Something's fishy at the FLMNH

[digit]

Anybody who has read my recent posts already knows that Tammy and I moved from South Florida to Gainesville so that we could volunteer more with the paleontology department of the Florida Museum of Natural History (FLMNH). Moving out of hurricane prone South Florida and downsizing to a more manageable size house with less yardwork were additional considerations.

 

I've been picking through micro-matrix from the Montbrook site where we often volunteer to dig in the field. It's a late Miocene site which looks to have been a river system much like the modern day Peace River. The site primarily contains freshwater fossils (fishes, turtles, gators, etc.) and some mammalian land animals (gomphotheres, rhinos, tapir, peccary, horse as well as some interesting little critters like pygmy mice, squirrels, rabbits, etc.) but, like the Peace River, contains some marine specimens like shark and ray teeth that are likely reworked from older deposits in the banks. The marine specimens are often in very good condition indicating that they have not traveled far from the banks from which they eroded.

 

For a couple of months I've been picking Montbrook micro-matrix from home. I have a camera-microscope setup that allows me to pick the very fine brass-screen micro-matrix very efficiently--viewing the active area on my picking plate in a large flat-screen monitor which is easy on the eyes and easy on the neck muscles. Because I had this setup at home (which I've used to pick Cookiecutter Creek micro-matrix for the last couple of years) I was able to volunteer my time and efforts working for the FLMNH while the new vertebrate paleontology warehouse was closed to volunteers. Recently, with the new school year starting, the VP warehouse was now open to volunteers. The large building has a very low occupancy rate during the pandemic and the very few volunteers, students or staff are spread out throughout the building and masks are worn at all times inside the building.

 

I've been able to diversity my volunteering expanding on simply picking micro-matrix from home and adding some additional helpful tasks in the VP warehouse. One of the tasks that they need volunteers to help with is sorting through the chunkier end of the collected matrix. The museum collects matrix from the Montbrook site in several ways. They have found that certain layers within the dig site have a more coarse gravel which likely corresponds to stormy periods with an increased flow rate that carries and deposits heavier particles. The very fine sandy/silty layers are thought to be deposited during slower flow rates of the river. These more grainy layers have proven to be more productive for micro-fossils and so when we are volunteer digging at the site we are instructed to collect the coarse layers and pour them into sandbags. These sandbags eventually get processed by wet washing and sifting the matrix through a series of screens with varying mesh sizes. Usually, it is the "window screen" micro-matrix or the even finer "brass screen" matrix (which I've dubbed "nano-matrix") that I end up picking. In a similar manner to how I collect micro-matrix using a 1/4" screen to hold back the larger chunks, they also separate out the coarse bits with a 1/4" mesh and this > 1/4" "extra chunky" matrix has to be picked through as well. The other source of matrix comes from jacketed specimens. As the specimens are prepped out of their jackets the matrix that is removed is also washed and separated into various size classes. These samples are usually much smaller than the amount of material gleaned from full sandbags of collected grainy layers.

 

I just returned from the warehouse a little while ago and decided to write up a report on today's activities. My workspace was out in the area where some of the larger fossils are stored on open racks. You may see in the background some interesting specimens of mastodon skulls which make a splendid background to work by. The > 1/4" extra chunky matrix comes over from the main museum building (Dickinson Hall) on the university campus where the screen-washing station is located. Today there was a couple of big plastic bins with a number of sample bags of chunky goodness to pick through.

 

   

 

I work through the bag by pouring out a little at a time into one of the larger cardboard containers that they use to store fossils in the drawers of the cabinets. My task--somewhat mundane but nevertheless important--is to separate fossil from non-fossil, bone bits from matrix. Any complete (or mostly so for the rarer) specimens get put into a "choice" items container while the broken bits go into a "fossil scraps" container. Sometimes a relatively complete bone with a fresh break might mate up with the matching fragment after a bit of searching through this scraps bin. When a match is made the pieces are glued back into a whole specimen and promoted to the "choice" bin--always fun when you can match puzzle pieces and make another catalogable specimen for the collection. Here's the resulting classification of the chunky bits of a "sandbag" sample. The choice bits go into a smaller bag with the collection label and that is sealed within a larger bag with the scraps from this batch. Someone with more experience will review the fossils tossing out any common fossils that are not choice enough to be cataloged or matching up fragments from the scraps to salvage a specimen from the scrap heap. You can see that the bulk of most samples are the non-fossil matrix bits that are discarded.

 

 

   

 

 

While picking through a batch that was collected back in April 2019 I spotted something that interrupted my picking and brought a smile to my face. It was a partial Notorynchus (Sevengill Shark) tooth. I have never found one of these "in the wild". They are vanishingly rare down in South Florida (Peace River) and I've only seen 1 or 2 that have some from the southern peninsula. Apparently, they are a bit more common in central (Orlando) Florida and further north for some reason. I was volunteering at the Montbrook site a couple years back when someone pulled a beautiful complete lower tooth from the grid square in which she was digging. This is the only time I've even been able to hold such a unique shark tooth before just recently. Last week I was picking samples of the > 1/4" matrix when I spotted a partial lower tooth only missing the last couple of cusps. I didn't bring my camera to the warehouse that day but I no longer make that mistake. Spotting another partial Notorynchus today was a really enjoyable find (even though it was in poorer shape than my last find of this type).

 

 

I continued to pick through various sample bags of matrix sorting fossil from non-fossil and finding mostly the usual items I've learned to expect from this site. Occasionally, I'd pull a complete specimen and since Richard Hulbert is also in the warehouse I can quickly learn about the species and anatomical location of the novel bone I've found. It's a great way to accrete fossil knowledge one bit at a time. A great teachable moment came not long after when I spotted a (somewhat worn) vertebra that was unusual as it was horizontally oval on one face and vertically oval on the opposing side. Richard quickly recognized this as one of the verts located very near the skull on a species of fish known as Snook (Centropomus sp.). Snooks are a marine species but they are known to venture well into brackish or even freshwater environments. I've seen Snook while hunting fossil in the Peace River (many miles upstream). Richard was able to pull a more complete specimen (also recovered from the Montbrook site) for me to compare my find to and it was easy to see that they matched. Another nugget of fossil information lodged its way into my memory--but for how long?

 

  

 

  

 

Not too long after I spotted a curiosity that I've seen before. It's an interesting shark tooth with a pair of side cusps on either side of the primary cusp (when these fragile bits are not broken off). I've spotted one of these before picking Cookiecutter Creek micro-matrix and wondered at the ID of this novelty. Some tentative identifications have been posited but the true identity of this cuspy little tooth remains elusive for the moment. It is assumed that this is an older tooth--possibly Eocene in age--that is being reworked into this Miocene site. Hopefully, this little mystery will be solved before long and I'll have a good name to apply to these when they turn up (few and far between).

 

  

 

My fun and interesting finds for the day had not completed as the most spectacular was yet to show up. A little over two hours into my task I spotted another novelty sitting among the gravel I was searching--and this time it was complete! A really pretty upper Notorynchus tooth decided to brighten my day and make me question the rarity of this species at the Montbrook site. This was now 3 specimens from this species in only a couple of days picking through this chunky matrix. I've learned that rare fossils can sometimes defy the odds and turn up in clusters with no rational explanation--and then not be seen again for months. I hope I have not seen the last of these as they are such unusual and distinctive shark teeth to find.

 

  

 

The particular batch that this curious little shark tooth came from also produced a nice gator osteoderm and tooth, the Snook vert, a few random shark teeth and myliobatid ray plates, a few fish verts and some neural carapace bones--one each from a softshell (Apalone sp.) and slider (Trachemys sp.) turtle. Before I left I had processed 2 large batches of (sandbag) matrix and 7 smaller bags mostly from jacketed specimens. It was a good day "at work" with some nice rarities as well as some great learning opportunities--like I now can recognize the lateral processes of sacral turtle vertebrae.

 

  

 

Cheers.

 

-Ken

 

[old bones]

Nice finds in those bigger chunks, Ken! Love the Notorynchus.

[sixgill pete]

Ken, the complete Notorhynchus is a beauty. It is amazing how the coloration and look of those Montbrook teeth is so similar to teeth from the Pungo River Fm. at Lee Creek.

[Fossildude19]

Great report, as always, Ken.  

 

[RuMert]

Great technique and nice finds! I like how everything is accurate and thought out - from bags and picking onscreen to quality photos

[digit]

Went back to the VP (Vertebrate Paleontology) warehouse this afternoon to continue working through the rest of the bags of > 1/4" chunky matrix from the material collected from the Montbrook site in sandbags. Toward the end of the first of the bags I spotted something (increasingly) familiar in the picking box--yet another Notorynchus sp. Sevengill Shark tooth. This one a partial upper with some of the smaller cusps missing and part of the root gone. I'm starting to wonder if these are as rare as I've been lead to believe or if I'm becoming a Notorynchus whisperer.

 

  

 

      

 

In a different batch of matrix I spotted an interesting (but broken) Sand Tiger Shark, Carcharias taurus, tooth. Unlike "normal" teeth from this species (like the one pictured to the left which I also found today) this one had something funky going on with the side cusp. Never seen one with a multiple/serrated side cusp before. Likely, this is just some sort of growth anomaly and it would have been interesting to see if the cusp on the other side was likewise multi-tipped. Keep looking long enough and you'll see some interesting things.

 

Cheers.

 

-Ken

 

   

 

[Jackson g]

That is some impressive and commendable work you are doing there Ken! I couldn't imagine picking through bags like that for hours. I think my terrible vision would get worse trying discern the tiny fossils from the matrix, or maybe I would just drive myself nuts! It's a lot different to how I collect and sort out fossils in my area, that's forsure! Very cool

[digit]

I use a low power desk-mounted magnifier and some bright lights while picking through bags of the chunky matrix at the warehouse. For picking the very fine micro-matrix at home I have a camera-microscope that I can project a realtime HDMI image onto a large flatscreen monitor of what is on my picking plate. Makes them so large I could probably still spot the micro-fossils even without my contacts.

 

I enjoy the experience of spotting interesting specimens hidden within bags of matrix in the same way as I enjoy standing in the Peace River with a sifting screen looking for fossils. I don't get to keep any of the fossils I "find" but that's fine with me because I enjoy the finding much more than the owning. Most (but not all) volunteers would rather do other tasks than picking micro-matrix and so the museum and I have a synergistic relationship. There are racks and racks of boxes of sand-like matrix that could (and probably will) keep me going for years.

 

 

Cheers.

 

-Ken

 

 

[MarcoSr]

10 hours ago, digit said:

I use a low power desk-mounted magnifier and some bright lights while picking through bags of the chunky matrix at the warehouse. For picking the very fine micro-matrix at home I have a camera-microscope that I can project a realtime HDMI image onto a large flatscreen monitor of what is on my picking plate. Makes them so large I could probably still spot the micro-fossils even without my contacts.

 

I enjoy the experience of spotting interesting specimens hidden within bags of matrix in the same way as I enjoy standing in the Peace River with a sifting screen looking for fossils. I don't get to keep any of the fossils I "find" but that's fine with me because I enjoy the finding much more than the owning. Most (but not all) volunteers would rather do other tasks than picking micro-matrix and so the museum and I have a synergistic relationship. There are racks and racks of boxes of sand-like matrix that could (and probably will) keep me going for years.

 

 

Cheers.

 

-Ken

 

 

 

Ken

 

Wow, that is a lot of matrix, enough to keep volunteers busy for years.  Are you only picking Montbrook matrix or are you picking matrix from other sites?  Are researchers currently studying the specimens found with papers/publications in the works?  A comprehensive paper/publication on the shark and ray fauna would be of great interest to me.

 

Marco Sr.

 

[digit]

On shelves to the left of what can be seen in the photo are boxes of matrix from other localities. I had a quick look at what may be in my picking future once we get a bit more caught up on the Montbrook site. I didn't recognize many of the names but I do recall some matrix from a Panama site that I've already read papers about. I know of an unpublished PhD dissertation that may be of interest to you as well as two future papers on Florida fossil shark and ray fauna. One will be on the novel micro-chondrichthyans of Montbrook, Cookiecutter Creek and a few other localities in Florida.

 

 

Cheers.

 

-Ken