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No, not named for the famous dive/snorkel spot in Grand Cayman where tourists can interact (usually quite safely) with swarms of Southern Stingrays but instead referring to the abundance of Dasyatis sp. teeth from the Montbrook fossil site in north-central Florida. While this site is a treasure trove of fossil material providing huge numbers of specimens of turtles as well as other creatures like alligators, gomphotheres, tapirs, peccaries, llamas, and ever an early saber-toothed cat, many taxa on the faunal list are only known from micro-fossils. In addition to valuable and scarce fossil remains providing evidence for things like snakes, lizards, frogs, salamanders as well as several species of birds, the micro-matrix is loaded with huge numbers of more common fossils.

 

A variety of tiny fish teeth and vertebrae (and lesser numbers of more delicate ribs and skull fragments) are common finds. There are a number of species of minuscule shark teeth as well--though the majority seem to be from a species of sharpnose shark (Rhizoprionodon sp.) with a few novelties tossed in to make it interesting. By far and away the most common chondrichthyan fossil at this site are from stingrays. In a report of the relative abundances of chondrichthyan specimens from this site (encompassing nearly 13,000 specimens) the vast majority (well over 9,000) are tiny Dasyatis teeth. The preservation colors at this site are quite different from the phosphatic black/gray coloration predominantly found in Florida creeks/rivers. Most are tans and light browns with a number of creamy white teeth that are so bright and clean that they look like they could have been shed yesterday. I'm presently picking through some finer material that was washed through a fine brass screen so the finds tend to be around a millimeter in size (requiring a microscope to spot on my picking plate).

 

Last night I finished a batch and was amazed at the density and diversity of color, form, and size (some really tiny juvenile teeth in there as well). I decided to take a "wallpaper" image of a spread of these tiny teeth for fun. For reference, the field of view in this image is roughly the size of a US postage stamp.

 

Cheers.

 

-Ken

 

Dasyatis.jpg

 

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  • digit changed the title to Stingray City

I like abstract images and I thought that uniformity and the diversity of these tiny teeth would make for an interesting image. Though sized to be able to use for a computer screen background wallpaper image, I think this might induce migraines if you had to stare at it all day long. :oO::s_cry::wacko:

 

 

Cheers.

 

-Ken

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That would make for a great puzzle.  Does anyone else remember puzzles?

 

Don

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thelivingdead531

That would definitely make a great and challenging puzzle!

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Hi Ken,

 

Since frogs and salamanders can't tolerate saltwater, I assume the stingray may be a freshwater form and perhaps the last of the freshwater stingrays in North America.

 

Jess

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fossilselachian
4 hours ago, FossilDAWG said:

That would make for a great puzzle.  Does anyone else remember puzzles?

 

Don

I believe one would run out of ‘adult beverages” long before finishing such a puzzle.

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4 hours ago, FossilDAWG said:

That would make for a great puzzle.  Does anyone else remember puzzles?

 

Don

 

My mom still likes puzzles and so does one of my uncles.  He and my aunt have covered a wall in a guest room with puzzles.

 

It's not a generational thing either.  My teenage niece loves puzzles so Grandma tries to have a new one ready if she's spending the night.  My baby niece likes to help too.

 

Jess

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23 hours ago, siteseer said:

Since frogs and salamanders can't tolerate saltwater, I assume the stingray may be a freshwater form and perhaps the last of the freshwater stingrays in North America.

Nope. Seems to be a mixture of environments. The site seems to have been a river system (possibly a bend that accumulated material to be fossilized). They still haven't mapped the overall extent of the site--there are fossils everywhere they dig when they expand. There are lots and lots of turtles (including what is called the 'Turtle Mortality Layer' where they are packed and stacked). Lots of gator parts and an incredible density of freshwater fish fossils (like gars). There are also fish identifiable fish teeth from fish species that are marine (Sheepshead, Pinfish, wrasse and drum species). There are several species of shark teeth (mostly sharpnose sharks, Rhizoprionodon sp.), myliobatid (Eagle Ray) tooth plates, and of course all those Dasyatis teeth (a marine stingray).

 

This may possibly have been a river delta environment which would explain the mixture of marine and freshwater species or possibly the marine fossils may be coming from an older layer cut through by the river system when the other fossils were deposited. This would be much like the Peace River producing marine (meg teeth and dugong bones) as well as freshwater (gator and turtle bits). If that is the case then the marine fossils are actually reworked and redeposited at the site. I don't think they've been able to determine that much about the taphonomy yet.

 

But the ray array displayed above is definitely marine Dasyatis and not a species of freshwater skate as is found in the Green River Formation out west.

 

 

Cheers.

 

-Ken

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On 8/7/2020 at 7:35 AM, FossilDAWG said:

That would make for a great puzzle.  Does anyone else remember puzzles?

 

Don

That was gonna be my suggestion :) lol

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On 8/8/2020 at 12:35 PM, digit said:

Nope. Seems to be a mixture of environments. The site seems to have been a river system (possibly a bend that accumulated material to be fossilized). They still haven't mapped the overall extent of the site--there are fossils everywhere they dig when they expand. There are lots and lots of turtles (including what is called the 'Turtle Mortality Layer' where they are packed and stacked). Lots of gator parts and an incredible density of freshwater fish fossils (like gars). There are also fish identifiable fish teeth from fish species that are marine (Sheepshead, Pinfish, wrasse and drum species). There are several species of shark teeth (mostly sharpnose sharks, Rhizoprionodon sp.), myliobatid (Eagle Ray) tooth plates, and of course all those Dasyatis teeth (a marine stingray).

 

This may possibly have been a river delta environment which would explain the mixture of marine and freshwater species or possibly the marine fossils may be coming from an older layer cut through by the river system when the other fossils were deposited. This would be much like the Peace River producing marine (meg teeth and dugong bones) as well as freshwater (gator and turtle bits). If that is the case then the marine fossils are actually reworked and redeposited at the site. I don't think they've been able to determine that much about the taphonomy yet.

 

But the ray array displayed above is definitely marine Dasyatis and not a species of freshwater skate as is found in the Green River Formation out west.

 

 

Cheers.

 

-Ken

 

Hi Ken,

 

The freshwater stingrays of North America descended from marine stingrays of the Late Cretaceous.  They are known from the Paleocene of New Mexico.  One of the two Green River Formation stingray genera (Heliobatis) is a dasyatid and the other one, Asterotrygon, is more closely related to bat rays. 

 

Skates belong to another order of rays which are all marine forms (tend to inhabit deeper water environments).

 

Jess

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I enjoy days when I learn something new. ;)

 

Cheers.

 

-Ken

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