree--all compressed and distorted. It had serrations all along this pathological section showing that it grew this way and was not the result of breakage. A colleague who is studying fossilized shark teeth (and specifically the evolution of megalodons) said that this sometimes happens when the tooth is forming but something is blocking the tooth resulting in the distortion. In species like hammerheads which feed on stingrays, a barb lodged in the jaw can cause these deformations. Possibly a larger bone likewise embedded in the jaw of a megalodon while that tooth I saw was forming caused the deformation that resembled so much a car wrapped around a tree.

 

Cheers.

 

-Ken

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MarcoSr
18 hours ago, digit said:

In species like hammerheads which feed on stingrays, a barb lodged in the jaw can cause these deformations.

-Ken

 

Ken

 

I have an extant great hammerhead shark jaw that has a stingray barb in the lower jaw.  The jaw has pathological teeth in the lower symphysis area  and a pair of crossed lower lateral teeth most likely the result of the barb injury.

 

59f5cc74590ea_Sphyrnamokarran(GreatHammerheadShark)1rayspinerightsidelowerjawLabialview.thumb.jpg.8e0f2998ffca482fbf98b49eb4020e37.jpg

 

59f5cca111dcb_Sphyrnamokarran(GreatHammerheadShark)1lowerjawsymphysisaaslingualview1.thumb.jpg.bc86df53c2bd84f1156da48849d5801e.jpg

 

59f5ccb5cc3d2_Sphyrnamokarran(GreatHammerheadShark)1lowerjawal7Ral8RLingualview.thumb.jpg.9502810eb628e5b82fec9bc1e0807a5a.jpg

 

Marco Sr.

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digit

That is a wonderful example of the cause of (at least one form of) pathology. Thanks for sharing.

 

 

Cheers.

 

-Ken

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