You learn something every day (if you are lucky)

[digit]

After a year and a half of searching followed by 6 months of time and effort related to buying, packing, moving, unpacking, and selling, Tammy and I are finally translocated to the Gainesville, FL area and out of South Florida. Hopefully, we'll have less hurricanes to deal with and significantly less year-round yard work to tend to. I'm leaving the riding lawn mower behind and hope to do less weeding and yard work in the new house. We specifically looked for a house without a lot of grass to mow and our house has only a narrow strip adjoining our neighbor's lawn. Our neighbor's son owns a lawn and landscaping business and is nice enough to cut his dad's lawn. It would be literally 2 passes with the mower so we're working out a deal with him so I never have to cut the grass again.

The new house is on a little less than an acre but is surrounded on three sides by dense trees. The backyard slopes down to a creek that delimits the back boundary of the property. I had it on good authority that this was a fossiliferous creek and a few minutes a couple days back with a shovel and a sifting screen were sufficient to prove that assertion.

 

 

Pretty fine gravel and so the shark and ray teeth are mostly pretty small (megs may be scarce here) but as a proof of concept I can state that I now have a continuous supply of fossils from my very own yard. Not the deciding factor in choosing this property (location, the neighborhood, and the wooded low-maintenance lot were more important) but nice to be able to have friends with kids over for a fossil hunt without leaving the yard (when that becomes a reality again post-pandemic).

 

Other than to escape hurricanes and yard work, our motivation for relocating to a slightly higher latitude was to be closer to the University of Florida. We enjoy going out to the volunteer fossil digs and I've been eager to start volunteering more with the FLMNH (Florida Museum of Natural History). Due to the unusual times we find ourselves in the midst of presently, the volunteer program at the FLMNH is somewhat suspended. They can't have volunteers coming into the prep lab to work on jacketed specimens or doing the other volunteer efforts for the museum. Fortunately, I enjoy picking fossils from micro-matrix--I've processed countless 5-gallon buckets of matrix from Cookiecutter Creek, the Peace River, and other locations. I have a stacked set of sifting screens for classifying matrix and very functional lighted magnifier for looking through the more coarse material. For the finer (millimeter scale) micro-matrix my digital camera microscope and a large flat-screen TV monitor make efficient work of picking the finest material for interesting tiny treasures.

 

http://www.thefossilforum.com/index.php?/topic/95821-optimizing-my-search-technique-for-picking-fine-micro-matrix/

 

I've been waiting nearly 2 years to be able to volunteer some effort into working down the large backlog of accumulated bags of matrix from the volunteer dig sites. One of these days I'm sure I'll come across a bag of micro-matrix from one of the grid squares that I myself have dug at some time in the past.  Till then I've just gotten started looking through my first batch of washed and dried matrix from the Montbrook dig site SW of Gainesville. This is a really interesting late Miocene site with some really remarkable finds. A goodly amount of the described taxa in the faunal list for this site are represented only as micro-fossils. It is very interesting to see what is hiding in the micro-matrix as usually we only see the larger "macro" fossils that turn up while digging in the assigned grid square (ubiquitous turtle pieces, gator teeth and bones, the occasional large gomphothere bone, and other interesting species).

 

Picking through the screen washed and dried matrix (which removes the sand, clay and fine silt) turns up lots of tiny bone fragments but aslo surprising number of complete toe bones (phalanges) from turtle, gator and other species. These weight-bearing bones are often very dense and fossilize unusually well as complete specimens. There are also enough ganoid garfish scales to pave an airport runway. One of the most common millimeter-scale fossils is the extremely abundant stingray (Dasyatis) teeth which along with tiny Rhizoprionodon shark teeth make picking the finest matrix continuously interesting.

 

https://www.floridamuseum.ufl.edu/montbrook/faunal-list/

 

I'm still learning the faunal composition of this matrix (different in many ways from Cookiecutter Creek) and hope to soon find some the less common taxa like rodent teeth and some of the more unusual amphibians. I did start seeing an unusual type of fossil turning up with regularity. I had no idea what it was but a continuous supply of these tiny (just a few millimeters) cupped structures which look like microscopic canoes kept showing up in the finest size class matrix. I took a group photo of these little oddities and inquired with Richard Hulbert to see if they had been identified.

 

 

Richard thought they appeared to be part of some invertebrate and sent the specimens to Roger Portell who is in charge of the invertebrate side of the FLMNH collection. They did analysis and found them to be composed of calcium phosphate which is usually (but not always) associated with vertebrate fossils (inverts tending to use calcium carbonate more commonly for their skeletal structures). For a while they thought these might be some sort of mouth part from a shrimp or other type of crustacean but that lead didn't pan out. Finally, they managed to contact someone who was well familiar with these objects and a certain identification was made. I'd have never guessed what these were in a million years thinking initially that they sort of resembled some sort of botanical seed pod (which they clearly were not based on their composition). It turns out that these little ovoid cupped structures are from frogs and are the vomerine (upper palate) teeth located behind the maxillary teeth which are embedded in the jaw. These teeth are thought to help in grasping prey items. None of the frog's teeth are actually used for chewing as prey are swallowed whole. I don't believe frogs shed vomerine teeth the way sharks go through a continuous supply of renewable teeth so I'm guessing that frogs must have been pretty common in this fossil habitat and that these solid vomerine teeth preferentially fossilize better than the thinner and less calcified other bones of the skeleton which are not as well represented at the site.

 

 

 

Frog vomerine teeth! Who'd have thunk it? This nearly rivals the famous Merritt Island micro-matrix in which Julianna @old bones found her tree frog phalanx, thus giving it the alternative name of "frog toe micro-matrix".

 

 

Cheers.

 

-Ken

[Tidgy's Dad]

Thanks. 

Indeed I have learned something new which is great and rather fascinating. 

And congrats on your new home, here's hoping you never have to mow the grass again. 

[grandpa]

Ken, Congratulations on finishing the move to N. FL and close to FLMNH.  I know you've been looking forward to this.

 

Also congrats on a great scientific find (VFOTM?)  What an interesting discovery with some strong implications on the biota of the deposit.

 

So glad to see you are having fun!

[digit]

15 minutes ago, grandpa said:

So glad to see you are having fun!

If you are not having fun you are doing something wrong.

 

I'm happy to be able to finally start logging some hours of volunteer work for the FLMNH. Surprisingly, (or NOT!) most volunteers are not highly keen on picking through bag after bag of gravel looking for tiny micro-fossils. I enjoy the challenge so it is a way I can benefit the museum and learn a thing or two along the way.

 

Frog vomerine teeth were so out of left field that I felt I had to share that with the forum just to add a bit of surreal wonder and spread a bit of knowledge (though I don't suppose this is a topic that will prove useful on Jeopardy anytime soon).

 

 

Cheers.

 

-Ken

[FossilNerd]

Well I certainly learned something new! I had no idea frogs even had vomerine teeth.

 

Congrats on everything! The move, the awesome finds, and most importantly... the lack of grass to mow! 

[deutscheben]

Congrats on the new home and personal fossil site! Those frog teeth are absolutely fascinating.

[fossilsonwheels]

Congrats on the move and the finds !! I really enjoyed reading this and those frog pieces are awesome  

[thelivingdead531]

Everything in the post is wonderful. Congrats on the move and having your own fossil hunting grounds, literally in your backyard! I didn’t even know what vomerine teeth were, let alone that frogs had them, so thanks for sharing that! 

[siteseer]

Hi Ken,

 

It sounds like you live not far from the university.  I've spent a lot of time in the Gainesville area over the past fifteen years.  It gets a lot of rain in general but hurricanes tend to lose a lot of strength by the time they get to the area. 

 

A few years ago, I was visiting a friend southeast of Gainesville out in the country and saw some wild turkeys cross a clearing.  You might see some of those too.

 

You do have to be careful with fossil collecting in the creek.  I assume you can do it on your property and private property in general if you have permission but I heard the city recently outlawed collecting in creeks on city/county property.  You should look into that to nail down the particulars.

 

When I saw those fossils, I though they might be fish otoliths and would not have guessed frog stuff.  My second guess would have been seeds.

 

Jess

[Darbi]

@digit, how do you distinguish fossilized vomerine teeth from the modern ones? Bright and vivid yellow color strikes me rather modern but please don't mind me, I'm just learning!

[digit]

7 hours ago, siteseer said:

You do have to be careful with fossil collecting in the creek.  I assume you can do it on your property and private property in general if you have permission but I heard the city recently outlawed collecting in creeks on city/county property.  You should look into that to nail down the particulars.

Yup. They seem to be enforcing local laws prohibiting collecting in the creeks in town--I believe as the result of some people making a mess of the banks and generally ruining things for the rest of us. Because this creek is on my property I'm allowed to hunt fossils in it. Richard Hulbert has said as much and would like me to collect a diversity of chondrichthyan fossils so that we can write a paper on it.

 

7 hours ago, siteseer said:

When I saw those fossils, I though they might be fish otoliths and would not have guessed frog stuff.  My second guess would have been seeds.

 

My first instinct was seeds as well due to the shape but the calcium phosphate composition nixed that idea.

 

24 minutes ago, Darbi said:

@digit, how do you distinguish fossilized vomerine teeth from the modern ones? Bright and vivid yellow color strikes me rather modern but please don't mind me, I'm just learning!

There are no dumb questions (excepting politicians, of course ). The matrix that these frog vomerine teeth were picked from came from material about 20 feet below the surface in a formation that is late Miocene (as dated by a mixture of species including gomphotheres which predated the more modern mammoths/mastodons). If it was loose float material gathered from someplace like the Peace River then accurate dating would be more suspect.

 

 

Cheers.

 

-Ken

[Darbi]

3 minutes ago, digit said:

If it was loose float material gathered from someplace like the Peace River then accurate dating would be more suspect.

Thanks! The quote above is more what my question was about.

[digit]

Yup. I had found these in disturbed (gravel bed) float material instead of from an in-situ layer that was far below the present day ground level and in the presence of other species dating to about 5.5 Ma, then I'd be curious as to what possible modern day frogs could have vomerine teeth of this size and shape. The fossil site is primarily late Miocene with a little bit of older Eocene reworked material in there as well (it was a riverbed habitat which included some older material in the same way that the Peace River contains Plio/Pleistocene fossils with some modern bits mixed in.

 

 

Cheers.

 

-Ken

[digit]

UPDATE!!!:

 

The title of this post is "You learn something every day--if you are lucky" and Friday was a lucky day.

 

Back last July when I starting picking micro-matrix from the Montbrook site here in north-central Florida, I had started finding several of these little specimens that looked much like split popcorn kernels or something similarly seedy. I was told that these items (which I'd been referring to colloquially as "canoes") were made of calcium phosphate and thus were more likely to be vertebrate in nature as most solid parts of invertebrates (especially mollusks and crustaceans) tended to be made of calcium carbonate. It is possible to blast these specimens with a laser while imaging in a scanning-electron microscope (SEM) and doing a spectral analysis on the vaporized residue to determine chemical composition--they did indeed contain calcium phosphate.

 

Images of some of the first specimens were shopped around to various specialists to see if they rang any bells. The theory at the time was that these were these unusual structures known as "vomerine teeth" from some frog species. That working theory had puzzled me as I continued to pick more and more material. Where were the other frog bits? I've found a few potential mandibles that might be attributable to anurans (froggies) and a very conclusive pelvic bone but supplemental frog material did not seem to be hopping into my picking plate. I had a growing suspicion that this working theory was in need of some attention.

 

 

I continued to find a steady stream of these "canoes" and I sorted them into a little bead jar labeled "canoes" while I was picking. Many of these were paper thin and translucent. The edges ("gunnels") would often wear away till only the flattened base ("the bilge" to carry on the boating metaphor). Some contained more of the original structure and often contained extended material at either tip. You can see a bit of the diversity in size and form in the photo from above.

 

 

These extended tips seemed to me to make these most un-vomerinesque in form (but then I'm no expert on the dentition of frogs). It was when more complete specimens like this one with the dented convex surface and a nicely complete specimen with structure on the backside that was remarkably preserved that the mystery was solved and the true identity came to light.

 

   

 

These specimens were key to understanding how un-toothlike these objects were--though they are used as part of the feeding process. These "canoes" turned out to be the dactyl clubs of mantis shrimp:

 

 

Mantis shrimp dactyls (specialized feeding appendages) come in two types--spiky and blade-like (spearers) or hammer-like (smashers). The spearing type are used to reach out and snag prey like passing fishes with a lightning strike that impales them and pulls them back to the mantis shrimp with speed and efficiency that would be the envy of any spearfisher. The smashing type are used to stun and crush the hard protective shells of the invertebrates that form the bulk of the diet for these types. Aquarium owners have often learned that the strikes of large "smasher" mantis shrimps can pack the punch of 22 caliber rifle bullets--usually at the expense of one of the glass panes of their tanks.

 

You can easily see how the final joint of these appendages matches up very nicely with the more complete specimens. We also find quite a number of the serrated dactyls from the "thumb-splitting" spearing type of mantis shrimp so it is nice to now have both types positively identified as being present at the Montbrook site.

 

It now makes sense why these particular parts of the carapace would be made of the stronger and more durable calcium phosphate given the stresses involved in this method of subduing prey items. There is another great image in this article (linked below) from a materials science journal. Engineers are learning techniques from the structural design of this appendage that may be applicable to making tougher composite materials:

 

https://www.materialstoday.com/composites/news/smasher-shrimp-inspires-tougher-composite/

 

It's great to have stuck with this mystery and continued to hunt for better and more revealing specimens till finally all was revealed. Now that this case is solved I can focus my attention to some of those other "mystery bits" that keep turning up while picking plate after plate of micro-matrix from the Montbrook site. Frog vomerine teeth were a bizarre (but interesting) attempt at understanding these specimens but their true nature is even more astounding and fills in more gaps in our understanding of the faunal diversity of this site.

 

 

Cheers.

 

-Ken

 

[Nimravis]

Ken,

 

Great write up and finds, I really love the pictures. Congrats on your move to Gainesville, we always stop there on our way to and from Sanibel. 

[Al Dente]

Good update. Just watched a TV show on the smasher type mantis shrimp a couple days ago. I think it was on the Nat Geo or the Smithsonian channel.

[digit]

12 hours ago, Nimravis said:

Congrats on your move to Gainesville, we always stop there on our way to and from Sanibel. 

 

Let me know the next time you are passing through.

 

It is really great to be at the hub of Florida fossil activity. I'm learning new stuff at a much accelerated rate

 

 

3 hours ago, Al Dente said:

Just watched a TV show on the smasher type mantis shrimp a couple days ago. I think it was on the Nat Geo or the Smithsonian channel.

 

I've seen lots of mantis shrimp (neither shrimp nor mantis ) on dives all over the world including here in Florida. One of the largest is the Tiger Mantis Shrimp (Lysiosquillina maculata) that reaches truly terrifying lengths--40 cm (~16") and can have burrows so large it looks like you could plug them with a Coke can. It's a spearer type which well earns the nickname "thumb splitter". The spearing type tend to have elongate bi-lobed eyes (like the left one below) while the smashing type tend to have rounded eyes (like the other two). You can clearly see the white and the red dactyl clubs on these two.

 

     

 

Mantis shrimp have the most complex eyes of any creature on the planet. We may have superior vision to dogs with our 3 types of photo-receptors (red, green & blue) but mantis shrimps may have up to 16 different color receptors and can see from deep ultraviolet (UVB) all the way to far red (a range of 300-720 nm)--plus they can perceive polarized light!

 

Most that I've seen in the tropical western Atlantic (including the Florida area) are quite a bit smaller--more in line with the size of the little dactyl clubs we are finding. The tropical-Pacific mantids tend to be more colorful than the ones here at home. Here's a spearer type sitting in it's burrow and a little green smasher out searching for something to punch. (Both images taken underneath the Blue Heron Blvd bridge in the West Palm Beach area of southern Florida.)

 

  

 

 

Cheers.

 

-Ken

[Nimravis]

7 hours ago, digit said:

Let me know the next time you are passing through.

I will in May, even just to say hi. 

[LabRatKing]

Just adding, NOT learning something everyday is a choice.

 

learning something everyday is human.

 

great finds great posts!

[digit]

When I learn interesting things I like to be a conduit to share my tidbits of knowledge here.

 

 

Cheers.

 

-Ken