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  1. Here is a photo heavy and (for me) text light posting showing the sequence of Tammy and I finding a partial softshell turtle (Apalone sp.) carapace in the field at Montbrook (which was jacketed and removed on the last day of the spring digging season). I pulled the jacked and prepped the carapace over the course of a few months. The jacket was made in the field on 5-May-2021 and I retrieved the jacket (#573) from the storage area on 10-Jun-2021 and completed the prep today 23-Sep-2021. Lots of excavation into the jacket and cleaning and re-attaching parts. The pectoral girdle (scapula and corocoid bones) as well as the first cervical vertebra were left in the position where they were found to preserve the taphonomic information. A fun project that taught me a lot about fossil prep. Cheers. -Ken
  2. For the last several weeks Tammy and I have been volunteer digging every Wednesday and Saturday at the Montbrook site a little south of Gainesville (FL) with the Florida Museum of Natural History (FLMNH). The weather called for continuous light drizzle all day yesterday (Saturday) so we bumped the dig day to today (Sunday) instead. Normally, Sunday and Monday are the non-digging days at the site but the other days are occupied by small groups of volunteers and site managers. This morning was clear and cool with a steady breeze from the north. This meant several layers while packing up this morning and when we got to the site at 10am. The temps quickly rose throughout the morning and the layers of warm clothing were shed. Post-lunch it was quite warm with the sun beating down on your back and it was hard to fathom that it was actually chilly earlier in the day. We were digging in the same grid squares that we'd been focusing on for the last couple of weeks. Underneath several highly visibly banded layers of sterile sand we dropped into a layer that was rich with a tangle of fossils. The foundation for this cluster of fossil goodness was a large pelvis from a gomphothere (a 4-tusked elephant relative that is reasonably common at the site). Wedged in around this large flat pelvic bone were a couple of Trachemys (slider) turtle shells which were badly crushed and so did not merit being preserved in a plaster jacket and instead were "chunked out" into several small bags to attempt to be re-assembled later in the warehouse (possibly by me). We had started the morning by removing the plaster jacket that contained the majority of the gomph pelvis. There was more of this intermixed with other bones that will come out later as part of a jacket that might contain a pair of gator skulls--one in poor condition and one (underneath the pile-up) that might be in much nicer preservation that I discovered last week. I spent the day working around this mountain of bones. Tammy was working an adjacent grid square leveling it down and working on some clusters of bones that had cropped out in that square. Richard Hulbert (collections manager at the FLMNH and well-known identifier of Florida finds) was working on a section of articulated alligator vertebrae that was found a few weeks back several grid squares to the south. The only other participant today was Jonathan Bloch the department chair and curator for vertebrate paleontology at the FLMNH. He had found a large gomphothere leg bone and was clearing the area around it to make a pedestal so that it could be jacketed for removal. Most of the day was pretty run-of-the-mill for Montbrook. We pulled out lots of isolated Trachemys turtle shell pieces and random bits like gator vertebrae and teeth. These are the "background" fossils that are common at this site. Toward the end of the day Tammy pulled up an interesting bone that we had to pass around. From the size of it I guessed that it might be rhino and given the shape thought it might be something odd like a calcaneum or astragalus. When Richard had a look at it he confirmed that it was rhino but said it was one of the bones in the feet. I score that as correct with partial credit. Just half an hour before we were ready to leave at 4pm, I was working on digging down to complete the trench around the mountain of bones we would soon have to jacket. I completed the curved trench I was digging and was lowering it to the level of the adjacent grid square. After digging through some sterile layered sand I got down to a section that had some bone. We dig with flat-blade screwdrivers to loosen the sandy matrix and if we feel the resistance of a harder bone we switch to a dental pick for more careful exploration. I bagged up some broken-up bone fragments that looked like turtle shell pieces and, after running into more than simply an isolated bone in the sandy matrix, I moved to the side to attack the bony bit from another side--sneaking up on it to judge its extent. It was at this point when my dental pick uncovered a honeyed orange colored bone. This is the color we all secretly hope for while digging Montbrook. Most of the bones are either a well-preserved tan (like the rhino bit above), or a purplish color in a layer that preserves well but has lots of phosphatic matrix stuck to the bones making them difficult to clean-up or chalky white in a layer where the bones are not well mineralized. These bones (which we have named "pudding bones") are white and soft as a piece of wet drywall board. Orange, in contrast, is the color that many of the enameled mammal teeth preserve--it is the color we long to see emerge from the sand. Brushing away the sand from this speck of orange confirmed that what I was seeing was indeed a mammal tooth. Jonathan always jokes at the beginning of the day that he is here to find "something with teeth" as this indicates cranial material that is inherently more interesting than most post-cranial finds. Richard commented that it wasn't the curator that stumbled upon something with teeth but Jonathan was happy just to see a new find with teeth emerge from the sandy matrix. A bit more digging revealed three cusps of a proboscidean tooth but interestingly they were not from a gomphothere which are the most common hose-nose to be found at this site--it was instead mastodon! I believe only one other set of mastodon teeth have been found at the Montbrook site--also a smaller juvenile like this find. After a bit more uncovering we could see two complete 3-lophed teeth. The larger tooth was to the left indicating that this was toward the back of the maxilla (we could tell they were upper teeth not the lowers in the mandible based on the bone they were embedded in). This appeared to be a fragmented maxilla and no signs of tusks to the right have turned up (yet) but that could change with additional excavation. You have to put in a lot of time digging out fragments of turtle shell or other common finds before you make a notable discovery. Finding both rhino and mastodon make this a red letter day in our book. I won't be back to the site till next Wednesday but it will be interesting to see how much more has been revealed on Tuesday. Till then the grid squares with all those enviable finds will rest underneath a tarp awaiting our return. Cheers. -Ken
  3. Tammy and I have been volunteering at the Montbrook dig site in north-central Florida every Wednesday and Saturday for a while. We're part of a small group of local volunteer diggers who've been able to dig the site during the pandemic. We have a maximum of 6 people at the site with 4 volunteers (aka retired people who'd rather not golf or watch daytime TV) and 2 from the museum. Over the last couple of weeks we've worked to take out several gomphothere bones that have turned up in the grid squares that we've been working. Two Saturdays ago we started the jacket on the remaining part of a gomphothere pelvis (the flat ilium was jacketed and removed separately where there was a break in the bone during preservation). It was not dried enough by the end of the day to take that large and heavy jacket out by the end of the day. Some additional plastered burlap was added around the base to make sure the jacket would properly contain the contents when flipped. In addition to the residual gomph pelvis there was what looked to be a really nice alligator skull directly underneath the pelvis which made for a very tall jacket that was also very heavy. With limited crew we flipped that big jacket into the cargo net and (in stages, with rest between) lugged it up out of the pit and into the back of the museum van. While clearing the area around the gomph/gator cluster so we could encase it in plaster I came across the end (femoral head) of a gomphothere femur. It was toward the end of the day and there was much sand above the bone so it had to wait for another day. We had other obligations this last Saturday and so we could not volunteer that day. Someone in the group digging that day was working down the level of the grid square that the bone looked to be extending into. They didn't get too far as they were distracted by a rhino jaw that happened to be hiding in there. I had been sitting directly on top of it on my previous visit and had actually dropped the level of that 1m x 1m square by about 20 cm (~8"). Had I dug a bit more I would likely have hit the rhino material. This preparatory digging before an interesting find we've dubbed "pre-discovering" a fossil. With the rhino jaw jacketed and removed we were in position to continue to reduce the level of the sand/clay in the squares around the gomphothere femur. All that was showing when I first happened upon it was the rounded ball of the femoral head and the bulge of bone known as the greater trochanter which serves as an attachment for many leg muscles. We were wondering at which angle the rest of the bone (should it be present) would appear and at what level--the laminated layers of sand and clay dip at a pretty steep slope and bones usually follow the layers. Tammy spent the early part of the morning digging down from the opposite (distal) end of where the femur should end trying to gauge its length and orientation. When she was coming up with mostly sand she switched tactics to following the bone shaft down from the hip to see where it was leading. I spent the morning taking an adjacent square down about 30 cm (~1') to level out the area in which we were working. Because the layers dip down in this direction (to the east) the sand I was digging in was above the area in which all the interesting fossils started to appear. Occasionally, while digging in sterile sand an odd isolated fossil will turn up. Absolutely none did in this grid square. I was able to remove about 30 of the large plastic kitty litter pails of sand without being bothered with any pesky fossils getting in my way. Once I had my corner square dropped to an appropriate level I started lowering the level of the adjacent square. By this time Tammy had followed the femur to the opposite end. Unfortunately, the preservation on the distal end was not nearly as solid and was instead rather punky--a preservation we've dubbed "pudding bone" which is as problematic as it sounds. This end will require quite a bit of consolidation with the plastic B72 dissolved in acetone to make a stabilizing glue. In the left image above, you can see the rounded ball of the femoral head peeking out between Tammy's right hand (with stylish orange glove) and the bright yellow cat litter pail. You can get a better view of the femoral head and the greater trochanter below it on the left edge of the bone as well as the extent to the more crumbly distal end in the right image above. At this point we knew the size and orientation of this bone and had started to remove higher material around the vicinity so we'd have room to jacket it and flip it over when removing. I started working down the higher corner visible in front of Tammy to the left edge of the left image above. This was still mostly soft (and very easy to dig) sugar sand with some thinner clay layers and chunks of orangish clay nodules. While lowering this area and making room so we could start trenching around the bone to make a nice pedestal for the jacket I found my first fossil of the day. Digging most of the day in sterile layers is necessary work but often does not result in a full bone bag at the end of the day. I've dug many days when no label for my disused bone bag had to be written up. I'd been digging since 10:00am and it was now around 3:45pm (we clean-up and leave at 4:00pm) so it was a little late in the day to be uncovering my first find of the day. This one was worth the wait though as I spotted the gleam of orange that can sometimes herald good news. Of course, 99 times out of 100 the orange is just one of those sticky clay nodules that get dug out and tossed on the spoil pile with the rest of the sand. This one was a faintly different shade of orange and indicates mammal tooth (for some reason mammalian tooth enamel often preserves as a dull orange at this site). The orange was on a small clump that freed itself while I was digging through the loose sugar sand. Closer inspection with a dental pick revealed the gleam of enamel and not sticky iron rich clay! A little water from the hose was able to soften the sandy clay around it and my first (and only) find of the day turned out to be a really sweet and absolutely tiny baby gomphothere molar. This one got slipped into a protective vial that we use for more delicate specimens and was padded with bit of tissue. While trying to finish up a bit more of the trench I was digging around the femur I hit some more bone right at the corner of the 4 grid squares which we mark with little orange wire flags. At this point it was really too late to do more work on prepping this for jacketing and that task would fall on anyone working the area Thursday or Friday. If nobody ends up working that square before Saturday then Tammy and I will be back to complete trenching so we have a pedestal that we can jacket. With the end of the day's digging rapidly approaching we protected the exposed bone with some empty sandbags till the next time it receives some attention. You can see below the squares I was working as my mild OCD drives me to leave my work area with sharp crisp walls and corners and flattened bases. Only 1 bone in my bone bag--but I'm quite happy with that. Cheers. -Ken
  4. The spring 2021 digging session opened last week at the Montbrook site in north central Florida. It is a short drive from Gainesville where Tammy and I relocated last summer. One of the reasons for choosing Gainesville as our new home is so that we can volunteer more with the Florida Museum of Natural History (FLMNH). It is really great to be able to do a day of volunteer digging at the Miocene Montbrook site without a 5 hour trip up from South Florida and hotel reservations. Previously, we'd book a 3-4 day span of volunteer digging to make the trip worth the effort. Being able to dig for a single day and then rest up after (consuming fistfuls of ibuprofen) has its advantages. Usually, the museum would open this dig to a group of nearly 500 volunteers (students, retirees, and even out-of-state visitors) who have all put in countless hours of digging this site since 2016. Safety concerns due to the pandemic have forced the museum to limit the attendance at the digs to a smaller number of individuals and only locals with years of experience at the site. Luckily, we fit that category. We wear masks at the site and though we are not in one of the higher priority groups for the COVID vaccine many of the other retirees have had at least their first shot. While we are fortunate to be able to dig as part of the skeleton crew (pun certainly intended) we look longingly forward to being past the pandemic and seeing many old friends at the dig site. We were out for the season opener last Wednesday and Richard Hulbert assigned Tammy and me to a pair of adjoining (1m x 1m) grid squares. At this section of the dig site the underlying layers of the formation slant down steeply from west to east--possibly the sloping bank of the river which is what we intuit this site to represent. I spent the morning removing the soft "sugar" sand on the top layer of my grid square. We know from other adjacent grid squares (several of which I've excavated) that this layer seems to be above the good fossiliferous layers and only rarely has isolated fossils (usually only small bits of Trachemys slider turtle shell). Being soft like beach sand, this layer can be dug out quickly and efficiently with our usually excavation tool--a standard blade screwdriver. I filled and hauled out dozens of plastic cat litter containers of this sand, dumping them on the spoil pile out of the pit in which we were digging. Good exercise and useful excavation but did not add many fossils to my "bone bag" for that day. Tammy worked the adjacent square "up-slope" of my square. She was already at the level of the gritty layer below the sugar sand. This gritty layer contains larger rocks and has a more grainy appearance. It also seems to have a lot of clay particles mixed in which makes it concrete hard when dried out. We infer that these layers may represent major storms that raised the river level and increased its flow rate. As the storm subsided the more coarse material in suspension with the faster flow started to drop out and form this layer. Often, it contains interesting micro-fossils (and occasionally larger fossils as well). Tammy was digging out this layer and putting it into sandbags so it could be processed later washing it through screens to separate the micro-matrix from the silty fine sand. This was to be reserve material for an outreach project for science teachers in Florida who will be receiving matrix to pick through with their classes. Tammy needed the hose to soften the matrix--we have a gravity-fed water supply with a large tank and a jumble of hoses. She worked down her corner of the square and bagged it but it was like melting concrete with a hose and scraping it with a screwdriver. My gritty layer was under the layer of sugar sand and so was already somewhat damp and not nearly so hardened. By the end of the day I had taken down the top part of what I had been calling the "ski slope". The second photo is how we left the site at the end of the day. We were busy last Saturday (we now dig every Wednesday and Saturday) and didn't make it out. Some of the other long-term volunteers worked our squares that day removing more material and exposing a partially articulated Macrochelys snapping turtle carapace. At the end of the day they had also uncovered a small section of bone that looked like it might be part of a skull. Alligator was a good candidate and that's what we were told when we picked up work on this square yesterday (Wednesday). It was a chilly morning (starting out below freezing) and this is why they have delayed the starting time to 10am. Because it was a sunny day, before long we were able to ditch many of the multiple layers we had started out with. Richard reassigned us to this pair of squares and Tammy worked the square with the snapping turtle carapace starting by uncovering more of the suspected alligator skull. I worked my adjacent square again. It had some of the gritty layer removed but sitting out in the sun for several days meant that it had hardened and I ended up making copious use of the hose this time trying to soften this "concrete" and get through to a hopefully fossiliferous layer below--the same layer that held Tammy's snapping turtle and mystery bones. Once I got down to the bottom edge of my hard gritty layer I uncovered the layer of softer sand below it. At the interface of these two distinct layers I started finding some fossils. If this gritty layer represents material laid down during a flood event then it makes sense that some of the larger objects would have dropped out of the flow first followed by the gritty material. The finer clay particles would have settled last and then probably percolated between the grains of the grit and completed the "paving" for this weather event recorded in the layers at this site. I started to find a few bits like a pieces of a Trachemys plastron (2 left xiphiplastron elements--so not an associated set) and some gator osteoderms (which we call "cookies") and a really sweet large shark vert. They were all at the bottom of a chunk of the gritty material where it separated from the softer sand layer below. While I was busy "unpaving" the "ski slope" in my grid square Tammy was uncovering more around the suspected alligator skull. She had switched from the screwdriver to a dental pick as she worked closer towards the area with the uncovered bone. When she came upon a tooth and started uncovering it she was surprised that it did not look like a gator tooth. A little more excavation revealed a row of teeth. It was quite obvious they were mammal teeth and not gator and so we called over Richard who used a hose set to a fine mist to help gently wash away the matrix to reveal more. It turned out to be a lower jaw from a peccary (Protherohyus brachydontus)! They have a few other pieces of peccary skull but this is the first lower jaw complete with teeth. An excellent find that would be plaster jacketed and removed for preparation in the lab. I switched over to Tammy's square for a bit and we worked together to dig a trench around the jaw so that it would be raised on a pedestal for jacketing. There were a few Trachemys turtle bones discovered while trenching but luckily the were isolated finds. Occasionally, an interesting find (like the jaw) ends up in a cluster of different sets of bones and it gets complicated to figure out how to decide what gets included in the jacket. Smaller jackets are, of course, easier to remove, transport and prepare so it is always good to be able to isolate a particular specimen. We were able to create a roomy trench around most of the jaw but could only make a more narrow slot between the pedestal we were forming and the snapping turtle carapace adjacent to it. Thankfully, it was just enough to be able to jacket the specimen and remove it safely. We covered the articulated snapping turtle carapace bones with a sandbag so we would not get plaster slopped onto the specimens. Now that the peccary jaw is out it will be easier to excavate the snapping turtle to see how much is there. We protected the jaw by packing on some clean damp sand and made a more level base so this jacket would rest properly when it is flipped and worked in the lab from the underside. Tammy gets recorded as the co-collector along with the volunteer that first spotted it. I could have easily titled this post "The Day of the Peccary" or "Peccary Appreciation Day" but that would have spoiled the surprise. We had an additional surprise to this peccary-themed day. Sue, another long-time volunteer (pictured in a blue sweatshirt in a photo above and a gray jacket the week before in the very first photo) was working a few squares over and mostly finding turtle bones and a fish vertebrae came across something interesting. When she showed it to Richard he was amazed to see it was half a broken peccary tusk. A good portion of the tip was missing and though it looked to be an old (not fresh) break at the end he asked Sue if she had the other part. She didn't but she said she'd go through her bucket of matrix again before dumping it to make sure it wasn't hiding in some clump. She went through her bucket twice and set aside any of the bits she found. Amazingly, the missing piece turned up. She had not recognized it and though it had turned up earlier she methodically searched through her bucket of matrix with a fine-tooth comb (twice). The effort was well rewarded with a fine looking tusk that may very well be associated with the nearby jaw in Tammy's square. By the time we left at the end of the day I had leveled and cleared about half of my square down below the hardened gritty layer to the softer sandy layer below. You can see the neat smooth layer that I'm known for while digging at this site in the left in photo below. In Tammy's square to the right you can see the deeper pit in the upper right corner where the jacket containing the peccary jaw was removed. The sandbag with sand holding it down next to that is where the snapping turtle carapace is being protected. While Tammy was finishing off the day removing the higher level material shown at the middle of the right edge in the photo she came across a bit of bone. It was getting late and we were starting to clean up and get ready to leave. She showed Richard the bone that she had exposed and asked him if she should continue exposing it or leave it for later. We were wondering if it might be associated with a gomphothere scapula that is in the adjacent square. You can see a sandbag along the lower right edge in the image that is protecting and indicating where this fossil is positioned. It can't be removed till the adjacent material is dropped sufficiently to allow the extent of this scapula to be determined and allow for proper trenching and jacketing. The more that Tammy uncovered this bone the more it didn't seem to be related to the scapula. In the end she marked it with an empty plastic bone bag we had handy and weighted it down with a handful of sand so it would not blow away. We'll likely get back to these squares this Saturday and Tammy can investigate this bone more fully and work to get the snapping turtle carapace pedestalled and jacketed. I'll probably continue removing material from the square I've been working on and hope to get to some nicely fossiliferous material that was hiding below the gritty pavement. Who knows what will turn up next? And that's precisely why we keep coming back--even on chilly mornings. Cheers. -Ken
  5. digit

    Gopher? Go figure!

    Since moving from South Florida up to Gainesville I've finally been about to help the Florida Museum of Natural History (FLMNH) with some volunteer effort by picking through washed and dried matrix that was collected back in 2018 from the Montbrook site just a little way south of Gainesville. Tammy and I have spent several days over the last couple of years volunteering to dig our assigned 1 m x 1 m squares at the site bagging up the smaller fossils and excavating pedestals for larger specimens to be jacketed. Most of the sandy/silty matrix does not have very interesting micro-fossils but there are a couple of distinctive layers where the matrix is a more coarse fine gravel instead of sand. The understanding is that this probably represents a horizon where there was a faster water flow due to something like a tropical storm (similar to what Florida is experiencing at the moment). The Montbrook site is assumed to represent a river environment and the faster current during a flooding situation would transport and then deposit this more coarse material (possibly along with a more interesting and denser bunch of fossils). Richard Hulbert has me on the lookout for specimens from several taxa that are known from the Montbrook site only by a few micro-fossils. The most interesting micros are the rarer types of animals. There are lots of shark (and ray) teeth and plenty of tiny fish teeth to keep things interesting while picking but the real prizes are things like mammal fossils or the even rarer bird bones. There are several rodent taxa that are represented in the Montbrook faunal list by a just a few teeth and bones so Richard has me keeping an eye out for any rodent material. I spotted something interesting yesterday that had that rodent look and feel but was unlike anything I'd encountered before while picking Florida micro-matrix. I've seen plenty of very distinctive Cotton Rat (Sigmodon sp.) as well as vole teeth and even a single mole tooth but I was uncertain what had just turned up so I took some photos--composited together with my photo-stacking software to allow for a decent depth of field beyond what is available from any one single image. I sent these photos to Richard and received the reply today that this specimen is tooth from a gopher (family Geomyidae) and while this taxon is already known from Montbrook it was previously only represented by 2 teeth and this new third tooth is much more complete than the previous ones and so it a scientifically important specimen for this site. The volunteer that bagged the matrix from the Montbrook site back in 2018 goes in the database as the collector of record and gets credit for this really nice find (though they had no idea of what might or might not be in the matrix material while filling the sandbag with the material nearly 2 years ago). While my name won't be associated with this specimen, I did have the thrill of seeing it appear on my picking plate yesterday afternoon and the added rush of learning what it was today (and that it is something special). That's the true reward. Cheers. -Ken
  6. Just came back from an afternoon at the FLMNH vertebrate paleontology warehouse sorting through bone bags from the Montbrook site. Richard Hulbert, Collection Manager, was there as well working on cataloging specimens from the trays of catalogable specimens that I'd separated from the scrappy bones last month. He came over to show me a set of 3 neural bones from the carapace of the Trachemys slider turtle that is ubiquitous at the site. I remember seeing these 3 bones (neurals 3 through 5) that run along the midline of the turtle's upper shell (carapace) when I determined they were associated and fit together. Associated bones are cataloged as a set rather than as individual bones. I recall these bones having rounded markings on them but likely was distracted with something else and didn't take the time to dig out the pits of lithified sand that filled these cavities. Richard took the time to clean out the matrix and it was quite apparent that this was one lucky turtle (depending on your point of view). You can clearly see that an alligator had managed to get this turtle into its mouth and had bit down at least twice leaving two distinct rows of tooth marks along the midline of this turtle's shell. The wounds are slightly healed and the fact that the neurals were found in close proximity within one of the grid squares and were not found digested and part of a gator coprolite means that this lucky turtle survived the attack and continued to live for some time after. Always fun when these little taphonomic clues can be interpreted to tell something of the life story of the individual. Cheers. -Ken
  7. 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
  8. Still fossil hunting indoors during the summer (and the pandemic) amusing myself (and helping the FLMNH) by picking through micro-matrix from the Montbrook dig site in Florida. I've made some other posts featuring the interesting micros I've been finding to try to share a bit of the world of micro-fossils with a wider audience (Florida has more than megalodon teeth). I was picking through a sample of Montbrook micro-matrix. It was collected back in 2018 and was subsequently washed, dried, and sat in a zip-top bag for years awaiting someone to spend about a dozen hours picking through it for interesting specimens. In addition to the monotony of the very abundant common fossil types (fish verts, fish teeth, gar scales, Rhizoprionodon and Dasyatis teeth) my efforts are occasionally rewarded by spotting something out of the ordinary. Sometimes the novelties are just a rarer type of previously seen fossil--a tiny ray dermal denticle the size and shape of an asterisk * or a pretty little serrated Galeorhinus (Tope Shark/Houndshark) tooth. What really makes the long hours pay off is when I encounter a good mystery. Some of the mystery finds are only mysterious to me as they are answered promptly by Richard Hulbert when I send him micro-photographs of some "unknown". I am slowly crawling up the learning curve and broadening my knowledge of the micro-fossil types being found at the Montbrook site. The real fun happens when I get something that's a stumper--a real novelty for the locality. The Montbrook micro-matrix material has a large amount of marine (and freshwater) fish material hiding in it. There are teeth from drum, barracuda, porgy, pinfish and several other marine fish families found floating loosely in the matrix. Tiny button-shaped teeth that resemble those from drums are likely the pharyngeal teeth from wrasses. One of the former mysteries that I now have locked into my set of search images is the tiny (only a few millimeters across) pharyngeal tooth plates for a small species of wrasse. Here's one I found which was full of these little button teeth. About two weeks ago I spotted an unusual little specimen in my picking plate. I could tell from the bone structure that it was "fishy" (in a good way ) but the attached tooth type was something new that I had not encountered before. I could see that this piece was a (mostly) complete lower left quarter jaw--you can see the zipper-like symphyseal suture at the midline of the lower jaw indicating that it was not fragmented and there would be no additional teeth expected in this portion of the jaw. My first thoughts about fishes I knew that had a single tooth in each quarter jaw led me to think about parrotfishes but this was quickly dismissed because I knew that parrotfish "beaks" were composed of tiny tooth plates which are continuously added from the base as the plates wear and break-off on the occlusal surface while the fish feeds by scraping algae from the surface of the substrate. BONUS FACT: Parrotfishes ingest a large amount of calcium carbonate (old coral skeleton) while feeding and the majority of tropical white sand beaches are in fact composed primarily of parrotfish poop. Richard forwarded my photographs to a student who specializes in osteichthyan (bony) fishes and I went back to picking more micro-matrix. I had a feeling that the answer would be blindingly obvious in hindsight. Had I thought about it for a moment or two more I probably could have arrived at the answer myself but so many of these mystery finds turn out to be something unexpected that I just trusted that an expert would soon solve the mystery for us. Our fishy expert was in the process of a long cross country move to continue her education at UC Berkeley but before long we got our answer--as obvious as I'd predicted. In her opinion the jaw piece belonged to a member of the order Tetraodontiformes and likely in the family Tetraodontidae (pufferfishes). The answer is right there in the scientific name (Greek, tetra = four + Greek, odous = tooth, teeth) referring to the 4 large teeth fused into a beak-like structure for feeding on hard shells of crustaceans and mollusks. A little bit of searching online quickly turned up images that closely matched my find confirming this diagnosis. A related family in the Tetraodontiformes is the Diodontidae (known as porcupinefishes, balloonfishes, blowfishes but also confusingly as pufferfishes). The mouth plates for this family are fused into two plates, upper and lower (Greek, di = two + Greek, odous = tooth, teeth) and are relatively common finds in the Florida fossil record. Anybody who has hunted the Peace River long enough has encountered at least one of these solidly constructed mouth parts with stacks of tooth plates edged in fine maxillary teeth. @Harry Pristis has a fine example of Florida finds in his library of images. There are copious additional images available online with a simple search. These diodontid tooth plates also occur occasionally in the Montbrook micro-matrix but it appears that the tetraodontid jaw specimen likely represents a new family group for the Montbrook faunal list. It is great fun when a tiny find starts as a micro-mystery, serves as a learning example to expand my knowledge base, and finishes by expanding the envelope about what is known of the taxonomic diversity of the site. Cheers. -Ken
  9. digit

    Stingray City

    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
  10. For several years now we've been fortunate enough to be able to take part in volunteer digs with the Florida Museum of Natural History (FLMNH), University of Florida (Gainesville). The site was discovered at the end of 2015 and we've been participating during the dig seasons (the drier cooler part of the year) since 2016. The site is on private property but the landowner is very enlightened and understands the importance of this site which gives a rare glimpse into the Hemphillian North American Land Mammal Age (NALMA) period dating around 5.0-5.5 mya. The owner has been very supportive of letting the museum (and its staff, students, and volunteers) onto his property and even helps quite frequently using his excavators to clear the overburden and manage the site for drainage. You can learn more about the site and the finds here: https://www.floridamuseum.ufl.edu/montbrook/ We were previously out to the site last November digging in the main pit. Tammy found some nice gomphothere bones and I dug a rather sterile sandy grid square but happened upon a cache of over a dozen associated gator osteoderms--both the larger circular ones from the back and the elongated ones from the border of the tail. The site is closing for the season at the end of March so we found some time in our schedule to make the trip north for a final dig before the site gets tarped for the summer. We had planned on heading up on Sunday evening for the dig on Monday through Wednesday but it is nice to have flexibility in our schedule. Tammy and I are looking to relocate to the Gainesville area so that I can volunteer more with the FLMNH (and attend these digs more often). We've been looking at houses in the Gainesville area for several months now and periodically make the 5 hour drive from South Florida to see properties of interest. Late Thursday a property that looked interesting popped-up. We decided to modify our schedule to drive up early Friday morning instead. Unfortunately, (as is often the case) the house and property looked better online than in person. We visited a few other newer properties in the area and then decided to head up to Jacksonville (about a 1.5 hour drive) to stay with friends over the weekend. Hotels tend to bump up their rates over the weekends--We've seen hotel rates triple in Gainesville when the alumni return for Florida Gators home football games. We spent an enjoyable weekend with our friends up in JAX and headed back down on Sunday (getting in an open house viewing before checking into our hotel in Gainesville). We were ready for our 3-day dig at Montbrook starting the next morning.
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